diff --git a/.babelrc b/.babelrc
index 453c2e5d9..2253b6c75 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,9 +1,10 @@
 {
   "presets": [
     "@babel/preset-env",
-    "@babel/preset-typescript",
+    "@babel/preset-typescript"
   ],
   "plugins": [
-    "@babel/plugin-transform-runtime"
-  ],
+    "@babel/plugin-transform-runtime",
+    "@babel/plugin-proposal-class-properties"
+  ]
 }
diff --git a/.npmignore b/.npmignore
deleted file mode 100644
index 98d40b1c3..000000000
--- a/.npmignore
+++ /dev/null
@@ -1,6 +0,0 @@
-doc
-.vscode/
-npm-debug.log
-# The following (and `.npmignore` in general) can be removed again once this bug is fixed:
-# https://github.com/linkeddata/rdflib.js/issues/369
-lib/index.d.ts
diff --git a/package-lock.json b/package-lock.json
index bb27e00c3..7cf2e03dd 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -339,6 +339,163 @@
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+            "@babel/code-frame": "^7.0.0",
+            "@babel/parser": "^7.7.4",
+            "@babel/types": "^7.7.4"
+          }
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+        "@babel/traverse": {
+          "version": "7.7.4",
+          "resolved": "https://registry.npmjs.org/@babel/traverse/-/traverse-7.7.4.tgz",
+          "integrity": "sha512-P1L58hQyupn8+ezVA2z5KBm4/Zr4lCC8dwKCMYzsa5jFMDMQAzaBNy9W5VjB+KAmBjb40U7a/H6ao+Xo+9saIw==",
+          "dev": true,
+          "requires": {
+            "@babel/code-frame": "^7.5.5",
+            "@babel/generator": "^7.7.4",
+            "@babel/helper-function-name": "^7.7.4",
+            "@babel/helper-split-export-declaration": "^7.7.4",
+            "@babel/parser": "^7.7.4",
+            "@babel/types": "^7.7.4",
+            "debug": "^4.1.0",
+            "globals": "^11.1.0",
+            "lodash": "^4.17.13"
+          }
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+        "@babel/types": {
+          "version": "7.7.4",
+          "resolved": "https://registry.npmjs.org/@babel/types/-/types-7.7.4.tgz",
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+          "dev": true,
+          "requires": {
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+            "lodash": "^4.17.13",
+            "to-fast-properties": "^2.0.0"
+          }
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+          "resolved": "https://registry.npmjs.org/debug/-/debug-4.1.1.tgz",
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+          "dev": true,
+          "requires": {
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+          "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
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+          "dev": true
+        }
+      }
+    },
     "@babel/plugin-proposal-dynamic-import": {
       "version": "7.5.0",
       "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-dynamic-import/-/plugin-proposal-dynamic-import-7.5.0.tgz",
@@ -1040,11 +1197,20 @@
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+      "version": "4.2.6",
+      "resolved": "https://registry.npmjs.org/@types/chai/-/chai-4.2.6.tgz",
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       "dev": true
     },
+    "@types/chai-as-promised": {
+      "version": "7.1.2",
+      "resolved": "https://registry.npmjs.org/@types/chai-as-promised/-/chai-as-promised-7.1.2.tgz",
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+      "dev": true,
+      "requires": {
+        "@types/chai": "*"
+      }
+    },
     "@types/connect": {
       "version": "3.4.32",
       "resolved": "https://registry.npmjs.org/@types/connect/-/connect-3.4.32.tgz",
@@ -1054,6 +1220,16 @@
         "@types/node": "*"
       }
     },
+    "@types/dirty-chai": {
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/@types/dirty-chai/-/dirty-chai-2.0.2.tgz",
+      "integrity": "sha512-BruwIN/UQEU0ePghxEX+OyjngpOfOUKJQh3cmfeq2h2Su/g001iljVi3+Y2y2EFp3IPgjf4sMrRU33Hxv1FUqw==",
+      "dev": true,
+      "requires": {
+        "@types/chai": "*",
+        "@types/chai-as-promised": "*"
+      }
+    },
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       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/@types/events/-/events-3.0.0.tgz",
@@ -1092,6 +1268,12 @@
         "@types/node": "*"
       }
     },
+    "@types/jsonld": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/@types/jsonld/-/jsonld-1.5.0.tgz",
+      "integrity": "sha512-EG2N8JLQ1xDfO6Z/1QRdiUcYX3428CqVRqmY7LyK5or5J1RQ16dpKH6qQ4umVD0vBHU47xHlMeyMbQ6o+6tiYg==",
+      "dev": true
+    },
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       "resolved": "https://registry.npmjs.org/@types/mime/-/mime-2.0.1.tgz",
@@ -1634,6 +1816,15 @@
         }
       }
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+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/backbone/-/backbone-1.4.0.tgz",
+      "integrity": "sha512-RLmDrRXkVdouTg38jcgHhyQ/2zjg7a8E6sz2zxfz21Hh17xDJYUHBZimVIt5fUyS8vbfpeSmTL3gUjTEvUV3qQ==",
+      "dev": true,
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@@ -1841,7 +2032,7 @@
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-      "resolved": "https://registry.npmjs.org/browserify-aes/-/browserify-aes-1.2.0.tgz",
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@@ -1878,7 +2069,7 @@
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-      "resolved": "https://registry.npmjs.org/browserify-rsa/-/browserify-rsa-4.0.1.tgz",
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@@ -1923,7 +2114,7 @@
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@@ -2440,7 +2622,7 @@
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@@ -2673,7 +2855,7 @@
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+    "handlebars": {
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+      "resolved": "https://registry.npmjs.org/typedoc-default-themes/-/typedoc-default-themes-0.6.1.tgz",
+      "integrity": "sha512-z5AWKqQDz7igl9WkUuafx8cEm4MPVQGMpbWE+3lwVOaq+U4UoLKBMnpFQWh/4fqQ3bGysXpOstMxy2OOzHezyw==",
+      "dev": true,
+      "requires": {
+        "backbone": "^1.4.0",
+        "jquery": "^3.4.1",
+        "lunr": "^2.3.8",
+        "underscore": "^1.9.1"
+      }
+    },
     "typescript": {
-      "version": "3.6.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.6.3.tgz",
-      "integrity": "sha512-N7bceJL1CtRQ2RiG0AQME13ksR7DiuQh/QehubYcghzv20tnh+MQnQIuJddTmsbqYj+dztchykemz0zFzlvdQw==",
+      "version": "3.7.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.7.2.tgz",
+      "integrity": "sha512-ml7V7JfiN2Xwvcer+XAf2csGO1bPBdRbFCkYBczNZggrBZ9c7G3riSUeJmqEU5uOtXNPMhE3n+R4FA/3YOAWOQ==",
       "dev": true
     },
-    "uc.micro": {
-      "version": "1.0.6",
-      "resolved": "https://registry.npmjs.org/uc.micro/-/uc.micro-1.0.6.tgz",
-      "integrity": "sha512-8Y75pvTYkLJW2hWQHXxoqRgV7qb9B+9vFEtidML+7koHUFapnVJAZ6cKs+Qjz5Aw3aZWHMC6u0wJE3At+nSGwA==",
-      "dev": true
+    "uglify-js": {
+      "version": "3.7.1",
+      "resolved": "https://registry.npmjs.org/uglify-js/-/uglify-js-3.7.1.tgz",
+      "integrity": "sha512-pnOF7jY82wdIhATVn87uUY/FHU+MDUdPLkmGFvGoclQmeu229eTkbG5gjGGBi3R7UuYYSEeYXY/TTY5j2aym2g==",
+      "dev": true,
+      "optional": true,
+      "requires": {
+        "commander": "~2.20.3",
+        "source-map": "~0.6.1"
+      },
+      "dependencies": {
+        "commander": {
+          "version": "2.20.3",
+          "resolved": "https://registry.npmjs.org/commander/-/commander-2.20.3.tgz",
+          "integrity": "sha512-GpVkmM8vF2vQUkj2LvZmD35JxeJOLCwJ9cUkugyk2nuhbv3+mJvpLYYt+0+USMxE+oj+ey/lJEnhZw75x/OMcQ==",
+          "dev": true,
+          "optional": true
+        },
+        "source-map": {
+          "version": "0.6.1",
+          "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
+          "integrity": "sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==",
+          "dev": true,
+          "optional": true
+        }
+      }
     },
     "underscore": {
       "version": "1.9.1",
@@ -8680,6 +8916,12 @@
       "integrity": "sha1-+OGqHuWlPsW/FR/6CXQqatdpeHY=",
       "dev": true
     },
+    "wordwrap": {
+      "version": "0.0.3",
+      "resolved": "https://registry.npmjs.org/wordwrap/-/wordwrap-0.0.3.tgz",
+      "integrity": "sha1-o9XabNXAvAAI03I0u68b7WMFkQc=",
+      "dev": true
+    },
     "worker-farm": {
       "version": "1.7.0",
       "resolved": "https://registry.npmjs.org/worker-farm/-/worker-farm-1.7.0.tgz",
@@ -8691,7 +8933,7 @@
     },
     "wrap-ansi": {
       "version": "2.1.0",
-      "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-2.1.0.tgz",
+      "resolved": "http://registry.npmjs.org/wrap-ansi/-/wrap-ansi-2.1.0.tgz",
       "integrity": "sha1-2Pw9KE3QV5T+hJc8rs3Rz4JP3YU=",
       "dev": true,
       "requires": {
@@ -8760,12 +9002,6 @@
         "async-limiter": "~1.0.0"
       }
     },
-    "xmlcreate": {
-      "version": "2.0.1",
-      "resolved": "https://registry.npmjs.org/xmlcreate/-/xmlcreate-2.0.1.tgz",
-      "integrity": "sha512-MjGsXhKG8YjTKrDCXseFo3ClbMGvUD4en29H2Cev1dv4P/chlpw6KdYmlCWDkhosBVKRDjM836+3e3pm1cBNJA==",
-      "dev": true
-    },
     "xmldom": {
       "version": "0.1.27",
       "resolved": "https://registry.npmjs.org/xmldom/-/xmldom-0.1.27.tgz",
@@ -8790,22 +9026,21 @@
       "dev": true
     },
     "yargs": {
-      "version": "13.2.2",
-      "resolved": "https://registry.npmjs.org/yargs/-/yargs-13.2.2.tgz",
-      "integrity": "sha512-WyEoxgyTD3w5XRpAQNYUB9ycVH/PQrToaTXdYXRdOXvEy1l19br+VJsc0vcO8PTGg5ro/l/GY7F/JMEBmI0BxA==",
+      "version": "13.3.0",
+      "resolved": "https://registry.npmjs.org/yargs/-/yargs-13.3.0.tgz",
+      "integrity": "sha512-2eehun/8ALW8TLoIl7MVaRUrg+yCnenu8B4kBlRxj3GJGDKU1Og7sMXPNm1BYyM1DOJmTZ4YeN/Nwxv+8XJsUA==",
       "dev": true,
       "requires": {
-        "cliui": "^4.0.0",
+        "cliui": "^5.0.0",
         "find-up": "^3.0.0",
         "get-caller-file": "^2.0.1",
-        "os-locale": "^3.1.0",
         "require-directory": "^2.1.1",
         "require-main-filename": "^2.0.0",
         "set-blocking": "^2.0.0",
         "string-width": "^3.0.0",
         "which-module": "^2.0.0",
         "y18n": "^4.0.0",
-        "yargs-parser": "^13.0.0"
+        "yargs-parser": "^13.1.1"
       },
       "dependencies": {
         "ansi-regex": {
@@ -8814,6 +9049,17 @@
           "integrity": "sha512-1apePfXM1UOSqw0o9IiFAovVz9M5S1Dg+4TrDwfMewQ6p/rmMueb7tWZjQ1rx4Loy1ArBggoqGpfqqdI4rondg==",
           "dev": true
         },
+        "cliui": {
+          "version": "5.0.0",
+          "resolved": "https://registry.npmjs.org/cliui/-/cliui-5.0.0.tgz",
+          "integrity": "sha512-PYeGSEmmHM6zvoef2w8TPzlrnNpXIjTipYK780YswmIP9vjxmd6Y2a3CB2Ks6/AU8NHjZugXvo8w3oWM2qnwXA==",
+          "dev": true,
+          "requires": {
+            "string-width": "^3.1.0",
+            "strip-ansi": "^5.2.0",
+            "wrap-ansi": "^5.1.0"
+          }
+        },
         "string-width": {
           "version": "3.1.0",
           "resolved": "https://registry.npmjs.org/string-width/-/string-width-3.1.0.tgz",
@@ -8833,13 +9079,24 @@
           "requires": {
             "ansi-regex": "^4.1.0"
           }
+        },
+        "wrap-ansi": {
+          "version": "5.1.0",
+          "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-5.1.0.tgz",
+          "integrity": "sha512-QC1/iN/2/RPVJ5jYK8BGttj5z83LmSKmvbvrXPNCLZSEb32KKVDJDl/MOt2N01qU2H/FkzEa9PKto1BqDjtd7Q==",
+          "dev": true,
+          "requires": {
+            "ansi-styles": "^3.2.0",
+            "string-width": "^3.0.0",
+            "strip-ansi": "^5.0.0"
+          }
         }
       }
     },
     "yargs-parser": {
-      "version": "13.0.0",
-      "resolved": "https://registry.npmjs.org/yargs-parser/-/yargs-parser-13.0.0.tgz",
-      "integrity": "sha512-w2LXjoL8oRdRQN+hOyppuXs+V/fVAYtpcrRxZuF7Kt/Oc+Jr2uAcVntaUTNT6w5ihoWfFDpNY8CPx1QskxZ/pw==",
+      "version": "13.1.1",
+      "resolved": "https://registry.npmjs.org/yargs-parser/-/yargs-parser-13.1.1.tgz",
+      "integrity": "sha512-oVAVsHz6uFrg3XQheFII8ESO2ssAf9luWuAd6Wexsu4F3OtIW0o8IribPXYrD4WC24LWtPrJlGy87y5udK+dxQ==",
       "dev": true,
       "requires": {
         "camelcase": "^5.0.0",
@@ -8847,58 +9104,14 @@
       }
     },
     "yargs-unparser": {
-      "version": "1.5.0",
-      "resolved": "https://registry.npmjs.org/yargs-unparser/-/yargs-unparser-1.5.0.tgz",
-      "integrity": "sha512-HK25qidFTCVuj/D1VfNiEndpLIeJN78aqgR23nL3y4N0U/91cOAzqfHlF8n2BvoNDcZmJKin3ddNSvOxSr8flw==",
+      "version": "1.6.0",
+      "resolved": "https://registry.npmjs.org/yargs-unparser/-/yargs-unparser-1.6.0.tgz",
+      "integrity": "sha512-W9tKgmSn0DpSatfri0nx52Joq5hVXgeLiqR/5G0sZNDoLZFOr/xjBUDcShCOGNsBnEMNo1KAMBkTej1Hm62HTw==",
       "dev": true,
       "requires": {
         "flat": "^4.1.0",
-        "lodash": "^4.17.11",
-        "yargs": "^12.0.5"
-      },
-      "dependencies": {
-        "get-caller-file": {
-          "version": "1.0.3",
-          "resolved": "https://registry.npmjs.org/get-caller-file/-/get-caller-file-1.0.3.tgz",
-          "integrity": "sha512-3t6rVToeoZfYSGd8YoLFR2DJkiQrIiUrGcjvFX2mDw3bn6k2OtwHN0TNCLbBO+w8qTvimhDkv+LSscbJY1vE6w==",
-          "dev": true
-        },
-        "require-main-filename": {
-          "version": "1.0.1",
-          "resolved": "https://registry.npmjs.org/require-main-filename/-/require-main-filename-1.0.1.tgz",
-          "integrity": "sha1-l/cXtp1IeE9fUmpsWqj/3aBVpNE=",
-          "dev": true
-        },
-        "yargs": {
-          "version": "12.0.5",
-          "resolved": "https://registry.npmjs.org/yargs/-/yargs-12.0.5.tgz",
-          "integrity": "sha512-Lhz8TLaYnxq/2ObqHDql8dX8CJi97oHxrjUcYtzKbbykPtVW9WB+poxI+NM2UIzsMgNCZTIf0AQwsjK5yMAqZw==",
-          "dev": true,
-          "requires": {
-            "cliui": "^4.0.0",
-            "decamelize": "^1.2.0",
-            "find-up": "^3.0.0",
-            "get-caller-file": "^1.0.1",
-            "os-locale": "^3.0.0",
-            "require-directory": "^2.1.1",
-            "require-main-filename": "^1.0.1",
-            "set-blocking": "^2.0.0",
-            "string-width": "^2.0.0",
-            "which-module": "^2.0.0",
-            "y18n": "^3.2.1 || ^4.0.0",
-            "yargs-parser": "^11.1.1"
-          }
-        },
-        "yargs-parser": {
-          "version": "11.1.1",
-          "resolved": "https://registry.npmjs.org/yargs-parser/-/yargs-parser-11.1.1.tgz",
-          "integrity": "sha512-C6kB/WJDiaxONLJQnF8ccx9SEeoTTLek8RVbaOIsrAUS8VrBEXfmeSnCZxygc+XC2sNMBIwOOnfcxiynjHsVSQ==",
-          "dev": true,
-          "requires": {
-            "camelcase": "^5.0.0",
-            "decamelize": "^1.2.0"
-          }
-        }
+        "lodash": "^4.17.15",
+        "yargs": "^13.3.0"
       }
     }
   }
diff --git a/package.json b/package.json
index 82b1fa6be..93f37fdef 100644
--- a/package.json
+++ b/package.json
@@ -22,6 +22,18 @@
     {
       "name": "Daniel Friedman",
       "url": "https://github.com/dan-f/"
+    },
+    {
+      "name": "Cénotélie",
+      "url": "https://github.com/cenotelie/"
+    },
+    {
+      "name": "Joep Meindertsma",
+      "url": "https://github.com/joepio/"
+    },
+    {
+      "name": "Thom van Kalkeren",
+      "url": "https://github.com/fletcher91/"
     }
   ],
   "license": "MIT",
@@ -43,20 +55,22 @@
   "devDependencies": {
     "@babel/cli": "^7.5.5",
     "@babel/core": "^7.5.5",
+    "@babel/plugin-proposal-class-properties": "^7.7.4",
     "@babel/plugin-transform-runtime": "^7.5.5",
     "@babel/preset-env": "^7.5.5",
     "@babel/preset-typescript": "^7.6.0",
     "@babel/register": "^7.5.5",
     "@types/chai": "^4.2.3",
+    "@types/dirty-chai": "^2.0.2",
     "@types/express": "^4.17.1",
+    "@types/jsonld": "^1.5.0",
     "@types/mocha": "^5.2.7",
     "babel-loader": "^8.0.6",
     "chai": "^4.2.0",
     "diff": "^4.0.1",
     "dirty-chai": "^2.0.1",
     "fs-grep": "^0.0.5",
-    "jsdoc": "^3.6.3",
-    "mocha": "^6.2.0",
+    "mocha": "^6.2.2",
     "nock": "^10.0.6",
     "node-fetch": "^2.6.0",
     "node-mkdirp": "0.0.1",
@@ -64,7 +78,8 @@
     "sinon": "^7.4.1",
     "sinon-chai": "^3.3.0",
     "source-map-loader": "^0.2.4",
-    "typescript": "^3.6.3",
+    "typedoc": "^0.15.3",
+    "typescript": "^3.7.2",
     "webpack": "^4.39.2",
     "webpack-cli": "^3.3.6",
     "webpack-dev-server": "^3.8.0",
@@ -74,8 +89,8 @@
     "build": "babel src --extensions \".ts,.js\" -d lib",
     "build:browser": "webpack --progress",
     "build:types": "tsc --emitDeclarationOnly -d --declarationDir lib --allowJs false",
-    "doc": "rm -r doc ; jsdoc -d doc README.md src/*.js",
-    "prepare": "npm run build && npm run build:browser",
+    "doc": "rm -r doc ; typedoc",
+    "prepare": "npm run build && npm run build:types && npm run build:browser",
     "start": "webpack-dev-server --https --port 4800",
     "test": "npm run test:unit && npm run test:serialize",
     "test:clean": "rimraf tests/serialize/,*",
@@ -94,7 +109,7 @@
     "test:serialize:11": "cd ./tests/serialize && node ./data.js -in=structures.n3 -format=application/rdf+xml  -out=,structures.xml && node diff ,structures.xml t11-ref.xml",
     "test:serialize:12": "cd ./tests/serialize && node ./data.js -in=structures.n3 -format=text/turtle -out=,structures.ttl && node diff ,structures.ttl t12-ref.ttl",
     "test:serialize:13": "cd ./tests/serialize && node ./data.js -in=structures.n3 -format=application/n-triples -out=,structures.nt && node ./data.js -format=application/n-triples -in=,structures.nt -format=text/turtle -out=,structures.nt.ttl && node diff ,structures.nt.ttl t13-ref.ttl",
-    "test:unit": "mocha --growl --require ./tests/babel-register.js tests/unit/**-test.js",
+    "test:unit": "mocha --growl --require ./tests/babel-register.js tests/unit/**-test.*",
     "test:unit:egp": "mocha --require ./tests/babel-register.js tests/unit/fetcher-egp-test.js",
     "test:unit:dev": "mocha --watch --growl --require ./tests/babel-register.js tests/unit/**-test.js"
   },
diff --git a/reference/fetcher-classes.js b/reference/fetcher-classes.js
index 9f11f47b6..91aebab57 100644
--- a/reference/fetcher-classes.js
+++ b/reference/fetcher-classes.js
@@ -1,8 +1,7 @@
-import { isNamedNode } from '../src/util'
+import { isNamedNode } from './utils/terms'
 
 const log = require('./log')
 const N3Parser = require('./n3parser')
-const NamedNode = require('./named-node')
 const Namespace = require('./namespace')
 const rdfParse = require('./parse')
 const parseRDFaDOM = require('./rdfaparser').parseRDFaDOM
diff --git a/src/blank-node.js b/src/blank-node.js
deleted file mode 100644
index 40aaffa36..000000000
--- a/src/blank-node.js
+++ /dev/null
@@ -1,65 +0,0 @@
-'use strict'
-import ClassOrder from './class-order'
-import Node from './node-internal'
-
-export default class BlankNode extends Node {
-  constructor (id) {
-    super()
-    this.termType = BlankNode.termType
-
-    if (id) {
-      if (typeof id !== 'string') {
-        console.log('Bad blank id:', id)
-        throw new Error('Bad id argument to new blank node: ' + id)
-      }
-      if (id.includes('#')) {
-        // Is a URI with hash fragment
-        let fragments = id.split('#')
-        id = fragments[fragments.length - 1]
-      }
-      this.id = id
-      // this.id = '' + BlankNode.nextId++
-    } else {
-      this.id = 'n' + BlankNode.nextId++
-    }
-
-    this.value = this.id
-  }
-
-  compareTerm (other) {
-    if (this.classOrder < other.classOrder) {
-      return -1
-    }
-    if (this.classOrder > other.classOrder) {
-      return +1
-    }
-    if (this.id < other.id) {
-      return -1
-    }
-    if (this.id > other.id) {
-      return +1
-    }
-    return 0
-  }
-
-  copy (formula) { // depends on the formula
-    var bnodeNew = new BlankNode()
-    formula.copyTo(this, bnodeNew)
-    return bnodeNew
-  }
-
-  toCanonical () {
-    return '_:' + this.value
-  }
-
-  toString () {
-    return BlankNode.NTAnonymousNodePrefix + this.id
-  }
-}
-
-BlankNode.nextId = 0
-BlankNode.termType = 'BlankNode'
-BlankNode.NTAnonymousNodePrefix = '_:'
-BlankNode.prototype.classOrder = ClassOrder['BlankNode']
-BlankNode.prototype.isBlank = 1
-BlankNode.prototype.isVar = 1
diff --git a/src/blank-node.ts b/src/blank-node.ts
new file mode 100644
index 000000000..5c409d95a
--- /dev/null
+++ b/src/blank-node.ts
@@ -0,0 +1,101 @@
+import ClassOrder from './class-order'
+import Node from './node-internal'
+import IndexedFormula from './store'
+import { BlankNodeTermType } from './types'
+import { BlankNode as TFBlankNode } from './tf-types'
+
+/**
+ * An RDF blank node is a Node without a URI
+ * @link https://rdf.js.org/data-model-spec/#blanknode-interface
+ */
+export default class BlankNode extends Node implements TFBlankNode {
+  termType: typeof BlankNodeTermType = BlankNodeTermType;
+  /**
+   * The next unique identifier for blank nodes
+   */
+  static nextId: number = 0;
+  static NTAnonymousNodePrefix: '_:' = '_:'
+
+  private static getId (id: string | unknown): string {
+    if (id) {
+      if (typeof id !== 'string') {
+        console.log('Bad blank id:', id)
+        throw new Error('Bad id argument to new blank node: ' + id)
+      }
+
+      if (id.includes('#')) {
+        // Is a URI with hash fragment
+        let fragments = id.split('#')
+        return fragments[fragments.length - 1]
+      }
+
+      return id
+    }
+
+    return 'n' + BlankNode.nextId++
+  }
+
+  classOrder = ClassOrder.BlankNode
+  /** Whether this is a blank node */
+  isBlank: number = 1
+  /**
+   * This type of node is a variable.
+   *
+   * Note that the existence of this property already indicates that it is a variable.
+   */
+  isVar = 1
+
+  /**
+   * Initializes this node
+   * @param [id] The identifier for the blank node
+   */
+  constructor (id?: string | unknown) {
+    super(BlankNode.getId(id))
+  }
+
+  /**
+   * The identifier for the blank node
+   * @deprecated use [[value]] instead.
+   */
+  public get id (): string {
+    return this.value
+  }
+
+  public set id (value: string) {
+    this.value = value
+  }
+
+  compareTerm (other: BlankNode): number {
+    if (this.classOrder < other.classOrder) {
+      return -1
+    }
+    if (this.classOrder > other.classOrder) {
+      return +1
+    }
+    if (this.id < other.id) {
+      return -1
+    }
+    if (this.id > other.id) {
+      return +1
+    }
+    return 0
+  }
+
+  /**
+   * Gets a copy of this blank node in the specified formula
+   * @param formula The formula
+   */
+  copy (formula: IndexedFormula): BlankNode { // depends on the formula
+    var bnodeNew = new BlankNode()
+    formula.copyTo(this, bnodeNew)
+    return bnodeNew
+  }
+
+  toCanonical () {
+    return BlankNode.NTAnonymousNodePrefix + this.value
+  }
+
+  toString () {
+    return BlankNode.NTAnonymousNodePrefix + this.id
+  }
+}
diff --git a/src/class-order.js b/src/class-order.ts
similarity index 50%
rename from src/class-order.js
rename to src/class-order.ts
index f2529983e..d614b56e5 100644
--- a/src/class-order.js
+++ b/src/class-order.ts
@@ -1,4 +1,9 @@
-export default {
+/**
+* Class orders
+*/
+const ClassOrder: {
+  [id: string]: number;
+} = {
   'Literal': 1,
   'Collection': 3,
   'Graph': 4,
@@ -6,3 +11,5 @@ export default {
   'BlankNode': 6,
   'Variable': 7
 }
+
+export default ClassOrder
diff --git a/src/collection.js b/src/collection.js
deleted file mode 100644
index 00ad37c67..000000000
--- a/src/collection.js
+++ /dev/null
@@ -1,51 +0,0 @@
-'use strict'
-import BlankNode from './blank-node'
-import ClassOrder from './class-order'
-import Node from './node-internal'
-
-export default class Collection extends Node {
-  constructor (initial) {
-    super()
-    this.termType = Collection.termType
-    this.id = BlankNode.nextId++
-    this.elements = []
-    this.closed = false
-    if (initial && initial.length > 0) {
-      initial.forEach(element => {
-        this.elements.push(Node.fromValue(element))
-      })
-    }
-  }
-  append (element) {
-    return this.elements.push(element)
-  }
-  close () {
-    this.closed = true
-    return this.closed
-  }
-  shift () {
-    return this.elements.shift()
-  }
-  substitute (bindings) {
-    var elementsCopy = this.elements.map(function (ea) {
-      ea.substitute(bindings)
-    })
-    return new Collection(elementsCopy)
-  }
-  toNT () {
-    return Collection.toNT(this)
-  }
-  static toNT (collection) {
-    return BlankNode.NTAnonymousNodePrefix + collection.id
-  }
-  toString () {
-    return '(' + this.elements.join(' ') + ')'
-  }
-  unshift (element) {
-    return this.elements.unshift(element)
-  }
-}
-Collection.termType = 'Collection'
-Collection.prototype.classOrder = ClassOrder['Collection']
-Collection.prototype.compareTerm = BlankNode.prototype.compareTerm
-Collection.prototype.isVar = 0
diff --git a/src/collection.ts b/src/collection.ts
new file mode 100644
index 000000000..58278db90
--- /dev/null
+++ b/src/collection.ts
@@ -0,0 +1,133 @@
+import RdflibBlankNode from './blank-node'
+import ClassOrder from './class-order'
+import Literal from './literal'
+import Node from './node-internal'
+import {
+  Bindings,
+  CollectionTermType,
+  FromValueReturns,
+  ValueType
+} from './types'
+import Variable from './variable'
+import { isTerm } from './utils/terms'
+import { Term } from './tf-types'
+
+/**
+ * Creates an RDF Node from a native javascript value.
+ * RDF Nodes are returned unchanged, undefined returned as itself.
+ * Arrays return Collections.
+ * Strings, numbers and booleans return Literals.
+ * @param value {Node|Date|String|Number|Boolean|Undefined}
+ * @return {Node|Collection}
+ */
+export function fromValue <T extends FromValueReturns<C> = any, C extends Node = any>(value: ValueType): T {
+  if (typeof value === 'undefined' || value === null) {
+    return value as T
+  }
+
+  if (isTerm(value)) {  // a Node subclass or a Collection
+    return value as T
+  }
+
+  if (Array.isArray(value)) {
+    return new Collection<C>(value) as T
+  }
+
+  return Literal.fromValue<any>(value)
+}
+
+/**
+ * A collection of other RDF nodes
+ *
+ * Use generic T to control the contents of the array.
+ */
+export default class Collection<
+  T extends Node = Node | RdflibBlankNode | Collection<any> | Literal | Variable
+> extends Node implements Term {
+  static termType: typeof CollectionTermType = CollectionTermType
+  termType: typeof CollectionTermType = CollectionTermType
+
+  classOrder = ClassOrder.Collection
+  closed: boolean = false
+  compareTerm = RdflibBlankNode.prototype.compareTerm
+  /**
+   * The nodes in this collection
+   */
+  elements: T[] = []
+  isVar = 0
+
+  constructor (initial?: ReadonlyArray<ValueType>) {
+    super((RdflibBlankNode.nextId++).toString())
+
+    if (initial && initial.length > 0) {
+      initial.forEach(element => {
+        this.elements.push(fromValue<T>(element))
+      })
+    }
+  }
+
+  public get id (): string {
+    return this.value
+  }
+
+  public set id (value) {
+    this.value = value
+  }
+
+  /**
+   * Appends an element to this collection
+   * @param element - The new element
+   */
+  append (element: T): number {
+    return this.elements.push(element)
+  }
+
+  /**
+   * Closes this collection
+   */
+  close (): boolean {
+    this.closed = true
+    return this.closed
+  }
+
+  /**
+   * Removes the first element from the collection (and return it)
+   */
+  shift (): T | undefined {
+    return this.elements.shift()
+  }
+
+  /**
+   * Creates a new Collection with the substituting bindings applied
+   * @param bindings - The bindings to substitute
+   */
+  substitute (bindings: Bindings) {
+    const elementsCopy = this.elements.map((ea) => ea.substitute(bindings))
+
+    return new Collection(elementsCopy)
+  }
+
+  toNT () {
+    return Collection.toNT(this)
+  }
+
+  static toNT (collection) {
+    return RdflibBlankNode.NTAnonymousNodePrefix + collection.id
+  }
+
+  /**
+   * Serializes the collection to a string.
+   * Surrounded by (parentheses) and separated by spaces.
+   */
+  toString () {
+    return '(' + this.elements.join(' ') + ')'
+  }
+
+  /**
+   * Prepends the specified element to the collection's front
+   * @param element - The element to prepend
+   */
+  unshift (element: T): number {
+    return this.elements.unshift(element)
+  }
+}
diff --git a/src/data-factory-internal.js b/src/data-factory-internal.js
deleted file mode 100644
index 59171e970..000000000
--- a/src/data-factory-internal.js
+++ /dev/null
@@ -1,91 +0,0 @@
-import BlankNode from './blank-node'
-import Literal from './literal'
-import NamedNode from './named-node'
-import Statement from './statement'
-import Variable from './variable'
-
-export const defaultGraphURI = 'chrome:theSession'
-const defaultGraphNode = new NamedNode(defaultGraphURI)
-
-function blankNode (value) {
-  return new BlankNode(value)
-}
-
-function defaultGraph () {
-  return defaultGraphNode
-}
-
-/**
- * Generates a unique identifier for the object.
- *
- * Equivalent to {Term.hashString}
- */
-function id (term) {
-  if (!term) {
-    return term
-  }
-  if (Object.prototype.hasOwnProperty.call(term, "id") && typeof term.id === "function") {
-    return term.id()
-  }
-  if (Object.prototype.hasOwnProperty.call(term, "hashString")) {
-    return term.hashString()
-  }
-
-  switch (term.termType) {
-    case "NamedNode":
-      return '<' + term.value + '>'
-    case "BlankNode":
-      return '_:' + term.value
-    case "Literal":
-      return Literal.toNT(term)
-    case "Variable":
-      return Variable.toString(term)
-    default:
-      return undefined
-  }
-}
-
-function literal (value, languageOrDatatype) {
-  if (typeof value !== "string" && !languageOrDatatype) {
-    return Literal.fromValue(value)
-  }
-
-  const strValue = typeof value === 'string' ? value : '' + value
-  if (typeof languageOrDatatype === 'string') {
-    if (languageOrDatatype.indexOf(':') === -1) {
-      return new Literal(strValue, languageOrDatatype)
-    } else {
-      return new Literal(strValue, null, namedNode(languageOrDatatype))
-    }
-  } else {
-    return new Literal(strValue, null, languageOrDatatype)
-  }
-}
-function namedNode (value) {
-  return new NamedNode(value)
-}
-function quad (subject, predicate, object, graph) {
-  graph = graph || defaultGraph()
-  return new Statement(subject, predicate, object, graph)
-}
-function variable (name) {
-  return new Variable(name)
-}
-
-/** Contains the factory methods as defined in the spec, plus id */
-export default {
-  blankNode,
-  defaultGraph,
-  literal,
-  namedNode,
-  quad,
-  variable,
-  id,
-  supports: {
-    COLLECTIONS: false,
-    DEFAULT_GRAPH_TYPE: true,
-    EQUALS_METHOD: true,
-    NODE_LOOKUP: false,
-    VARIABLE_TYPE: true,
-  }
-}
diff --git a/src/data-factory.js b/src/data-factory.js
deleted file mode 100644
index 73293f38f..000000000
--- a/src/data-factory.js
+++ /dev/null
@@ -1,72 +0,0 @@
-'use strict'
-import Collection from './collection'
-import CanonicalDataFactory from './data-factory-internal'
-import Fetcher from './fetcher'
-import Literal from './literal'
-import Statement from './statement'
-import IndexedFormula from './store'
-
-/**
- * Data factory which also supports Collections
- *
- * Necessary for preventing circular dependencies.
- */
-const ExtendedTermFactory = {
-  ...CanonicalDataFactory,
-  collection,
-  id,
-  supports: {
-    COLLECTIONS: true,
-    DEFAULT_GRAPH_TYPE: true,
-    EQUALS_METHOD: true,
-    NODE_LOOKUP: false,
-    VARIABLE_TYPE: true,
-  }
-}
-
-/** Full RDFLib.js Data Factory */
-const DataFactory = {
-  ...ExtendedTermFactory,
-  fetcher,
-  graph,
-  lit,
-  st,
-  triple,
-}
-export default DataFactory
-
-function id (term) {
-  if (!term) {
-    return term
-  }
-  if (Object.prototype.hasOwnProperty.call(term, "id") && typeof term.id === "function") {
-    return term.id()
-  }
-  if (Object.prototype.hasOwnProperty.call(term, "hashString")) {
-    return term.hashString()
-  }
-
-  if (term.termType === "Collection") {
-    Collection.toNT(term)
-  }
-
-  return CanonicalDataFactory.id(term)
-}
-function collection (elements) {
-  return new Collection(elements)
-}
-function fetcher (store, options) {
-  return new Fetcher(store, options)
-}
-function graph (features = undefined, opts = undefined) {
-  return new IndexedFormula(features, opts || { rdfFactory: ExtendedTermFactory })
-}
-function lit (val, lang, dt) {
-  return new Literal('' + val, lang, dt)
-}
-function st (subject, predicate, object, graph) {
-  return new Statement(subject, predicate, object, graph)
-}
-function triple (subject, predicate, object) {
-  return CanonicalDataFactory.quad(subject, predicate, object)
-}
diff --git a/src/default-graph.js b/src/default-graph.js
deleted file mode 100644
index a45cd7af5..000000000
--- a/src/default-graph.js
+++ /dev/null
@@ -1,13 +0,0 @@
-'use strict'
-import Node from './node'
-
-export default class DefaultGraph extends Node {
-  constructor () {
-    super()
-    this.termType = 'DefaultGraph'
-    this.value = ''
-  }
-  toCanonical () {
-    return this.value
-  }
-}
diff --git a/src/default-graph.ts b/src/default-graph.ts
new file mode 100644
index 000000000..c4fbd7ea7
--- /dev/null
+++ b/src/default-graph.ts
@@ -0,0 +1,16 @@
+import Node from './node-internal'
+import { DefaultGraphTermType } from './types'
+import { DefaultGraph as TFDefaultGraph } from './tf-types'
+
+/** The RDF default graph */
+export default class DefaultGraph extends Node implements TFDefaultGraph {
+  termType: typeof DefaultGraphTermType = DefaultGraphTermType;
+
+  constructor () {
+    super('')
+  }
+
+  toCanonical () {
+    return this.value
+  }
+}
diff --git a/src/empty.js b/src/empty.js
deleted file mode 100644
index a24ee039d..000000000
--- a/src/empty.js
+++ /dev/null
@@ -1,16 +0,0 @@
-'use strict'
-import Node from './node'
-
-/**
- * Singleton subclass of an empty Collection.
- */
-export default class Empty extends Node {
-  constructor () {
-    super()
-    this.termType = Empty.termType
-  }
-  toString () {
-    return '()'
-  }
-}
-Empty.termType = 'empty'
diff --git a/src/empty.ts b/src/empty.ts
new file mode 100644
index 000000000..3a3e3c8d3
--- /dev/null
+++ b/src/empty.ts
@@ -0,0 +1,18 @@
+import Node from './node-internal'
+import { EmptyTermType } from './types'
+import { Term } from './tf-types'
+
+/**
+* An empty node
+*/
+export default class Empty extends Node implements Term {
+  termType: typeof EmptyTermType = EmptyTermType
+
+  constructor () {
+    super('')
+  }
+
+  toString () {
+    return '()'
+  }
+}
diff --git a/src/factories/canonical-data-factory.ts b/src/factories/canonical-data-factory.ts
new file mode 100644
index 000000000..de90b8f1b
--- /dev/null
+++ b/src/factories/canonical-data-factory.ts
@@ -0,0 +1,215 @@
+import BlankNode from '../blank-node'
+import Literal from '../literal'
+import NamedNode from '../named-node'
+import Statement from '../statement'
+import Variable from '../variable'
+import {
+  SubjectType,
+  PredicateType,
+  ObjectType,
+  GraphType,
+  EmptyTermType,
+  DefaultGraphTermType,
+  VariableTermType,
+  BlankNodeTermType,
+  LiteralTermType,
+  NamedNodeTermType,
+} from '../types'
+import { defaultGraphNode } from '../utils/default-graph-uri'
+import {
+  Comparable,
+  DataFactory,
+  DefaultFactoryTypes,
+  Feature,
+} from './factory-types'
+import { isQuad, isTerm } from '../utils/terms'
+import { NamedNode as TFNamedNode, Quad, Term } from '../tf-types'
+
+export { defaultGraphURI } from '../utils/default-graph-uri'
+
+/**
+ * Gets the default graph
+ */
+export function defaultGraph(): NamedNode {
+  return defaultGraphNode
+}
+
+/** A basic internal RDFlib datafactory, which does not support Collections  */
+const CanonicalDataFactory: DataFactory = {
+
+  supports: {
+    [Feature.collections]: false,
+    [Feature.defaultGraphType]: false,
+    [Feature.equalsMethod]: true,
+    [Feature.identity]: false,
+    [Feature.id]: true,
+    [Feature.reversibleId]: false,
+    [Feature.variableType]: true,
+  },
+
+  /**
+   * Creates a new blank node
+   * @param value - The blank node's identifier
+   */
+  blankNode(value?: string): BlankNode {
+    return new BlankNode(value)
+  },
+
+  defaultGraph,
+
+  /**
+   * Compares to (rdf) objects for equality.
+   */
+  equals(a: Comparable, b: Comparable): boolean {
+    if (a === b || !a || !b) {
+      return true
+    }
+
+    if (isQuad(a) || isQuad(b)) {
+      if (isQuad(a) && isQuad(b)) {
+        return (
+          this.equals(a.subject, b.subject) &&
+          this.equals(a.predicate, b.predicate) &&
+          this.equals(a.object, b.object) &&
+          this.equals(a.graph, b.graph)
+        )
+      }
+
+      return false
+    }
+
+    if (isTerm(a) && isTerm(b)) {
+      return this.id(a) === this.id(b)
+    }
+
+    return false
+  },
+
+  /**
+   * Generates a uniquely identifiably *idempotent* string for the given {term}.
+   *
+   * Equivalent to [[Term.hashString]]
+   *
+   * @example Use this to associate data with a term in an object
+   *   { obj[id(term)] = "myData" }
+   */
+  id (term: Term | Statement | undefined): string {
+    if (!term) {
+      return 'undefined'
+    }
+
+    if (isQuad(term)) {
+      return this.quadToNQ(term)
+    }
+
+    switch (term.termType) {
+      case DefaultGraphTermType:
+        return 'defaultGraph'
+      case VariableTermType:
+        return Variable.toString(term)
+      default:
+        const nq = this.termToNQ(term)
+        if (nq) {
+          return nq
+        }
+
+        throw new Error(`Can't id term with type '${term.termType}'`)
+    }
+  },
+
+  isQuad (obj: any): obj is Statement {
+    return obj instanceof Statement
+  },
+
+  /**
+   * Creates a new literal node. Does some JS literal parsing for ease of use.
+   * @param value - The lexical value
+   * @param languageOrDatatype - Either the language or the datatype
+   */
+  literal(
+    value: string | number | boolean | Date,
+    languageOrDatatype?: string | TFNamedNode
+  ): Literal {
+    if (typeof value !== "string" && !languageOrDatatype) {
+      return Literal.fromValue(value)
+    }
+
+    const strValue = typeof value === 'string' ? value : '' + value
+    if (typeof languageOrDatatype === 'string') {
+      if (languageOrDatatype.indexOf(':') === -1) {
+        return new Literal(strValue, languageOrDatatype)
+      } else {
+        return new Literal(strValue, null, this.namedNode(languageOrDatatype))
+      }
+    } else {
+      return new Literal(strValue, null, languageOrDatatype)
+    }
+  },
+
+  /**
+   * Creates a new named node
+   * @param value - The new named node
+   */
+  namedNode(value: string): NamedNode {
+    return new NamedNode(value)
+  },
+
+  /**
+   * Creates a new statement
+   * @param subject - The subject
+   * @param predicate - The predicate
+   * @param object - The object
+   * @param graph - The containing graph
+   */
+  quad(
+    subject: Term | SubjectType,
+    predicate: Term | PredicateType,
+    object: Term | ObjectType,
+    graph?: Term | GraphType
+  ): Statement {
+    graph = graph || defaultGraph()
+    return new Statement(subject, predicate, object, graph)
+  },
+
+  quadToNQ(q: Statement | Quad): string {
+    return `${this.termToNQ(q.subject)} ${this.termToNQ(q.predicate)} ${this.termToNQ(q.object)} ${this.termToNQ(q.graph)} .`;
+  },
+
+  /** Stringify a {term} to n-quads serialization. */
+  termToNQ(term: Term): string {
+    switch (term.termType) {
+      case BlankNodeTermType:
+        return '_:' + term.value
+      case DefaultGraphTermType:
+        return ''
+      case EmptyTermType:
+        return '<http://www.w3.org/1999/02/22-rdf-syntax-ns#nil>'
+      case LiteralTermType:
+        return Literal.toNT(term as Literal)
+      case NamedNodeTermType:
+        return '<' + term.value + '>'
+      default:
+        throw new Error(`Can't serialize nonstandard term type (was '${term.termType}')`)
+    }
+  },
+
+  /** Convert an rdf object (term or quad) to n-quads serialization. */
+  toNQ (term: Term | (DefaultFactoryTypes & Variable)): string {
+    if (this.isQuad(term)) {
+      return this.quadToNQ(term);
+    }
+
+    return this.termToNQ(term);
+  },
+
+  /**
+   * Creates a new variable
+   * @param name - The name for the variable
+   */
+  variable(name?: string): Variable {
+    return new Variable(name)
+  },
+}
+
+/** Contains the factory methods as defined in the spec, plus id */
+export default CanonicalDataFactory
diff --git a/src/factories/extended-term-factory.ts b/src/factories/extended-term-factory.ts
new file mode 100644
index 000000000..b99234a36
--- /dev/null
+++ b/src/factories/extended-term-factory.ts
@@ -0,0 +1,61 @@
+import Collection from '../collection'
+import CanonicalDataFactory from './canonical-data-factory'
+import { ValueType, CollectionTermType } from '../types'
+import { DataFactory, DefaultFactoryTypes, Feature, Indexable } from './factory-types'
+import { isCollection, isVariable } from '../utils/terms'
+import Variable from '../variable'
+import { Term } from '../tf-types'
+
+interface CollectionFactory extends DataFactory {
+  collection(elements: ReadonlyArray<ValueType>): Collection
+}
+
+/**
+ * Data factory which also supports Collections
+ *
+ * Necessary for preventing circular dependencies.
+ */
+const ExtendedTermFactory: CollectionFactory = {
+  ...CanonicalDataFactory,
+
+  supports: {
+    [Feature.collections]: true,
+    [Feature.defaultGraphType]: false,
+    [Feature.equalsMethod]: true,
+    [Feature.identity]: false,
+    [Feature.id]: true,
+    [Feature.reversibleId]: false,
+    [Feature.variableType]: true,
+  },
+
+  /**
+   * Creates a new collection
+   * @param elements - The initial element
+   */
+  collection (elements: ReadonlyArray<ValueType>): Collection {
+    return new Collection(elements)
+  },
+
+  id (term: Term | DefaultFactoryTypes): Indexable {
+    if (isCollection(term)) {
+      return `( ${term.elements.map((e) => {
+        return this.id(e) }).join(', ')} )`
+    }
+
+    if (isVariable(term)) {
+      return Variable.toString(term)
+    }
+
+    return CanonicalDataFactory.id(term)
+  },
+
+  termToNQ (term: Term): string {
+    if (term.termType === CollectionTermType) {
+      return Collection.toNT(term)
+    }
+
+    return CanonicalDataFactory.termToNQ(term)
+  }
+}
+
+export default ExtendedTermFactory
diff --git a/src/factories/factory-types.ts b/src/factories/factory-types.ts
new file mode 100644
index 000000000..1b663efc1
--- /dev/null
+++ b/src/factories/factory-types.ts
@@ -0,0 +1,95 @@
+import Literal from '../literal'
+import Statement from '../statement'
+import NamedNode from '../named-node'
+import BlankNode from '../blank-node'
+import Variable from '../variable'
+import {
+  BlankNode as TFBlankNode,
+  RdfJsDataFactory,
+  Literal as TFLiteral,
+  NamedNode as TFNamedNode,
+  Quad,
+  Term,
+  Variable as TFVariable,
+} from '../tf-types'
+
+export type Comparable = Term | TFNamedNode | TFBlankNode | TFLiteral | Quad | undefined | null
+
+export type DefaultFactoryTypes = NamedNode | BlankNode | Literal | Variable | Statement
+
+export type Indexable = number | string
+
+export type Namespace = (term:string) => TFNamedNode
+
+/** A set of features that may be supported by a Data Factory */
+export type SupportTable = Record<Feature, boolean>
+
+export type TFIDFactoryTypes = TFNamedNode | TFBlankNode | TFLiteral | Quad | TFVariable | Term
+
+export enum Feature {
+  /** Whether the factory supports termType:Collection terms */
+  collections = "COLLECTIONS",
+  /** Whether the factory supports termType:DefaultGraph terms */
+  defaultGraphType = "DEFAULT_GRAPH_TYPE",
+  /** Whether the factory supports equals on produced instances */
+  equalsMethod = "EQUALS_METHOD",
+  /** Whether the factory can create a unique idempotent identifier for the given term. */
+  id = "ID",
+  /**
+   * Whether the factory will return the same instance for subsequent calls.
+   * This implies `===`, which means methods like `indexOf` can be used.
+   */
+  identity = "IDENTITY",
+  /** Whether the factory supports mapping ids back to instances (should adhere to the identity setting) */
+  reversibleId = "REVERSIBLE_ID",
+  /** Whether the factory supports termType:Variable terms */
+  variableType = "VARIABLE_TYPE",
+}
+
+/**
+ * Defines a DataFactory as used in rdflib, based on the RDF/JS: Data model specification,
+ * but with additional extensions
+ *
+ * bnIndex is optional but useful.
+ */
+export interface DataFactory<
+  FactoryTypes = DefaultFactoryTypes,
+  IndexType = Indexable
+> extends RdfJsDataFactory {
+  /**
+   * BlankNode index
+   * @private
+  */
+  bnIndex?: number
+
+  supports: SupportTable
+
+  literal(value: string, languageOrDatatype?: string | TFNamedNode): Literal
+
+  isQuad(obj: any): obj is Statement
+
+  equals(a: Comparable, b: Comparable): boolean
+
+  toNQ(term: Term | FactoryTypes): string
+
+  quad(
+    subject: Term,
+    predicate: Term,
+    object: Term,
+    graph?: Term,
+  ): Statement;
+
+  quadToNQ(term: Statement | Quad): string
+
+  termToNQ(term: Term): string
+
+  /**
+   * Generates a unique session-idempotent identifier for the given object.
+   *
+   * @example NQ serialization (reversible from value)
+   * @example MD5 hash of termType + value (irreversible from value, map needed)
+   *
+   * @return {Indexable} A unique value which must also be a valid JS object key type.
+   */
+  id(obj: Term | FactoryTypes): IndexType
+}
diff --git a/src/factories/rdflib-data-factory.ts b/src/factories/rdflib-data-factory.ts
new file mode 100644
index 000000000..7798d5e06
--- /dev/null
+++ b/src/factories/rdflib-data-factory.ts
@@ -0,0 +1,78 @@
+import {
+  IRDFlibDataFactory,
+  ObjectType,
+  PredicateType,
+  SubjectType,
+} from '../types'
+import Literal from '../literal'
+import Statement from '../statement'
+import IndexedFormula from '../store'
+import Fetcher from '../fetcher'
+import ExtendedTermFactory from './extended-term-factory'
+import { NamedNode, Term } from '../tf-types'
+
+/** Full RDFLib.js Data Factory */
+const RDFlibDataFactory: IRDFlibDataFactory = {
+  ...ExtendedTermFactory,
+
+  /**
+   * Creates a new fetcher
+   * @param store - The store to use
+   * @param options - The options
+   */
+  fetcher (store: IndexedFormula, options: any): Fetcher {
+    return new Fetcher(store, options)
+  },
+
+  /**
+   * Creates a new graph (store)
+   */
+  graph (features = undefined, opts = undefined): IndexedFormula {
+    return new IndexedFormula(features, opts || {rdfFactory: ExtendedTermFactory})
+  },
+
+  /**
+   * Creates a new literal node
+   * @param val The lexical value
+   * @param lang The language
+   * @param dt The datatype
+   * @deprecated use [[literal]] with the second and third argument combined
+   */
+  lit (val: string, lang?: string, dt?: NamedNode): Literal {
+    return this.literal('' + val, lang || dt)
+  },
+
+  /**
+   * Creates a new statement
+   * @param subject The subject
+   * @param predicate The predicate
+   * @param object The object
+   * @param graph The containing graph
+   * @deprecated use [[quad]] instead
+   */
+  st (
+    subject: Term,
+    predicate: Term,
+    object: Term,
+    graph?: Term
+  ): Statement {
+    return this.quad(subject, predicate, object, graph)
+  },
+
+  /**
+   * Creates a new statement
+   * @param subject The subject
+   * @param predicate The predicate
+   * @param object The object
+   * @deprecated use [[quad]] without the last argument instead
+   */
+  triple (
+    subject: SubjectType,
+    predicate: PredicateType,
+    object: ObjectType
+  ): Statement {
+    return this.quad(subject, predicate, object)
+  },
+}
+
+export default RDFlibDataFactory
diff --git a/src/fetcher.js b/src/fetcher.ts
similarity index 63%
rename from src/fetcher.js
rename to src/fetcher.ts
index 362908db4..c1c227c9f 100644
--- a/src/fetcher.js
+++ b/src/fetcher.ts
@@ -28,18 +28,32 @@
 import IndexedFormula from './store'
 import log from './log'
 import N3Parser from './n3parser'
-import NamedNode from './named-node'
+import RDFlibNamedNode from './named-node'
 import Namespace from './namespace'
 import rdfParse from './parse'
 import { parseRDFaDOM } from './rdfaparser'
 import RDFParser from './rdfxmlparser'
 import * as Uri from './uri'
-import { isNamedNode } from './util'
-import * as Util from './util'
+import { isCollection, isNamedNode} from './utils/terms'
+import * as Util from './utils-js'
 import serialize from './serialize'
 
+// @ts-ignore This is injected
 import { fetch as solidAuthCli } from 'solid-auth-cli'
+// @ts-ignore This is injected
 import { fetch as solidAuthClient } from 'solid-auth-client'
+import {
+  ContentType, TurtleContentType, RDFXMLContentType, XHTMLContentType
+} from './types'
+import { termValue } from './utils/termValue'
+import {
+  BlankNode,
+  RdfJsDataFactory,
+  Quad_Graph,
+  NamedNode,
+  Quad_Predicate,
+  Quad_Subject
+} from './tf-types'
 
 // This is a special fetch which does OIDC auth, catching 401 errors
 const fetch = typeof window === 'undefined' ? solidAuthCli : solidAuthClient
@@ -55,8 +69,8 @@ const Parsable = {
 
 // This is a minimal set to allow the use of damaged servers if necessary
 const CONTENT_TYPE_BY_EXT = {
-  'rdf': 'application/rdf+xml',
-  'owl': 'application/rdf+xml',
+  'rdf': RDFXMLContentType,
+  'owl': RDFXMLContentType,
   'n3': 'text/n3',
   'ttl': 'text/turtle',
   'nt': 'text/n3',
@@ -70,7 +84,7 @@ const CONTENT_TYPE_BY_EXT = {
 // make its own list and not rely on the prefixes used here,
 // and not be tempted to add to them, and them clash with those of another
 // application.
-const getNS = (factory) => {
+const getNS = (factory?: RdfJsDataFactory) => {
   return {
     link: Namespace('http://www.w3.org/2007/ont/link#', factory),
     http: Namespace('http://www.w3.org/2007/ont/http#', factory),
@@ -83,10 +97,117 @@ const getNS = (factory) => {
 }
 const ns = getNS()
 
+interface FetchError extends Error {
+  statusText?: string
+  status?: StatusValues
+  response?: ExtendedResponse
+}
+
+/** An extended interface of Response, since RDFlib.js adds some properties. */
+interface ExtendedResponse extends Response {
+  /** String representation of the Body */
+  responseText?: string
+  /** Identifier of the reqest */
+  req?: Quad_Subject
+  size?: number
+  timeout?: number
+  /** Used in UpdateManager.updateDav */
+  error?: string
+}
+
+/** tell typescript that a 'panes' child may exist on Window */
+declare global {
+  interface Window {
+    panes?: any
+  }
+}
+
+declare var $SolidTestEnvironment: {
+  localSiteMap?: any
+}
+
+type UserCallback = (
+  ok: boolean,
+  message: string,
+  response?: any
+) => void
+
+type HTTPMethods = 'GET' | 'PUT' | 'POST' | 'PATCH' | 'HEAD' | 'DELETE' | 'CONNECT' | 'TRACE' | 'OPTIONS'
+
+/** All valid inputs for initFetchOptions */
+type Options = Partial<AutoInitOptions>
+
+/** Initiated by initFetchOptions, which runs on load */
+interface AutoInitOptions extends RequestInit{
+  /** The used Fetch function */
+  fetch?: Fetch
+  /**
+   * Referring term, the resource which
+   * referred to this (for tracking bad links).
+   * The document in which this link was found.
+   */
+  referringTerm?: NamedNode
+  /** Provided content type (for writes) */
+  contentType?: string
+  /**
+   * Override the incoming header to
+   * force the data to be treated as this content-type (for reads)
+   */
+  forceContentType?: ContentType
+  /**
+   * Load the data even if loaded before.
+   * Also sets the `Cache-Control:` header to `no-cache`
+   */
+  force?: boolean
+  /**
+   * Original uri to preserve
+   * through proxying etc (`xhr.original`).
+   */
+  baseURI: string
+  /**
+   * Whether this request is a retry via
+   * a proxy (generally done from an error handler)
+   */
+  proxyUsed?: boolean
+  actualProxyURI?: string
+  /** flag for XHR/CORS etc */
+  withCredentials?: boolean
+  /** Before we parse new data, clear old, but only on status 200 responses */
+  clearPreviousData?: boolean
+  /** Prevents the addition of various metadata triples (about the fetch request) to the store*/
+  noMeta?: boolean
+  noRDFa?: boolean
+  handlers?: Handler[]
+  timeout?: number
+  method?: HTTPMethods
+  retriedWithNoCredentials?: boolean
+  requestedURI?: string
+  // Seems to be required in some functions, such as XHTML parse and RedirectToProxy
+  resource: Quad_Subject
+  /** The serialized resource in the body*/
+  // Used for storing metadata of requests
+  original: NamedNode
+  // Like requeststatus? Can contain text with error.
+  data?: string
+  // Probably an identifier for request?s
+  req: BlankNode
+  // Might be the same as Options.data
+  body?: string
+  headers: Headers
+  credentials?: 'include' | 'omit'
+}
+
 class Handler {
-  constructor (response, dom) {
+  // TODO: Document, type
+  response: ExtendedResponse
+  // TODO: Document, type
+  dom: Document
+  static pattern: RegExp
+
+  constructor (response: ExtendedResponse, dom?: Document) {
     this.response = response
-    this.dom = dom
+    // The type assertion operator here might need to be removed.
+    this.dom = dom!
   }
 }
 
@@ -95,13 +216,22 @@ class RDFXMLHandler extends Handler {
     return 'RDFXMLHandler'
   }
 
-  static register (fetcher) {
-    fetcher.mediatypes['application/rdf+xml'] = {
+  static register (fetcher: Fetcher) {
+    fetcher.mediatypes[RDFXMLContentType] = {
       'q': 0.9
     }
   }
 
-  parse (fetcher, responseText, options, response) {
+  parse (
+    fetcher: Fetcher,
+    /** An XML String */
+    responseText: String,
+    /** Requires .original */
+    options: {
+      original: Quad_Subject
+      req: Quad_Subject
+    } & Options,
+  ) {
     let kb = fetcher.store
     if (!this.dom) {
       this.dom = Util.parseXML(responseText)
@@ -110,11 +240,11 @@ class RDFXMLHandler extends Handler {
     if (root.nodeName === 'parsererror') { // Mozilla only See issue/issue110
       // have to fail the request
       return fetcher.failFetch(options, 'Badly formed XML in ' +
-        options.resource.uri, 'parse_error')
+        options.resource!.value, 'parse_error')
     }
     let parser = new RDFParser(kb)
     try {
-      parser.parse(this.dom, options.original.uri, options.original, response)
+      parser.parse(this.dom, options.original.value, options.original)
     } catch (err) {
       return fetcher.failFetch(options, 'Syntax error parsing RDF/XML! ' + err,
         'parse_error')
@@ -133,12 +263,19 @@ class XHTMLHandler extends Handler {
     return 'XHTMLHandler'
   }
 
-  static register (fetcher) {
-    fetcher.mediatypes['application/xhtml+xml'] = {}
+  static register (fetcher: Fetcher) {
+    fetcher.mediatypes[XHTMLContentType] = {}
   }
 
-  parse (fetcher, responseText, options, response) {
-    let relation, reverse
+  parse (
+    fetcher: Fetcher,
+    responseText: string,
+    options: {
+      resource: Quad_Subject
+      original: Quad_Subject
+    } & Options,
+  ): Promise<FetchError> | ExtendedResponse {
+    let relation, reverse: boolean
     if (!this.dom) {
       this.dom = Util.parseXML(responseText)
     }
@@ -147,7 +284,7 @@ class XHTMLHandler extends Handler {
     // dc:title
     let title = this.dom.getElementsByTagName('title')
     if (title.length > 0) {
-      kb.add(options.resource, ns.dc('title'), kb.literal(title[0].textContent),
+      kb.add(options.resource, ns.dc('title'), kb.rdfFactory.literal(title[0].textContent as string),
         options.resource)
       // log.info("Inferring title of " + xhr.resource)
     }
@@ -163,7 +300,7 @@ class XHTMLHandler extends Handler {
       }
       if (relation) {
         fetcher.linkData(options.original, relation,
-          links[x].getAttribute('href'), options.resource, reverse)
+          links[x].getAttribute('href') as string, options.resource, reverse)
       }
     }
 
@@ -171,9 +308,11 @@ class XHTMLHandler extends Handler {
     let scripts = this.dom.getElementsByTagName('script')
     for (let i = 0; i < scripts.length; i++) {
       let contentType = scripts[i].getAttribute('type')
-      if (Parsable[contentType]) {
-        rdfParse(scripts[i].textContent, kb, options.original.uri, contentType)
-        rdfParse(scripts[i].textContent, kb, options.original.uri, contentType)
+      if (Parsable[contentType!]) {
+        // @ts-ignore incompatibility between Store.add and Formula.add
+        rdfParse(scripts[i].textContent as string, kb, options.original.value, contentType)
+        // @ts-ignore incompatibility between Store.add and Formula.add
+        rdfParse(scripts[i].textContent as string, kb, options.original.value, contentType)
       }
     }
 
@@ -183,15 +322,15 @@ class XHTMLHandler extends Handler {
 
     if (!options.noRDFa && parseRDFaDOM) { // enable by default
       try {
-        parseRDFaDOM(this.dom, kb, options.original.uri)
+        parseRDFaDOM(this.dom, kb, options.original.value)
       } catch (err) {
         let msg = 'Error trying to parse ' + options.resource + ' as RDFa:\n' +
           err + ':\n' + err.stack
-        return fetcher.failFetch(options, msg, 'parse_error')
+        return fetcher.failFetch(options as AutoInitOptions, msg, 'parse_error')
       }
     }
 
-    return fetcher.doneFetch(options, this.response)
+    return fetcher.doneFetch(options as AutoInitOptions, this.response)
   }
 }
 XHTMLHandler.pattern = new RegExp('application/xhtml')
@@ -201,12 +340,20 @@ class XMLHandler extends Handler {
     return 'XMLHandler'
   }
 
-  static register (fetcher) {
+  static register (fetcher: Fetcher) {
     fetcher.mediatypes['text/xml'] = { 'q': 0.5 }
     fetcher.mediatypes['application/xml'] = { 'q': 0.5 }
   }
 
-  parse (fetcher, responseText, options, response) {
+  parse (
+    fetcher: Fetcher,
+    responseText: string,
+    options: {
+      original: Quad_Subject
+      req: BlankNode
+      resource: Quad_Subject
+    } & Options,
+  ): ExtendedResponse | Promise<FetchError> {
     let dom = Util.parseXML(responseText)
 
     // XML Semantics defined by root element namespace
@@ -223,7 +370,7 @@ class XMLHandler extends Handler {
             'Has XML root element in the RDF namespace, so assume RDF/XML.')
 
           let rdfHandler = new RDFXMLHandler(this.response, dom)
-          return rdfHandler.parse(fetcher, responseText, options, response)
+          return rdfHandler.parse(fetcher, responseText, options)
         }
 
         break
@@ -241,7 +388,7 @@ class XMLHandler extends Handler {
           'Has XHTML DOCTYPE. Switching to XHTML Handler.\n')
 
         let xhtmlHandler = new XHTMLHandler(this.response, dom)
-        return xhtmlHandler.parse(fetcher, responseText, options, response)
+        return xhtmlHandler.parse(fetcher, responseText, options)
       }
     }
 
@@ -254,7 +401,7 @@ class XMLHandler extends Handler {
           'Has a default namespace for ' + 'XHTML. Switching to XHTMLHandler.\n')
 
         let xhtmlHandler = new XHTMLHandler(this.response, dom)
-        return xhtmlHandler.parse(fetcher, responseText, options, response)
+        return xhtmlHandler.parse(fetcher, responseText, options)
       }
     }
 
@@ -275,13 +422,21 @@ class HTMLHandler extends Handler {
     return 'HTMLHandler'
   }
 
-  static register (fetcher) {
+  static register (fetcher: Fetcher) {
     fetcher.mediatypes['text/html'] = {
       'q': 0.9
     }
   }
 
-  parse (fetcher, responseText, options, response) {
+  parse (
+    fetcher: Fetcher,
+    responseText: string,
+    options: {
+      req: BlankNode,
+      resource: Quad_Subject,
+      original: Quad_Subject,
+    } & Options
+  ): Promise<FetchError> | ExtendedResponse {
     let kb = fetcher.store
 
     // We only handle XHTML so we have to figure out if this is XML
@@ -291,7 +446,7 @@ class HTMLHandler extends Handler {
         "it's XHTML as the content-type was text/html.\n")
 
       let xhtmlHandler = new XHTMLHandler(this.response)
-      return xhtmlHandler.parse(fetcher, responseText, options, response)
+      return xhtmlHandler.parse(fetcher, responseText, options)
     }
 
     // DOCTYPE html
@@ -300,7 +455,7 @@ class HTMLHandler extends Handler {
         'Has XHTML DOCTYPE. Switching to XHTMLHandler.\n')
 
       let xhtmlHandler = new XHTMLHandler(this.response)
-      return xhtmlHandler.parse(fetcher, responseText, options, response)
+      return xhtmlHandler.parse(fetcher, responseText, options)
     }
 
     // xmlns
@@ -309,14 +464,14 @@ class HTMLHandler extends Handler {
         'Has default namespace for XHTML, so switching to XHTMLHandler.\n')
 
       let xhtmlHandler = new XHTMLHandler(this.response)
-      return xhtmlHandler.parse(fetcher, responseText, options, response)
+      return xhtmlHandler.parse(fetcher, responseText, options)
     }
 
     // dc:title
     // no need to escape '/' here
     let titleMatch = (new RegExp('<title>([\\s\\S]+?)</title>', 'im')).exec(responseText)
     if (titleMatch) {
-      kb.add(options.resource, ns.dc('title'), kb.literal(titleMatch[1]),
+      kb.add(options.resource, ns.dc('title'), kb.rdfFactory.literal(titleMatch[1]),
         options.resource) // think about xml:lang later
     }
     kb.add(options.resource, ns.rdf('type'), ns.link('WebPage'), fetcher.appNode)
@@ -332,13 +487,21 @@ class TextHandler extends Handler {
     return 'TextHandler'
   }
 
-  static register (fetcher) {
+  static register (fetcher: Fetcher) {
     fetcher.mediatypes['text/plain'] = {
       'q': 0.5
     }
   }
 
-  parse (fetcher, responseText, options, response) {
+  parse (
+    fetcher: Fetcher,
+    responseText: string,
+    options: {
+      req: Quad_Subject
+      original: Quad_Subject
+      resource: Quad_Subject
+    } & Options
+  ): ExtendedResponse | Promise<FetchError> {
     // We only speak dialects of XML right now. Is this XML?
 
     // Look for an XML declaration
@@ -348,7 +511,7 @@ class TextHandler extends Handler {
         "it's XML but its content-type wasn't XML.\n")
 
       let xmlHandler = new XMLHandler(this.response)
-      return xmlHandler.parse(fetcher, responseText, options, response)
+      return xmlHandler.parse(fetcher, responseText, options)
     }
 
     // Look for an XML declaration
@@ -357,7 +520,7 @@ class TextHandler extends Handler {
         "it's XML but its content-type wasn't XML.\n")
 
       let xmlHandler = new XMLHandler(this.response)
-      return xmlHandler.parse(fetcher, responseText, options, response)
+      return xmlHandler.parse(fetcher, responseText, options)
     }
 
     // We give up finding semantics - this is not an error, just no data
@@ -373,7 +536,7 @@ class N3Handler extends Handler {
     return 'N3Handler'
   }
 
-  static register (fetcher) {
+  static register (fetcher: Fetcher) {
     fetcher.mediatypes['text/n3'] = {
       'q': '1.0'
     } // as per 2008 spec
@@ -387,10 +550,18 @@ class N3Handler extends Handler {
     } // post 2008
   }
 
-  parse (fetcher, responseText, options, response) {
+  parse (
+    fetcher: Fetcher,
+    responseText: string,
+    options: {
+      original: NamedNode
+      req: Quad_Subject
+    } & Options,
+    response: ExtendedResponse
+  ): ExtendedResponse | Promise<FetchError> {
     // Parse the text of this N3 file
     let kb = fetcher.store
-    let p = N3Parser(kb, kb, options.original.uri, options.original.uri,
+    let p = N3Parser(kb, kb, options.original.value, options.original.value,
       null, null, '', null)
     //                p.loadBuf(xhr.responseText)
     try {
@@ -409,7 +580,7 @@ class N3Handler extends Handler {
 }
 N3Handler.pattern = new RegExp('(application|text)/(x-)?(rdf\\+)?(n3|turtle)')
 
-const HANDLERS = {
+const defaultHandlers = {
   RDFXMLHandler, XHTMLHandler, XMLHandler, HTMLHandler, TextHandler, N3Handler
 }
 
@@ -422,12 +593,78 @@ function isXHTML (responseText) {
   return responseText.substr(docTypeStart, docTypeEnd - docTypeStart).indexOf('XHTML') !== -1
 }
 
-function isXML (responseText) {
-  return responseText.match(/\s*<\?xml\s+version\s*=[^<>]+\?>/)
+function isXML (responseText: string): boolean {
+  const match = responseText.match(/\s*<\?xml\s+version\s*=[^<>]+\?>/)
+  return !!match
+}
+
+function isXMLNS (responseText: string): boolean {
+  const match = responseText.match(/[^(<html)]*<html\s+[^<]*xmlns=['"]http:\/\/www.w3.org\/1999\/xhtml["'][^<]*>/)
+  return !!match
+}
+
+type StatusValues =
+  /** No record of web access or record reset */
+  undefined |
+  /** Has been requested, fetch in progress */
+  true |
+  /** Received, OK */
+  'done' |
+  /** Not logged in */
+  401 |
+  /** HTTP status unauthorized */
+  403 |
+  /** Not found, resource does not exist */
+  404 |
+  /** In attempt to counter CORS problems retried */
+  'redirected' |
+  /** If it did fail */
+  'failed' |
+  'parse_error' |
+  /**
+   * URI is not a protocol Fetcher can deal with
+   * other strings mean various other errors.
+   */
+  'unsupported_protocol' |
+  'timeout' |
+  /** Any other HTTP status code */
+  number
+
+interface MediatypesMap {
+  [id: string]: {
+    // Either string '1.0' or number 1.0 is allowed
+    'q'?: number | string
+  };
+}
+
+interface RequestedMap {
+  [uri: string]: StatusValues
+}
+
+interface TimeOutsMap {
+  [uri: string]: number[]
+}
+
+interface FetchQueue {
+  [uri: string]: Promise<ExtendedResponse>
+}
+
+interface FetchCallbacks {
+  [uri: string]: UserCallback[]
 }
 
-function isXMLNS (responseText) {
-  return responseText.match(/[^(<html)]*<html\s+[^<]*xmlns=['"]http:\/\/www.w3.org\/1999\/xhtml["'][^<]*>/)
+interface BooleanMap {
+  [uri: string]: boolean
+}
+
+// Not sure about the shapes of this. Response? FetchError?
+type Result = Response
+
+/** Differs from normal Fetch, has an extended Response type */
+type Fetch = (input: RequestInfo, init?: RequestInit) => Promise<ExtendedResponse>;
+
+interface CallbackifyInterface {
+  fireCallbacks: Function
 }
 
 /** Fetcher
@@ -438,11 +675,50 @@ function isXMLNS (responseText) {
   * figuring how to parse them.  It will also refresh, remove, the data
   * and put back the fata to the web.
  */
-export default class Fetcher {
+export default class Fetcher implements CallbackifyInterface {
+  store: IndexedFormula
+  timeout: number
+  _fetch: Fetch
+  mediatypes: MediatypesMap
+  /** Denoting this session */
+  appNode: BlankNode
   /**
-  * @constructor
-  */
-  constructor (store, options = {}) {
+   * this.requested[uri] states:
+   * undefined     no record of web access or records reset
+   * true          has been requested, fetch in progress
+   * 'done'        received, Ok
+   * 401           Not logged in
+   * 403           HTTP status unauthorized
+   * 404           Resource does not exist. Can be created etc.
+   * 'redirected'  In attempt to counter CORS problems retried.
+   * 'parse_error' Parse error
+   * 'unsupported_protocol'  URI is not a protocol Fetcher can deal with
+   * other strings mean various other errors.
+   */
+  requested: RequestedMap
+  /** List of timeouts associated with a requested URL */
+  timeouts: TimeOutsMap
+  /** Redirected from *key uri* to *value uri* */
+  redirectedTo: Record<string, string>
+  fetchQueue: FetchQueue
+  /** fetchCallbacks[uri].push(callback) */
+  fetchCallbacks: FetchCallbacks
+  /** Keep track of explicit 404s -> we can overwrite etc */
+  nonexistent: BooleanMap
+  lookedUp: BooleanMap
+  handlers: Array<typeof Handler>
+  ns: { [k: string]: (ln: string) => Quad_Predicate }
+  static HANDLERS: {
+    [handlerName: number]: Handler
+  }
+  static CONTENT_TYPE_BY_EXT: Record<string, string>
+  // TODO: Document this
+  static crossSiteProxyTemplate: any
+
+  /** Methods added by calling Util.callbackify in the constructor*/
+  fireCallbacks!: Function
+
+  constructor (store: IndexedFormula, options: Options = {}) {
     this.store = store || new IndexedFormula()
     this.ns = getNS(this.store.rdfFactory)
     this.timeout = options.timeout || 30000
@@ -453,27 +729,14 @@ export default class Fetcher {
       throw new Error('No _fetch function availble for Fetcher')
     }
 
-    this.appNode = this.store.bnode() // Denoting this session
+    this.appNode = this.store.rdfFactory.blankNode()
     this.store.fetcher = this // Bi-linked
     this.requested = {}
-    // this.requested[uri] states:
-    //   undefined     no record of web access or records reset
-    //   true          has been requested, fetch in progress
-    //   'done'        received, Ok
-    //   401           Not logged in
-    //   403           HTTP status unauthorized
-    //   404           Resource does not exist. Can be created etc.
-    //   'redirected'  In attempt to counter CORS problems retried.
-    //   'parse_error' Parse error
-    //   'unsupported_protocol'  URI is not a protocol Fetcher can deal with
-    //   other strings mean various other errors.
-    //
-    this.timeouts = {} // list of timeouts associated with a requested URL
-    this.redirectedTo = {} // When 'redirected'
+    this.timeouts = {}
+    this.redirectedTo = {}
     this.fetchQueue = {}
-    this.fetchCallbacks = {} // fetchCallbacks[uri].push(callback)
-
-    this.nonexistent = {} // keep track of explicit 404s -> we can overwrite etc
+    this.fetchCallbacks = {}
+    this.nonexistent = {}
     this.lookedUp = {}
     this.handlers = []
     this.mediatypes = {
@@ -486,10 +749,10 @@ export default class Fetcher {
     // In switching to fetch(), 'recv', 'headers' and 'load' do not make sense
     Util.callbackify(this, ['request', 'fail', 'refresh', 'retract', 'done'])
 
-    Object.keys(HANDLERS).map(key => this.addHandler(HANDLERS[key]))
+    Object.keys(options.handlers || defaultHandlers).map(key => this.addHandler(defaultHandlers[key]))
   }
 
-  static crossSiteProxy (uri) {
+  static crossSiteProxy (uri: string): undefined | any {
     if (Fetcher.crossSiteProxyTemplate) {
       return Fetcher.crossSiteProxyTemplate
         .replace('{uri}', encodeURIComponent(uri))
@@ -498,12 +761,7 @@ export default class Fetcher {
     }
   }
 
-  /**
-   * @param uri {string}
-   *
-   * @returns {string}
-   */
-  static offlineOverride (uri) {
+  static offlineOverride (uri: string): string {
     // Map the URI to a localhost proxy if we are running on localhost
     // This is used for working offline, e.g. on planes.
     // Is the script itself is running in localhost, then access all
@@ -529,9 +787,14 @@ export default class Fetcher {
     return requestedURI
   }
 
-  static proxyIfNecessary (uri) {
+  static proxyIfNecessary (uri: string) {
     var UI
-    if (typeof window !== 'undefined' && window.panes && (UI = window.panes.UI) && UI.isExtension) {
+    if (
+      typeof window !== 'undefined' &&
+      (window as any).panes &&
+      (UI = (window as any).panes.UI) &&
+      UI.isExtension
+    ) {
       return uri
     } // Extension does not need proxy
 
@@ -577,24 +840,19 @@ export default class Fetcher {
 
   /**
    * Tests whether the uri's protocol is supported by the Fetcher.
-   *
-   * @param uri {string}
-   *
-   * @returns {boolean}
+   * @param uri
    */
-  static unsupportedProtocol (uri) {
+  static unsupportedProtocol (uri: string): boolean {
     let pcol = Uri.protocol(uri)
 
     return (pcol === 'tel' || pcol === 'mailto' || pcol === 'urn')
   }
 
   /** Decide on credentials using old XXHR api or new fetch()  one
-   * @param requestedURI {string}
-   * @param options {Object}
-   *
-   * @returns {}
+   * @param requestedURI
+   * @param options
    */
-  static setCredentials (requestedURI, options = {}) {
+  static setCredentials (requestedURI: string, options: Options = {}) {
     // 2014 CORS problem:
     // XMLHttpRequest cannot load http://www.w3.org/People/Berners-Lee/card.
     // A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin'
@@ -618,17 +876,17 @@ export default class Fetcher {
    * Loads a web resource or resources into the store.
    *
    * A resource may be given as NamedNode object, or as a plain URI.
-   * an arrsy of resources will be given, in which they will be fetched in parallel.
+   * an array of resources will be given, in which they will be fetched in parallel.
    * By default, the HTTP headers are recorded also, in the same store, in a separate graph.
    * This allows code like editable() for example to test things about the resource.
    *
-   * @param uri {Array<NamedNode>|Array<string>|NamedNode|string}
+   * @param uri {Array<RDFlibNamedNode>|Array<string>|RDFlibNamedNode|string}
    *
    * @param [options={}] {Object}
    *
    * @param [options.fetch] {Function}
    *
-   * @param [options.referringTerm] {NamedNode} Referring term, the resource which
+   * @param [options.referringTerm] {RDFlibNamedNode} Referring term, the resource which
    *   referred to this (for tracking bad links)
    *
    * @param [options.contentType] {string} Provided content type (for writes)
@@ -657,29 +915,33 @@ export default class Fetcher {
    *
    * @returns {Promise<Result>}
    */
-  load (uri, options = {}) {
+  load (
+    uri: NamedNode | string | Array<string | NamedNode>,
+    options: Options = {}
+  ): Promise<Result> | Promise<Result>[] {
     options = Object.assign({}, options) // Take a copy as we add stuff to the options!!
     if (uri instanceof Array) {
       return Promise.all(
+        // @ts-ignore Returns an array of promises. Without this ignore, the type is recursive
         uri.map(x => { return this.load(x, Object.assign({}, options)) })
       )
     }
 
-    let docuri = uri.uri || uri
+    let docuri = termValue(uri as RDFlibNamedNode)
     docuri = docuri.split('#')[0]
 
     options = this.initFetchOptions(docuri, options)
 
-    return this.pendingFetchPromise(docuri, options.baseURI, options)
+    const initialisedOptions = this.initFetchOptions(docuri, options)
+
+    return this.pendingFetchPromise(docuri, initialisedOptions.baseURI, initialisedOptions)
   }
 
-  /**
-   * @param uri {string}
-   * @param originalUri {string}
-   * @param options {Object}
-   * @returns {Promise<Result>}
-   */
-  pendingFetchPromise (uri, originalUri, options) {
+  pendingFetchPromise (
+    uri: string,
+    originalUri: string,
+    options: AutoInitOptions
+  ): Promise<Result> {
     let pendingPromise
 
     // Check to see if some request is already dealing with this uri
@@ -694,7 +956,7 @@ export default class Fetcher {
       this.fetchQueue[originalUri] = pendingPromise
 
       // Clean up the queued promise after a time, if it's resolved
-      this.cleanupFetchRequest(originalUri, options, this.timeout)
+      this.cleanupFetchRequest(originalUri, null, this.timeout)
     }
 
     return pendingPromise.then(x => {
@@ -706,21 +968,28 @@ export default class Fetcher {
     })
   }
 
-  cleanupFetchRequest (originalUri, options, timeout) {
+  /**
+   * @param _options - DEPRECATED
+   */
+  cleanupFetchRequest (
+    originalUri: string,
+    _options,
+    timeout: number
+  ) {
+    if (_options !== undefined) {
+      console.warn("_options is deprecated")
+    }
     this.timeouts[originalUri] = (this.timeouts[originalUri] || []).concat(setTimeout(() => {
       if (!this.isPending(originalUri)) {
         delete this.fetchQueue[originalUri]
       }
-    }, timeout))
+    }, timeout) as unknown as number)
   }
 
-  /**
-   * @param uri {string}
-   * @param options {Object}
-   *
-   * @returns {Object}
-   */
-  initFetchOptions (uri, options) {
+  initFetchOptions (
+    uri: string,
+    options: Options
+  ): AutoInitOptions {
     let kb = this.store
 
     let isGet = !options.method || options.method.toUpperCase() === 'GET'
@@ -728,11 +997,11 @@ export default class Fetcher {
       options.force = true
     }
 
-    options.resource = kb.sym(uri) // This might be proxified
+    options.resource = kb.rdfFactory.namedNode(uri) // This might be proxified
     options.baseURI = options.baseURI || uri // Preserve though proxying etc
-    options.original = kb.sym(options.baseURI)
+    options.original = kb.rdfFactory.namedNode(options.baseURI)
     options.req = kb.bnode()
-    options.headers = options.headers || {}
+    options.headers = options.headers || new Headers
 
     if (options.contentType) {
       options.headers['content-type'] = options.contentType
@@ -756,7 +1025,7 @@ export default class Fetcher {
     }
     options.actualProxyURI = actualProxyURI
 
-    return options
+    return options as AutoInitOptions
   }
 
   /**
@@ -767,7 +1036,7 @@ export default class Fetcher {
    *
    * @returns {Promise<Object>} fetch() result or an { error, status } object
    */
-  fetchUri (docuri, options) {
+  fetchUri (docuri: string, options: AutoInitOptions): Promise<ExtendedResponse | FetchError> {
     if (!docuri) {
       return Promise.reject(new Error('Cannot fetch an empty uri'))
     }
@@ -781,17 +1050,24 @@ export default class Fetcher {
     if (!options.force) {
       if (state === 'fetched') {  // URI already fetched and added to store
         return Promise.resolve(
-          this.doneFetch(options, {status: 200, ok: true, statusText: 'Already loaded into quadstore.'})
+          // @ts-ignore This is not a valid response object
+          this.doneFetch(options, {
+            status: 200,
+            ok: true,
+            statusText: 'Already loaded into quadstore.'
+          })
         )
       }
       if (state === 'failed' && this.requested[docuri] === 404) { // Remember nonexistence
         let message = 'Previously failed: ' + this.requested[docuri]
-        let dummyResponse = {
+        // @ts-ignore This is not a valid response object
+        let dummyResponse: ExtendedResponse = {
           url: docuri,
-          status: this.requested[docuri],
+          // This does not comply to Fetch spec, it can be a string value in rdflib
+          status: this.requested[docuri] as number,
           statusText: message,
           responseText: message,
-          headers: {},  // Headers() ???
+          headers: new Headers,  // Headers() ???
           ok: false,
           body: null,
           bodyUsed: false,
@@ -816,31 +1092,32 @@ export default class Fetcher {
 
     let { actualProxyURI } = options
 
-    return this._fetch(actualProxyURI, options)
+    return this._fetch((actualProxyURI as string), options)
       .then(response => this.handleResponse(response, docuri, options),
-            error => { // @@ handleError?
-              let dummyResponse = {
-                url: actualProxyURI,
-                status: 999, // @@ what number/string should fetch failures report?
-                statusText: (error.name || 'network failure') + ': ' +
-                  (error.errno || error.code || error.type),
-                responseText: error.message,
-                headers: {},  // Headers() ???
-                ok: false,
-                body: null,
-                bodyUsed: false,
-                size: 0,
-                timeout: 0
-              }
-              console.log('Fetcher: <' + actualProxyURI + '> Non-HTTP fetch exception: ' + error)
-              return this.handleError(dummyResponse, docuri, options) // possible credentials retry
-              // return this.failFetch(options, 'fetch failed: ' + error, 999, dummyResponse) // Fake status code: fetch exception
-
-              // handleError expects a response so we fake some important bits.
-              /*
-              this.handleError(, docuri, options)
-              */
-            }
+      error => { // @@ handleError?
+        // @ts-ignore Invalid response object
+        let dummyResponse: ExtendedResponse = {
+          url: actualProxyURI as string,
+          status: 999, // @@ what number/string should fetch failures report?
+          statusText: (error.name || 'network failure') + ': ' +
+            (error.errno || error.code || error.type),
+          responseText: error.message,
+          headers: new Headers(),  // Headers() ???
+          ok: false,
+          body: null,
+          bodyUsed: false,
+          size: 0,
+          timeout: 0
+        }
+        console.log('Fetcher: <' + actualProxyURI + '> Non-HTTP fetch exception: ' + error)
+        return this.handleError(dummyResponse, docuri, options) // possible credentials retry
+        // return this.failFetch(options, 'fetch failed: ' + error, 999, dummyResponse) // Fake status code: fetch exception
+
+        // handleError expects a response so we fake some important bits.
+        /*
+        this.handleError(, docuri, options)
+        */
+      }
     )
   }
 
@@ -871,8 +1148,13 @@ export default class Fetcher {
    *    response         The fetch Response object (was: XHR) if there was was one
    *                     includes response.status as the HTTP status if any.
    */
-  nowOrWhenFetched (uri, p2, userCallback, options = {}) {
-    uri = uri.uri || uri // allow symbol object or string to be passed
+  nowOrWhenFetched (
+    uriIn: string | NamedNode,
+    p2?: UserCallback | Options,
+    userCallback?: UserCallback,
+    options: Options = {}
+  ): void {
+    const uri = termValue(uriIn)
 
     if (typeof p2 === 'function') {
       // nowOrWhenFetched (uri, userCallback)
@@ -887,11 +1169,11 @@ export default class Fetcher {
       options = p2
     }
 
-    this.load(uri, options)
-      .then(fetchResponse => {
+    (this.load(uri, options) as Promise<Response>)
+      .then((fetchResponse: ExtendedResponse) => {
         if (userCallback) {
           if (fetchResponse) {
-            if (fetchResponse.ok) {
+            if ((fetchResponse as Response).ok) {
               userCallback(true, 'OK', fetchResponse)
             } else {
               // console.log('@@@ fetcher.js Should not take this path !!!!!!!!!!!!')
@@ -908,14 +1190,14 @@ export default class Fetcher {
             userCallback(false, oops)
           }
         }
-      }, function (err) {
+      }, function (err: FetchError) {
         var message = err.message || err.statusText
         message = 'Failed to load  <' + uri + '> ' + message
         console.log(message)
         if (err.response && err.response.status) {
           message += ' status: ' + err.response.status
         }
-        userCallback(false, message, err.response)
+        (userCallback as any)(false, message, err.response)
       })
   }
 
@@ -923,10 +1205,8 @@ export default class Fetcher {
    * Records a status message (as a literal node) by appending it to the
    * request's metadata status collection.
    *
-   * @param req {BlankNode}
-   * @param statusMessage {string}
    */
-  addStatus (req, statusMessage) {
+  addStatus (req: BlankNode, statusMessage: string) {
     // <Debug about="parsePerformance">
     let now = new Date()
     statusMessage = '[' + now.getHours() + ':' + now.getMinutes() + ':' +
@@ -934,9 +1214,9 @@ export default class Fetcher {
     // </Debug>
     let kb = this.store
 
-    let statusNode = kb.the(req, this.ns.link('status'))
-    if (statusNode && statusNode.append) {
-      statusNode.append(kb.literal(statusMessage))
+    const statusNode = kb.the(req, this.ns.link('status'))
+    if (isCollection(statusNode)) {
+      statusNode.append(kb.rdfFactory.literal(statusMessage))
     } else {
       log.warn('web.js: No list to add to: ' + statusNode + ',' + statusMessage)
     }
@@ -949,35 +1229,40 @@ export default class Fetcher {
    *  - Adds an error triple with the fail message to the metadata
    *  - Fires the 'fail' callback
    *  - Rejects with an error result object, which has a response object if any
-   *
-   * @param options {Object}
-   * @param errorMessage {string}
-   * @param statusCode {number}
-   * @param response {Response}  // when an fetch() error
-   *
-   * @returns {Promise<Object>}
    */
-  failFetch (options, errorMessage, statusCode, response) {
+  failFetch (
+    options: {
+      req: BlankNode
+      original: Quad_Subject
+    } & Options,
+    errorMessage: string,
+    statusCode: StatusValues,
+    response?: ExtendedResponse
+  ): Promise<FetchError> {
     this.addStatus(options.req, errorMessage)
 
     if (!options.noMeta) {
-      this.store.add(options.original, this.ns.link('error'), errorMessage)
+      this.store.add(
+        options.original,
+        this.ns.link('error'),
+        this.store.rdfFactory.literal(errorMessage)
+      )
     }
 
     let meth = (options.method || 'GET').toUpperCase()
     let isGet = meth === 'GET' || meth === 'HEAD'
 
     if (isGet) {  // only cache the status code on GET or HEAD
-      if (!options.resource.equals(options.original)) {
+      if (!(options as any).resource.equals(options.original)) {
         // console.log('@@ Recording failure  ' + meth + '  original ' + options.original +option '( as ' + options.resource + ') : ' + statusCode)
       } else {
         // console.log('@@ Recording ' + meth + ' failure for ' + options.original + ': ' + statusCode)
       }
-      this.requested[Uri.docpart(options.original.uri)] = statusCode
-      this.fireCallbacks('fail', [options.original.uri, errorMessage])
+      this.requested[Uri.docpart(options.original.value)] = statusCode
+      this.fireCallbacks('fail', [options.original.value, errorMessage])
     }
 
-    var err = new Error('Fetcher: ' + errorMessage)
+    var err: FetchError = new Error('Fetcher: ' + errorMessage)
 
     // err.ok = false // Is taken as a response, will work too @@ phase out?
     err.status = statusCode
@@ -989,24 +1274,30 @@ export default class Fetcher {
 
   // in the why part of the quad distinguish between HTML and HTTP header
   // Reverse is set iif the link was rev= as opposed to rel=
-  linkData (originalUri, rel, uri, why, reverse) {
+  linkData (
+    originalUri: NamedNode,
+    rel: string,
+    uri: string,
+    why: Quad_Graph,
+    reverse?: boolean
+  ) {
     if (!uri) return
     let kb = this.store
     let predicate
     // See http://www.w3.org/TR/powder-dr/#httplink for describedby 2008-12-10
-    let obj = kb.sym(Uri.join(uri, originalUri.uri))
+    let obj = kb.rdfFactory.namedNode(Uri.join(uri, originalUri.value))
 
     if (rel === 'alternate' || rel === 'seeAlso' || rel === 'meta' ||
         rel === 'describedby') {
-      if (obj.uri === originalUri.uri) { return }
+      if (obj.value === originalUri.value) { return }
       predicate = this.ns.rdfs('seeAlso')
     } else if (rel === 'type') {
-      predicate = kb.sym('http://www.w3.org/1999/02/22-rdf-syntax-ns#type')
+      predicate = kb.rdfFactory.namedNode('http://www.w3.org/1999/02/22-rdf-syntax-ns#type')
     } else {
       // See https://www.iana.org/assignments/link-relations/link-relations.xml
       // Alas not yet in RDF yet for each predicate
       // encode space in e.g. rel="shortcut icon"
-      predicate = kb.sym(
+      predicate = kb.rdfFactory.namedNode(
         Uri.join(encodeURIComponent(rel),
           'http://www.iana.org/assignments/link-relations/')
       )
@@ -1018,7 +1309,11 @@ export default class Fetcher {
     }
   }
 
-  parseLinkHeader (linkHeader, originalUri, reqNode) {
+  parseLinkHeader (
+    linkHeader: string,
+    originalUri: NamedNode,
+    reqNode: Quad_Graph
+  ): void {
     if (!linkHeader) { return }
 
     // const linkexp = /<[^>]*>\s*(\s*;\s*[^()<>@,;:"/[\]?={} \t]+=(([^()<>@,;:"/[]?={} \t]+)|("[^"]*")))*(,|$)/g
@@ -1033,11 +1328,14 @@ export default class Fetcher {
 
     const matches = linkHeader.match(linkexp)
 
+    if (matches == null) return;
+
     for (let i = 0; i < matches.length; i++) {
       let split = matches[i].split('>')
       let href = split[0].substring(1)
       let ps = split[1]
       let s = ps.match(paramexp)
+      if (s == null) return
       for (let j = 0; j < s.length; j++) {
         let p = s[j]
         let paramsplit = p.split('=')
@@ -1048,11 +1346,17 @@ export default class Fetcher {
     }
   }
 
-  doneFetch (options, response) {
+  doneFetch (
+    options: {
+      req: Quad_Subject,
+      original: Quad_Subject
+    } & Options,
+    response: ExtendedResponse
+  ): Response {
     this.addStatus(options.req, 'Done.')
-    this.requested[options.original.uri] = 'done'
+    this.requested[options.original.value] = 'done'
 
-    this.fireCallbacks('done', [options.original.uri])
+    this.fireCallbacks('done', [options.original.value])
 
     response.req = options.req  // Set the request meta blank node
 
@@ -1064,14 +1368,14 @@ export default class Fetcher {
    * If only one was flagged as looked up, then the new node is looked up again,
    * which will make sure all the URIs are dereferenced
    */
-  nowKnownAs (was, now) {
-    if (this.lookedUp[was.uri]) {
+  nowKnownAs (was: Quad_Subject, now: Quad_Subject): void {
+    if (this.lookedUp[was.value]) {
       // Transfer userCallback
-      if (!this.lookedUp[now.uri]) {
+      if (!this.lookedUp[now.value]) {
         this.lookUpThing(now, was)
       }
-    } else if (this.lookedUp[now.uri]) {
-      if (!this.lookedUp[was.uri]) {
+    } else if (this.lookedUp[now.value]) {
+      if (!this.lookedUp[was.value]) {
         this.lookUpThing(was, now)
       }
     }
@@ -1079,21 +1383,19 @@ export default class Fetcher {
 
   /**
    * Writes back to the web what we have in the store for this uri
-   *
-   * @param uri {Node|string}
-   * @param [options={}]
-   *
-   * @returns {Promise}
    */
-  putBack (uri, options = {}) {
-    uri = uri.uri || uri // Accept object or string
-    let doc = new NamedNode(uri).doc() // strip off #
-    options.contentType = options.contentType || 'text/turtle'
-    options.data = serialize(doc, this.store, doc.uri, options.contentType)
-    return this.webOperation('PUT', uri, options)
-  }
-
-  webCopy (here, there, contentType) {
+  putBack (
+    uri: NamedNode | string,
+    options: Options = {}
+  ): Promise<Response> {
+    const uriSting = termValue(uri)
+    let doc = new RDFlibNamedNode(uriSting).doc() // strip off #
+    options.contentType = options.contentType || TurtleContentType
+    options.data = serialize(doc, this.store, doc.value, options.contentType) as string
+    return this.webOperation('PUT', uriSting, options)
+  }
+
+  webCopy (here: string, there: string, contentType): Promise<ExtendedResponse> {
     return this.webOperation('GET', here)
       .then((result) => {
         return this.webOperation(
@@ -1102,18 +1404,12 @@ export default class Fetcher {
       })
   }
 
-  /**
-   * @param uri {string}
-   * @param [options] {Object}
-   *
-   * @returns {Promise<Response>}
-   */
-  delete (uri, options) {
+  delete (uri: string, options: Options): Promise<ExtendedResponse> {
     return this.webOperation('DELETE', uri, options)
       .then(response => {
         this.requested[uri] = 404
         this.nonexistent[uri] = true
-        this.unload(this.store.sym(uri))
+        this.unload(this.store.rdfFactory.namedNode(uri))
 
         return response
       })
@@ -1122,23 +1418,26 @@ export default class Fetcher {
   /** Create an empty resource if it really does not exist
    *  Be absolutely sure something does not exist before creating a new empty file
    * as otherwise existing could  be deleted.
-   * @param doc {NamedNode} - The resource
-   * @returns {Promise}
+   * @param doc - The resource
   */
-  async createIfNotExists (doc, contentType = 'text/turtle', data = '') {
+  async createIfNotExists (
+    doc: RDFlibNamedNode,
+    contentType = TurtleContentType,
+    data = ''
+  ): Promise<ExtendedResponse> {
     const fetcher = this
     try {
-      var response = await fetcher.load(doc)
+      var response = await fetcher.load(doc as NamedNode)
     } catch (err) {
       if (err.response.status === 404) {
         console.log('createIfNotExists: doc does NOT exist, will create... ' + doc)
         try {
-          response = await fetcher.webOperation('PUT', doc.uri, {data, contentType})
+          response = await fetcher.webOperation('PUT', doc.value, {data, contentType})
         } catch (err) {
           console.log('createIfNotExists doc FAILED: ' + doc + ': ' + err)
           throw err
         }
-        delete fetcher.requested[doc.uri] // delete cached 404 error
+        delete fetcher.requested[doc.value] // delete cached 404 error
         // console.log('createIfNotExists doc created ok ' + doc)
         return response
       } else {
@@ -1147,20 +1446,22 @@ export default class Fetcher {
       }
     }
     // console.log('createIfNotExists: doc exists, all good: ' + doc)
-    return response
+    return response as Response
   }
 
   /**
-   * @param parentURI {string} URI of parent container
-   * @param [folderName] {string} Optional folder name (slug)
-   * @param [data] {string} Optional folder metadata
-   *
-   * @returns {Promise<Response>}
+   * @param parentURI URI of parent container
+   * @param folderName - Optional folder name (slug)
+   * @param data - Optional folder metadata
    */
-  createContainer (parentURI, folderName, data) {
+  createContainer (
+    parentURI: string,
+    folderName: string,
+    data: string
+  ): Promise<Response> {
     let headers = {
       // Force the right mime type for containers
-      'content-type': 'text/turtle',
+      'content-type': TurtleContentType,
       'link': this.ns.ldp('BasicContainer') + '; rel="type"'
     }
 
@@ -1168,7 +1469,8 @@ export default class Fetcher {
       headers['slug'] = folderName
     }
 
-    let options = { headers }
+    // @ts-ignore These headers lack some of the required operators.
+    let options: Options = { headers }
 
     if (data) {
       options.body = data
@@ -1177,13 +1479,13 @@ export default class Fetcher {
     return this.webOperation('POST', parentURI, options)
   }
 
-  invalidateCache (uri) {
-    uri = uri.uri || uri // Allow a NamedNode to be passed as it is very common
+  invalidateCache (iri: string | NamedNode): void {
+    const uri = termValue(iri)
     const fetcher = this
     if (fetcher.fetchQueue && fetcher.fetchQueue[uri]) {
       console.log('Internal error - fetchQueue exists ' + uri)
       var promise = fetcher.fetchQueue[uri]
-      if (promise.PromiseStatus === 'resolved') {
+      if (promise['PromiseStatus'] === 'resolved') {
         delete fetcher.fetchQueue[uri]
       } else { // pending
         delete fetcher.fetchQueue[uri]
@@ -1199,21 +1501,21 @@ export default class Fetcher {
       delete fetcher.nonexistent[uri]
     }
   }
+
   /**
    * A generic web opeation, at the fetch() level.
    * does not invole the quadstore.
    *
    *  Returns promise of Response
    *  If data is returned, copies it to response.responseText before returning
-   *
-   * @param method
-   * @param uri  or NamedNode
-   * @param options
-   *
-   * @returns {Promise<Response>}
    */
-  webOperation (method, uri, options = {}) {
-    uri = uri.uri || uri // Allow a NamedNode to be passed as it is very common
+  webOperation (
+    method: HTTPMethods,
+    uriIn: string | NamedNode,
+    // Not sure about this type. Maybe this Options is different?
+    options: Options = {}
+  ): Promise<ExtendedResponse> {
+    const uri = termValue(uriIn)
     options.method = method
     options.body = options.data || options.body
     options.force = true
@@ -1223,8 +1525,8 @@ export default class Fetcher {
       throw new Error('Web operation sending data must have a defined contentType.')
     }
     if (options.contentType) {
-      options.headers = options.headers || {}
-      options.headers['content-type'] = options.contentType
+      (options as any).headers = options.headers || {};
+      (options as any).headers['content-type'] = options.contentType
     }
     Fetcher.setCredentials(uri, options)
 
@@ -1247,11 +1549,11 @@ export default class Fetcher {
           if (response.statusText) msg += ' (' + response.statusText + ')'
           msg += ' on ' + method + ' of <' + uri + '>'
           if (response.responseText) msg += ': ' + response.responseText
-          let e2 = new Error(msg)
+          let e2: FetchError = new Error(msg)
           e2.response = response
           reject(e2)
         }
-      }, err => {
+      }, (err: Error) => {
         let msg = 'Fetch error for ' + method + ' of <' + uri + '>:' + err
         reject(new Error(msg))
       })
@@ -1262,14 +1564,15 @@ export default class Fetcher {
    * Looks up something.
    * Looks up all the URIs a things has.
    *
-   * @param term {NamedNode} canonical term for the thing whose URI is
+   * @param term - canonical term for the thing whose URI is
    *   to be dereferenced
-   * @param rterm {NamedNode} the resource which referred to this
+   * @param rterm - the resource which referred to this
    *   (for tracking bad links)
-   *
-   * @returns {Promise}
    */
-  lookUpThing (term, rterm) {
+  lookUpThing (
+    term: Quad_Subject,
+    rterm: Quad_Subject
+  ): Promise<Response> | Promise<Response>[] {
     let uris = this.store.uris(term)  // Get all URIs
     uris = uris.map(u => Uri.docpart(u))  // Drop hash fragments
 
@@ -1277,30 +1580,30 @@ export default class Fetcher {
       this.lookedUp[u] = true
     })
 
+    // @ts-ignore Recursive type
     return this.load(uris, { referringTerm: rterm })
   }
 
   /**
    * Looks up response header.
    *
-   * @param doc
-   * @param header
-   *
    * @returns {Array|undefined} a list of header values found in a stored HTTP
    *   response, or [] if response was found but no header found,
    *   or undefined if no response is available.
    * Looks for { [] link:requestedURI ?uri; link:response [ httph:header-name  ?value ] }
    */
-  getHeader (doc, header) {
+  getHeader (
+    doc: NamedNode,
+    header: string
+  ): undefined | string[] {
     const kb = this.store
-    const requests = kb.each(undefined, this.ns.link('requestedURI'), doc.uri)
+    const requests = kb.each(undefined, this.ns.link('requestedURI'), doc) as Quad_Subject[]
 
     for (let r = 0; r < requests.length; r++) {
       let request = requests[r]
       if (request !== undefined) {
-        let response = kb.any(request, this.ns.link('response'))
-
-        if (response !== undefined && kb.anyValue(response, this.ns.http('status')) && kb.anyValue(response, this.ns.http('status')).startsWith('2')) {
+        let response = kb.any(request, this.ns.link('response')) as Quad_Subject
+        if (response !== undefined && kb.anyValue(response, this.ns.http('status')) && (kb.anyValue(response, this.ns.http('status')) as string).startsWith('2')) {
           // Only look at success returns - not 401 error messagess etc
           let results = kb.each(response, this.ns.httph(header.toLowerCase()))
 
@@ -1315,24 +1618,22 @@ export default class Fetcher {
     return undefined
   }
 
-  /**
-   *
-   * @param docuri
-   * @param options
-   */
-  saveRequestMetadata (docuri, options) {
+  saveRequestMetadata (
+    docuri: string,
+    options: AutoInitOptions
+  ) {
     let req = options.req
     let kb = this.store
     let rterm = options.referringTerm
 
     this.addStatus(options.req, 'Accept: ' + options.headers['accept'])
 
-    if (rterm && rterm.uri) {
-      kb.add(docuri, this.ns.link('requestedBy'), rterm.uri, this.appNode)
+    if (isNamedNode(rterm)) {
+      kb.add(kb.rdfFactory.namedNode(docuri), this.ns.link('requestedBy'), rterm, this.appNode)
     }
 
-    if (options.original && options.original.uri !== docuri) {
-      kb.add(req, this.ns.link('orginalURI'), kb.literal(options.original.uri),
+    if (options.original && options.original.value !== docuri) {
+      kb.add(req, this.ns.link('orginalURI'), kb.rdfFactory.literal(options.original.value),
         this.appNode)
     }
 
@@ -1341,35 +1642,41 @@ export default class Fetcher {
       now.getSeconds() + '] '
 
     kb.add(req, this.ns.rdfs('label'),
-      kb.literal(timeNow + ' Request for ' + docuri), this.appNode)
-    kb.add(req, this.ns.link('requestedURI'), kb.literal(docuri), this.appNode)
+      kb.rdfFactory.literal(timeNow + ' Request for ' + docuri), this.appNode)
+    kb.add(req, this.ns.link('requestedURI'), kb.rdfFactory.literal(docuri), this.appNode)
     kb.add(req, this.ns.link('status'), kb.collection(), this.appNode)
   }
 
-  saveResponseMetadata (response, options) {
+  saveResponseMetadata (
+    response: Response,
+    options: {
+      req: BlankNode,
+      resource: Quad_Subject
+    } & Options
+  ): BlankNode {
     const kb = this.store
 
     let responseNode = kb.bnode()
 
     kb.add(options.req, this.ns.link('response'), responseNode, responseNode)
     kb.add(responseNode, this.ns.http('status'),
-      kb.literal(response.status), responseNode)
+    kb.rdfFactory.literal(response.status as any), responseNode)
     kb.add(responseNode, this.ns.http('statusText'),
-      kb.literal(response.statusText), responseNode)
+    kb.rdfFactory.literal(response.statusText), responseNode)
 
-    if (!options.resource.uri.startsWith('http')) {
+    if (!options.resource.value.startsWith('http')) {
       return responseNode
     }
 
     // Save the response headers
     response.headers.forEach((value, header) => {
-      kb.add(responseNode, this.ns.httph(header), value, responseNode)
+      kb.add(responseNode, this.ns.httph(header), this.store.rdfFactory.literal(value), responseNode)
 
       if (header === 'content-type') {
         kb.add(
           options.resource,
           this.ns.rdf('type'),
-          kb.namedNode(Util.mediaTypeClass(value).value),
+          kb.rdfFactory.namedNode(Util.mediaTypeClass(value).value),
           responseNode
         )
       }
@@ -1378,11 +1685,11 @@ export default class Fetcher {
     return responseNode
   }
 
-  objectRefresh (term) {
+  objectRefresh (term: NamedNode): void {
     let uris = this.store.uris(term) // Get all URIs
     if (typeof uris !== 'undefined') {
       for (let i = 0; i < uris.length; i++) {
-        this.refresh(this.store.sym(Uri.docpart(uris[i])))
+        this.refresh(this.store.rdfFactory.namedNode(Uri.docpart(uris[i])))
         // what about rterm?
       }
     }
@@ -1390,10 +1697,13 @@ export default class Fetcher {
 
   /* refresh  Reload data from a given document
   **
-  ** @param  {NamedNode} term -  An RDF Named Node for the eodcument in question
-  ** @param  {function } userCallback - A function userCallback(ok, message, response)
+  ** @param term - An RDF Named Node for the eodcument in question
+  ** @param userCallback - A function userCallback(ok, message, response)
   */
-  refresh (term, userCallback) { // sources_refresh
+  refresh (
+    term: NamedNode,
+    userCallback?: UserCallback
+  ): void { // sources_refresh
     this.fireCallbacks('refresh', arguments)
 
     this.nowOrWhenFetched(term, { force: true, clearPreviousData: true },
@@ -1402,27 +1712,30 @@ export default class Fetcher {
 
  /* refreshIfExpired   Conditional refresh if Expired
  **
- ** @param  {NamedNode} term -  An RDF Named Node for the eodcument in question
- ** @param  {function } userCallback - A function userCallback(ok, message, response)
+ ** @param term - An RDF Named Node for the eodcument in question
+ ** @param userCallback - A function userCallback(ok, message, response)
  */
-  refreshIfExpired (term, userCallback) {
+  refreshIfExpired (
+    term: NamedNode,
+    userCallback: UserCallback
+  ): void {
     let exp = this.getHeader(term, 'Expires')
-    if (!exp || (new Date(exp).getTime()) <= (new Date().getTime())) {
+    if (!exp || (new Date(exp[0]).getTime()) <= (new Date().getTime())) {
       this.refresh(term, userCallback)
     } else {
       userCallback(true, 'Not expired', {})
     }
   }
 
-  retract (term) { // sources_retract
+  retract (term: Quad_Graph) { // sources_retract
     this.store.removeMany(undefined, undefined, undefined, term)
-    if (term.uri) {
-      delete this.requested[Uri.docpart(term.uri)]
+    if (term.value) {
+      delete this.requested[Uri.docpart(term.value)]
     }
     this.fireCallbacks('retract', arguments)
   }
 
-  getState (docuri) {
+  getState (docuri: string) {
     if (typeof this.requested[docuri] === 'undefined') {
       return 'unrequested'
     } else if (this.requested[docuri] === true) {
@@ -1436,24 +1749,27 @@ export default class Fetcher {
     }
   }
 
-  isPending (docuri) { // sources_pending
+  isPending (docuri: string) { // sources_pending
     // doing anyStatementMatching is wasting time
     // if it's not pending: false -> flailed
     //   'done' -> done 'redirected' -> redirected
     return this.requested[docuri] === true
   }
 
-  unload (term) {
+  unload (term: NamedNode) {
     this.store.removeDocument(term)
-    delete this.requested[term.uri] // So it can be loaded again
+    delete this.requested[term.value] // So it can be load2ed again
   }
 
-  addHandler (handler) {
-    this.handlers.push(handler)
-    handler.register(this)
+  addHandler (handler: typeof Handler) {
+    this.handlers.push(handler);
+    (handler as any).register(this)
   }
 
-  retryNoCredentials (docuri, options) {
+  retryNoCredentials (
+    docuri: string,
+    options
+  ): Promise<Result> {
     console.log('Fetcher: CORS: RETRYING with NO CREDENTIALS for ' + options.resource)
 
     options.retriedWithNoCredentials = true // protect against being called twice
@@ -1466,18 +1782,14 @@ export default class Fetcher {
     this.addStatus(options.req,
       'Abort: Will retry with credentials SUPPRESSED to see if that helps')
 
-    return this.load(docuri, newOptions)
+    return this.load(docuri, newOptions) as Promise<Result>
   }
 
   /**
    * Tests whether a request is being made to a cross-site URI (for purposes
    * of retrying with a proxy)
-   *
-   * @param uri {string}
-   *
-   * @returns {boolean}
    */
-  isCrossSite (uri) {
+  isCrossSite (uri: string): boolean {
     // Mashup situation, not node etc
     if (typeof document === 'undefined' || !document.location) {
       return false
@@ -1485,20 +1797,18 @@ export default class Fetcher {
 
     const hostpart = Uri.hostpart
     const here = '' + document.location
-    return hostpart(here) && hostpart(uri) && hostpart(here) !== hostpart(uri)
+    return (hostpart(here) && hostpart(uri) && hostpart(here)) !== hostpart(uri)
   }
 
   /**
    * Called when there's a network error in fetch(), or a response
    * with status of 0.
-   *
-   * @param response {Response|Error}
-   * @param docuri {string}
-   * @param options {Object}
-   *
-   * @returns {Promise}
    */
-  handleError (response, docuri, options) {
+  handleError (
+    response: ExtendedResponse | Error,
+    docuri: string,
+    options: AutoInitOptions
+  ): Promise<ExtendedResponse | FetchError> {
     if (this.isCrossSite(docuri)) {
       // Make sure we haven't retried already
       if (options.credentials && options.credentials === 'include' && !options.retriedWithNoCredentials) {
@@ -1516,7 +1826,7 @@ export default class Fetcher {
     }
 
     var message
-    if (response.message) {
+    if (response instanceof Error) {
       message = 'Fetch error: ' + response.message
     } else {
       message = response.statusText
@@ -1526,43 +1836,50 @@ export default class Fetcher {
     }
 
     // This is either not a CORS error, or retries have been made
-    return this.failFetch(options, message, response.status || 998, response)
+    return this.failFetch(options, message, (response as Response).status || 998, (response as Response))
   }
 
   // deduce some things from the HTTP transaction
-  addType (rdfType, req, kb, locURI) { // add type to all redirected resources too
+  addType (
+    rdfType: NamedNode,
+    req: Quad_Subject,
+    kb: IndexedFormula,
+    locURI: string
+  ): void { // add type to all redirected resources too
     let prev = req
     if (locURI) {
       var reqURI = kb.any(prev, this.ns.link('requestedURI'))
-      if (reqURI && reqURI !== locURI) {
-        kb.add(kb.sym(locURI), this.ns.rdf('type'), rdfType, this.appNode)
+      if (reqURI && reqURI.value !== locURI) {
+        kb.add(kb.rdfFactory.namedNode(locURI), this.ns.rdf('type'), rdfType, this.appNode)
       }
     }
     for (;;) {
       const doc = kb.any(prev, this.ns.link('requestedURI'))
       if (doc && doc.value) {
-        kb.add(kb.sym(doc.value), this.ns.rdf('type'), rdfType, this.appNode)
+        kb.add(kb.rdfFactory.namedNode(doc.value), this.ns.rdf('type'), rdfType, this.appNode)
       } // convert Literal
-      prev = kb.any(undefined, kb.sym('http://www.w3.org/2007/ont/link#redirectedRequest'), prev)
+      prev = kb.any(undefined, kb.rdfFactory.namedNode('http://www.w3.org/2007/ont/link#redirectedRequest'), prev) as Quad_Subject
       if (!prev) { break }
-      var response = kb.any(prev, kb.sym('http://www.w3.org/2007/ont/link#response'))
+      var response = kb.any(prev, kb.rdfFactory.namedNode('http://www.w3.org/2007/ont/link#response'))
       if (!response) { break }
-      var redirection = kb.any(response, kb.sym('http://www.w3.org/2007/ont/http#status'))
+      var redirection = kb.any((response as NamedNode), kb.rdfFactory.namedNode('http://www.w3.org/2007/ont/http#status'))
       if (!redirection) { break }
-      if (redirection !== '301' && redirection !== '302') { break }
+      // @ts-ignore always true?
+      if ((redirection !== '301') && (redirection !== '302')) { break }
     }
   }
 
   /**
    * Handle fetch() response
-   *
-   * @param response {Response} fetch() response object
-   * @param docuri {string}
-   * @param options {Object}
    */
-  handleResponse (response, docuri, options) {
+  handleResponse (
+    response: ExtendedResponse,
+    docuri: string,
+    options: AutoInitOptions
+  ): Promise<FetchError | ExtendedResponse> | ExtendedResponse {
+
     const kb = this.store
-    const headers = response.headers
+    const headers = (response as Response).headers
 
     const reqNode = options.req
 
@@ -1583,7 +1900,7 @@ export default class Fetcher {
 
     if (response.status >= 400) {
       if (response.status === 404) {
-        this.nonexistent[options.original.uri] = true
+        this.nonexistent[options.original.value] = true
         this.nonexistent[docuri] = true
       }
 
@@ -1595,8 +1912,8 @@ export default class Fetcher {
         })
     }
 
-    var diffLocation = null
-    var absContentLocation = null
+    var diffLocation: null | string = null
+    var absContentLocation: null | string = null
     if (contentLocation) {
       absContentLocation = Uri.join(contentLocation, docuri)
       if (absContentLocation !== docuri) {
@@ -1604,9 +1921,9 @@ export default class Fetcher {
       }
     }
     if (response.status === 200) {
-      this.addType(this.ns.link('Document'), reqNode, kb, docuri)
+      this.addType(this.ns.link('Document') as NamedNode, reqNode, kb, docuri)
       if (diffLocation) {
-        this.addType(this.ns.link('Document'), reqNode, kb,
+        this.addType(this.ns.link('Document') as NamedNode, reqNode, kb,
           diffLocation)
       }
 
@@ -1619,10 +1936,10 @@ export default class Fetcher {
         contentType.includes('application/pdf')
 
       if (contentType && isImage) {
-        this.addType(kb.sym('http://purl.org/dc/terms/Image'), reqNode, kb,
+        this.addType(kb.rdfFactory.namedNode('http://purl.org/dc/terms/Image'), reqNode, kb,
           docuri)
         if (diffLocation) {
-          this.addType(kb.sym('http://purl.org/dc/terms/Image'), reqNode, kb,
+          this.addType(kb.rdfFactory.namedNode('http://purl.org/dc/terms/Image'), reqNode, kb,
             diffLocation)
         }
       }
@@ -1630,7 +1947,7 @@ export default class Fetcher {
 
     // If we have already got the thing at this location, abort
     if (contentLocation) {
-      if (!options.force && diffLocation && this.requested[absContentLocation] === 'done') {
+      if (!options.force && diffLocation && this.requested[absContentLocation as string] === 'done') {
         // we have already fetched this
         // should we smush too?
         // log.info("HTTP headers indicate we have already" + " retrieved " +
@@ -1638,12 +1955,12 @@ export default class Fetcher {
         return this.doneFetch(options, response)
       }
 
-      this.requested[absContentLocation] = true
+      this.requested[absContentLocation as string] = true
     }
 
-    this.parseLinkHeader(headers.get('link'), options.original, reqNode)
+    this.parseLinkHeader(headers.get('link') as string, options.original, reqNode)
 
-    let handler = this.handlerForContentType(contentType, response)
+    let handler = this.handlerForContentType(contentType, response) as Handler
 
     if (!handler) {
       //  Not a problem, we just don't extract data
@@ -1651,30 +1968,30 @@ export default class Fetcher {
       return this.doneFetch(options, response)
     }
 
-    return response.text()
+    return response
+      .text()
+      // @ts-ignore Types seem right
       .then(responseText => {
         response.responseText = responseText
-        return handler.parse(this, responseText, options, response)
+        return (handler as N3Handler).parse(this, responseText, options, response)
       })
   }
 
-  saveErrorResponse (response, responseNode) {
+  saveErrorResponse (
+    response: ExtendedResponse,
+    responseNode: Quad_Subject
+  ): Promise<void> {
     let kb = this.store
 
     return response.text()
       .then(content => {
         if (content.length > 10) {
-          kb.add(responseNode, this.ns.http('content'), kb.literal(content), responseNode)
+          kb.add(responseNode, this.ns.http('content'), kb.rdfFactory.literal(content), responseNode)
         }
       })
   }
 
-  /**
-   * @param contentType {string}
-   *
-   * @returns {Handler|null}
-   */
-  handlerForContentType (contentType, response) {
+  handlerForContentType (contentType: string, response: ExtendedResponse): Handler | null {
     if (!contentType) {
       return null
     }
@@ -1683,39 +2000,32 @@ export default class Fetcher {
       return contentType.match(handler.pattern)
     })
 
+    // @ts-ignore in practice all Handlers have constructors.
     return Handler ? new Handler(response) : null
   }
 
-  /**
-   * @param uri {string}
-   *
-   * @returns {string}
-   */
-  guessContentType (uri) {
-    return CONTENT_TYPE_BY_EXT[uri.split('.').pop()]
+  guessContentType (uri: string): ContentType | undefined {
+    return CONTENT_TYPE_BY_EXT[uri.split('.').pop() as string]
   }
 
-  /**
-   * @param options {Object}
-   * @param headers {Headers}
-   *
-   * @returns {string}
-   */
-  normalizedContentType (options, headers) {
+  normalizedContentType (
+    options: AutoInitOptions,
+    headers: Headers
+  ): ContentType | string | null {
     if (options.forceContentType) {
       return options.forceContentType
     }
 
     let contentType = headers.get('content-type')
     if (!contentType || contentType.includes('application/octet-stream')) {
-      let guess = this.guessContentType(options.resource.uri)
+      let guess = this.guessContentType(options.resource.value)
 
       if (guess) {
         return guess
       }
     }
 
-    let protocol = Uri.protocol(options.resource.uri)
+    let protocol = Uri.protocol(options.resource.value) as string
 
     if (!contentType && ['file', 'chrome'].includes(protocol)) {
       return 'text/xml'
@@ -1726,13 +2036,11 @@ export default class Fetcher {
 
   /**
    * Sends a new request to the specified uri. (Extracted from `onerrorFactory()`)
-   *
-   * @param newURI {string}
-   * @param options {Object}
-   *
-   * @returns {Promise<Response>}
    */
-  redirectToProxy (newURI, options) {
+  redirectToProxy (
+    newURI: string,
+    options: AutoInitOptions
+  ): Promise<ExtendedResponse | FetchError> {
     this.addStatus(options.req, 'BLOCKED -> Cross-site Proxy to <' + newURI + '>')
 
     options.proxyUsed = true
@@ -1741,15 +2049,15 @@ export default class Fetcher {
     const oldReq = options.req  // request metadata blank node
 
     if (!options.noMeta) {
-      kb.add(oldReq, this.ns.link('redirectedTo'), kb.sym(newURI), oldReq)
+      kb.add(oldReq, this.ns.link('redirectedTo'), kb.rdfFactory.namedNode(newURI), oldReq)
       this.addStatus(oldReq, 'redirected to new request') // why
     }
 
-    this.requested[options.resource.uri] = 'redirected'
-    this.redirectedTo[options.resource.uri] = newURI
+    this.requested[options.resource.value] = 'redirected'
+    this.redirectedTo[options.resource.value] = newURI
 
     let newOptions = Object.assign({}, options)
-    newOptions.baseURI = options.resource.uri
+    newOptions.baseURI = options.resource.value
 
     return this.fetchUri(newURI, newOptions)
       .then(response => {
@@ -1761,7 +2069,13 @@ export default class Fetcher {
       })
   }
 
-  setRequestTimeout (uri, options) {
+  setRequestTimeout (
+    uri: string,
+    options: {
+      req: Quad_Subject
+      original: Quad_Subject
+    } & Options
+  ): Promise<number | FetchError> {
     return new Promise((resolve) => {
       this.timeouts[uri] = (this.timeouts[uri] || []).concat(setTimeout(() => {
         if (this.isPending(uri) &&
@@ -1769,11 +2083,14 @@ export default class Fetcher {
             !options.proxyUsed) {
           resolve(this.failFetch(options, `Request to ${uri} timed out`, 'timeout'))
         }
-      }, this.timeout))
+      }, this.timeout) as unknown as number)
     })
   }
 
-  addFetchCallback (uri, callback) {
+  addFetchCallback (
+    uri: string,
+    callback: UserCallback
+  ): void {
     if (!this.fetchCallbacks[uri]) {
       this.fetchCallbacks[uri] = [callback]
     } else {
@@ -1803,5 +2120,5 @@ export default class Fetcher {
 // whether we want to track it ot not. including ontologies loaed though the XSSproxy
 }
 
-Fetcher.HANDLERS = HANDLERS
+Fetcher.HANDLERS = defaultHandlers
 Fetcher.CONTENT_TYPE_BY_EXT = CONTENT_TYPE_BY_EXT
diff --git a/src/formula.js b/src/formula.js
deleted file mode 100644
index 34a361155..000000000
--- a/src/formula.js
+++ /dev/null
@@ -1,679 +0,0 @@
-'use strict'
-import BlankNode from './blank-node'
-import ClassOrder from './class-order'
-import Collection from './collection'
-import CanonicalDataFactory from './data-factory-internal'
-import log from './log'
-import NamedNode from './named-node'
-import Namespace from './namespace'
-import Node from './node'
-import Serializer from './serialize'
-import Statement from './statement'
-import { appliedFactoryMethods, arrayToStatements, isStatement } from './util'
-import Variable from './variable'
-
-/** @module formula */
-
-export default class Formula extends Node {
-  /**
-  * @constructor
-  * @param statements - Initial array of statements
-  * @param constraints - initial array of constraints
-  * @param initBindings - initial bindings used in Query
-  * @param optional - optional
-  * @param opts
-  * @param {DataFactory} opts.rdfFactory - The rdf factory that should be used by the store
-  */
-  constructor (statements, constraints, initBindings, optional, opts = {}) {
-    super()
-    this.termType = Formula.termType
-    this.statements = statements || []
-    this.constraints = constraints || []
-    this.initBindings = initBindings || []
-    this.optional = optional || []
-
-    this.rdfFactory = (opts && opts.rdfFactory) || CanonicalDataFactory
-    // Enable default factory methods on this while preserving factory context.
-    for(const factoryMethod of appliedFactoryMethods) {
-      this[factoryMethod] = (...args) => this.rdfFactory[factoryMethod](...args)
-    }
-  }
-  /** Add a statement from its parts
-  * @param {Node} subject - the first part of the statemnt
-  * @param {Node} predicate - the second part of the statemnt
-  * @param {Node} obbject - the third part of the statemnt
-  * @param {Node} graph - the last part of the statemnt
-  */
-  add (subject, predicate, object, graph) {
-    return this.statements.push(this.rdfFactory.quad(subject, predicate, object, graph))
-  }
-  /** Add a statment object
-  * @param {Statement} statement - an existing constructed statement to add
-  */
-  addStatement (st) {
-    return this.statements.push(st)
-  }
-  bnode (id) {
-    return this.rdfFactory.blankNode(id)
-  }
-
-  addAll (statements) {
-    statements.forEach(quad => {
-      this.add(quad.subject, quad.predicate, quad.object, quad.graph)
-    })
-  }
-
-  /** Follow link from one node, using one wildcard, looking for one
-  *
-  * For example, any(me, knows, null, profile)  - a person I know accoring to my profile .
-  * any(me, knows, null, null)  - a person I know accoring to anything in store .
-  * any(null, knows, me, null)  - a person who know me accoring to anything in store .
-  *
-  * @param {Node} subject - A node to search for as subject, or if null, a wildcard
-  * @param {Node} predicate - A node to search for as predicate, or if null, a wildcard
-  * @param {Node} object - A node to search for as object, or if null, a wildcard
-  * @param {Node} graph - A node to search for as graph, or if null, a wildcard
-  * @returns {Node} - A node which match the wildcard position, or null
-  */
-  any (s, p, o, g) {
-    var st = this.anyStatementMatching(s, p, o, g)
-    if (st == null) {
-      return void 0
-    } else if (s == null) {
-      return st.subject
-    } else if (p == null) {
-      return st.predicate
-    } else if (o == null) {
-      return st.object
-    }
-    return void 0
-  }
-
-  anyValue (s, p, o, g) {
-    var y = this.any(s, p, o, g)
-    return y ? y.value : void 0
-  }
-
-  anyJS (s, p, o, g) {
-    var y = this.any(s, p, o, g)
-    return y ? Node.toJS(y) : void 0
-  }
-
-  anyStatementMatching (subj, pred, obj, why) {
-    var x = this.statementsMatching(subj, pred, obj, why, true)
-    if (!x || x.length === 0) {
-      return undefined
-    }
-    return x[0]
-  }
-
-  /**
-   * Returns a unique index-safe identifier for the given term.
-   *
-   * Falls back to the rdflib hashString implementation if the given factory doesn't support id.
-   */
-  id (term) {
-    return this.rdfFactory.id(term)
-  }
-
-  /** Search the Store
-   *
-   * This is really a teaching method as to do this properly you would use IndexedFormula
-   *
-   * @param {Node} subject - A node to search for as subject, or if null, a wildcard
-   * @param {Node} predicate - A node to search for as predicate, or if null, a wildcard
-   * @param {Node} object - A node to search for as object, or if null, a wildcard
-   * @param {Node} graph - A node to search for as graph, or if null, a wildcard
-   * @param {Boolean} justOne - flag - stop when found one rather than get all of them?
-   * @returns {Array<Node>} - An array of nodes which match the wildcard position
-   */
-  statementsMatching (subj, pred, obj, why, justOne) {
-    let found = this.statements.filter(st =>
-      (!subj || subj.equals(st.subject)) &&
-      (!pred || pred.equals(st.predicate)) &&
-      (!obj || subj.equals(st.object)) &&
-      (!why || why.equals(st.subject))
-     )
-    return found
-  }
-  /**
-   * Finds the types in the list which have no *stored* subtypes
-   * These are a set of classes which provide by themselves complete
-   * information -- the other classes are redundant for those who
-   * know the class DAG.
-   */
-  bottomTypeURIs (types) {
-    var bots
-    var bottom
-    var elt
-    var i
-    var k
-    var len
-    var ref
-    var subs
-    var v
-    bots = []
-    for (k in types) {
-      if (!types.hasOwnProperty(k)) continue
-      v = types[k]
-      subs = this.each(void 0, this.sym('http://www.w3.org/2000/01/rdf-schema#subClassOf'), this.sym(k))
-      bottom = true
-      i = 0
-      for (len = subs.length; i < len; i++) {
-        elt = subs[i]
-        ref = elt.uri
-        if (ref in types) { // the subclass is one we know
-          bottom = false
-          break
-        }
-      }
-      if (bottom) {
-        bots[k] = v
-      }
-    }
-    return bots
-  }
-  collection () {
-    return new Collection()
-  }
-
-  /** Follow links from one node, using one wildcard
-  *
-  * For example, each(me, knows, null, profile)  - people I know accoring to my profile .
-  * each(me, knows, null, null)  - people I know accoring to anything in store .
-  * each(null, knows, me, null)  - people who know me accoring to anything in store .
-  *
-  * @param {Node} subject - A node to search for as subject, or if null, a wildcard
-  * @param {Node} predicate - A node to search for as predicate, or if null, a wildcard
-  * @param {Node} object - A node to search for as object, or if null, a wildcard
-  * @param {Node} graph - A node to search for as graph, or if null, a wildcard
-  * @returns {Array<Node>} - An array of nodes which match the wildcard position
-  */
-  each (s, p, o, g) {
-    var elt, i, l, m, q
-    var len, len1, len2, len3
-    var results = []
-    var sts = this.statementsMatching(s, p, o, g, false)
-    if (s == null) {
-      for (i = 0, len = sts.length; i < len; i++) {
-        elt = sts[i]
-        results.push(elt.subject)
-      }
-    } else if (p == null) {
-      for (l = 0, len1 = sts.length; l < len1; l++) {
-        elt = sts[l]
-        results.push(elt.predicate)
-      }
-    } else if (o == null) {
-      for (m = 0, len2 = sts.length; m < len2; m++) {
-        elt = sts[m]
-        results.push(elt.object)
-      }
-    } else if (g == null) {
-      for (q = 0, len3 = sts.length; q < len3; q++) {
-        elt = sts[q]
-        results.push(elt.why)
-      }
-    }
-    return results
-  }
-  equals (other) {
-    if (!other) {
-      return false
-    }
-    return this.hashString() === other.hashString()
-  }
-  /*
-  For thisClass or any subclass, anything which has it is its type
-  or is the object of something which has the type as its range, or subject
-  of something which has the type as its domain
-  We don't bother doing subproperty (yet?)as it doesn't seeem to be used much.
-  Get all the Classes of which we can RDFS-infer the subject is a member
-  @returns a hash of URIs
-  */
-
-  /**
-   * For thisClass or any subclass, anything which has it is its type
-   * or is the object of something which has the type as its range, or subject
-   * of something which has the type as its domain
-   * We don't bother doing subproperty (yet?)as it doesn't seeem to be used
-   * much.
-   * Get all the Classes of which we can RDFS-infer the subject is a member
-   * @return a hash of URIs
-   */
-  findMembersNT (thisClass) {
-    var i
-    var l
-    var len
-    var len1
-    var len2
-    var len3
-    var len4
-    var m
-    var members
-    var pred
-    var q
-    var ref
-    var ref1
-    var ref2
-    var ref3
-    var ref4
-    var ref5
-    var seeds
-    var st
-    var t
-    var u
-    seeds = {}
-    seeds[thisClass.toNT()] = true
-    members = {}
-    ref = this.transitiveClosure(seeds, this.sym('http://www.w3.org/2000/01/rdf-schema#subClassOf'), true)
-    for (t in ref) {
-      if (!ref.hasOwnProperty(t)) continue
-      ref1 = this.statementsMatching(void 0,
-        this.sym('http://www.w3.org/1999/02/22-rdf-syntax-ns#type'),
-        this.fromNT(t))
-      for (i = 0, len = ref1.length; i < len; i++) {
-        st = ref1[i]
-        members[st.subject.toNT()] = st
-      }
-      ref2 = this.each(void 0,
-        this.sym('http://www.w3.org/2000/01/rdf-schema#domain'),
-        this.fromNT(t))
-      for (l = 0, len1 = ref2.length; l < len1; l++) {
-        pred = ref2[l]
-        ref3 = this.statementsMatching(void 0, pred)
-        for (m = 0, len2 = ref3.length; m < len2; m++) {
-          st = ref3[m]
-          members[st.subject.toNT()] = st
-        }
-      }
-      ref4 = this.each(void 0,
-        this.sym('http://www.w3.org/2000/01/rdf-schema#range'),
-        this.fromNT(t))
-      for (q = 0, len3 = ref4.length; q < len3; q++) {
-        pred = ref4[q]
-        ref5 = this.statementsMatching(void 0, pred)
-        for (u = 0, len4 = ref5.length; u < len4; u++) {
-          st = ref5[u]
-          members[st.object.toNT()] = st
-        }
-      }
-    }
-    return members
-  }
-  findMemberURIs (subject) {
-    return this.NTtoURI(this.findMembersNT(subject))
-  }
-  /**
-   * Get all the Classes of which we can RDFS-infer the subject is a superclass
-   * Returns a hash table where key is NT of type and value is statement why we
-   * think so.
-   * Does NOT return terms, returns URI strings.
-   * We use NT representations in this version because they handle blank nodes.
-   */
-  findSubClassesNT (subject) {
-    var types = {}
-    types[subject.toNT()] = true
-    return this.transitiveClosure(types,
-      this.sym('http://www.w3.org/2000/01/rdf-schema#subClassOf'), true)
-  }
-  /**
-   * Get all the Classes of which we can RDFS-infer the subject is a subclass
-   * @param {NamedNode} subject - The thing whose classes are to be found
-   * @returns a hash table where key is NT of type and value is statement why we
-   * think so.
-   * Does NOT return terms, returns URI strings.
-   * We use NT representations in this version because they handle blank nodes.
-   */
-  findSuperClassesNT (subject) {
-    var types = {}
-    types[subject.toNT()] = true
-    return this.transitiveClosure(types,
-      this.sym('http://www.w3.org/2000/01/rdf-schema#subClassOf'), false)
-  }
-  /**
-   * Get all the Classes of which we can RDFS-infer the subject is a member
-   * todo: This will loop is there is a class subclass loop (Sublass loops are
-   * not illegal)
-   * @param {NamedNode} subject - The thing whose classes are to be found
-   * @returns a hash table where key is NT of type and value is statement why we think so.
-   * Does NOT return terms, returns URI strings.
-   * We use NT representations in this version because they handle blank nodes.
-   */
-  findTypesNT (subject) {
-    var domain
-    var i
-    var l
-    var len
-    var len1
-    var len2
-    var len3
-    var m
-    var q
-    var range
-    var rdftype
-    var ref
-    var ref1
-    var ref2
-    var ref3
-    var st
-    var types
-    rdftype = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#type'
-    types = []
-    ref = this.statementsMatching(subject, void 0, void 0)
-    for (i = 0, len = ref.length; i < len; i++) {
-      st = ref[i]
-      if (st.predicate.uri === rdftype) {
-        types[st.object.toNT()] = st
-      } else {
-        ref1 = this.each(st.predicate, this.sym('http://www.w3.org/2000/01/rdf-schema#domain'))
-        for (l = 0, len1 = ref1.length; l < len1; l++) {
-          range = ref1[l]
-          types[range.toNT()] = st
-        }
-      }
-    }
-    ref2 = this.statementsMatching(void 0, void 0, subject)
-    for (m = 0, len2 = ref2.length; m < len2; m++) {
-      st = ref2[m]
-      ref3 = this.each(st.predicate, this.sym('http://www.w3.org/2000/01/rdf-schema#range'))
-      for (q = 0, len3 = ref3.length; q < len3; q++) {
-        domain = ref3[q]
-        types[domain.toNT()] = st
-      }
-    }
-    return this.transitiveClosure(types, this.sym('http://www.w3.org/2000/01/rdf-schema#subClassOf'), false)
-  }
-  findTypeURIs (subject) {
-    return this.NTtoURI(this.findTypesNT(subject))
-  }
-  /** Trace statements which connect directly, or through bnodes
-   *
-   * @param {NamedNode} subject - The node to start looking for statments
-   * @param {NamedNode} doc - The document to be searched, or null to search all documents
-   * @returns an array of statements, duplicate statements are suppresssed.
-   */
-  connectedStatements (subject, doc, excludePredicateURIs) {
-    excludePredicateURIs = excludePredicateURIs || []
-    var todo = [subject]
-    var done = []
-    var doneArcs = []
-    var result = []
-    var self = this
-    var follow = function (x) {
-      var queue = function (x) {
-        if (x.termType === 'BlankNode' && !done[x.value]) {
-          done[x.value] = true
-          todo.push(x)
-        }
-      }
-      var sts = self.statementsMatching(null, null, x, doc)
-        .concat(self.statementsMatching(x, null, null, doc))
-      sts = sts.filter(function (st) {
-        if (excludePredicateURIs[st.predicate.uri]) return false
-        var hash = st.toNT()
-        if (doneArcs[hash]) return false
-        doneArcs[hash] = true
-        return true
-      }
-      )
-      sts.forEach(function (st, i) {
-        queue(st.subject)
-        queue(st.object)
-      })
-      result = result.concat(sts)
-    }
-    while (todo.length) {
-      follow(todo.shift())
-    }
-    // console.log('' + result.length + ' statements about ' + subject)
-    return result
-  }
-
-  formula () {
-    return new Formula()
-  }
-  /**
-   * Transforms an NTriples string format into a Node.
-   * The bnode bit should not be used on program-external values; designed
-   * for internal work such as storing a bnode id in an HTML attribute.
-   * This will only parse the strings generated by the vaious toNT() methods.
-   */
-  fromNT (str) {
-    var dt, k, lang
-    switch (str[0]) {
-      case '<':
-        return this.sym(str.slice(1, -1))
-      case '"':
-        lang = void 0
-        dt = void 0
-        k = str.lastIndexOf('"')
-        if (k < str.length - 1) {
-          if (str[k + 1] === '@') {
-            lang = str.slice(k + 2)
-          } else if (str.slice(k + 1, k + 3) === '^^') {
-            dt = this.fromNT(str.slice(k + 3))
-          } else {
-            throw new Error("Can't convert string from NT: " + str)
-          }
-        }
-        str = str.slice(1, k)
-        str = str.replace(/\\"/g, '"')
-        str = str.replace(/\\n/g, '\n')
-        str = str.replace(/\\\\/g, '\\')
-        return this.literal(str, lang || dt)
-      case '_':
-        return this.rdfFactory.blankNode(str.slice(2))
-      case '?':
-        return new Variable(str.slice(1))
-    }
-    throw new Error("Can't convert from NT: " + str)
-  }
-
-  holds (s, p, o, g) {
-    var i
-    if (arguments.length === 1) {
-      if (!s) {
-        return true
-      }
-      if (s instanceof Array) {
-        for (i = 0; i < s.length; i++) {
-          if (!this.holds(s[i])) {
-            return false
-          }
-        }
-        return true
-      } else if (isStatement(s)) {
-        return this.holds(s.subject, s.predicate, s.object, s.why)
-      } else if (s.statements) {
-        return this.holds(s.statements)
-      }
-    }
-
-    var st = this.anyStatementMatching(s, p, o, g)
-    return st != null
-  }
-  holdsStatement (st) {
-    return this.holds(st.subject, st.predicate, st.object, st.why)
-  }
-
-  /**
-   * Used by the n3parser to generate list elements
-   * @param values - The values of the collection
-   * @param context - The store
-   * @return {BlankNode|Collection} - The term for the statement
-   */
-  list (values, context) {
-    if (context.rdfFactory.supports["COLLECTIONS"]) {
-      const collection = context.rdfFactory.collection()
-      values.forEach(function (val) {
-        collection.append(val)
-      })
-      return collection
-    } else {
-      const node = context.rdfFactory.blankNode()
-      const statements = arrayToStatements(context.rdfFactory, node, values)
-      context.addAll(statements)
-      return node
-    }
-  }
-  /**
-   * transform a collection of NTriple URIs into their URI strings
-   * @param t some iterable colletion of NTriple URI strings
-   * @return a collection of the URIs as strings
-   * todo: explain why it is important to go through NT
-   */
-  NTtoURI (t) {
-    var k, v
-    var uris = {}
-    for (k in t) {
-      if (!t.hasOwnProperty(k)) continue
-      v = t[k]
-      if (k[0] === '<') {
-        uris[k.slice(1, -1)] = v
-      }
-    }
-    return uris
-  }
-  serialize (base, contentType, provenance) {
-    var documentString
-    var sts
-    var sz
-    sz = Serializer(this)
-    sz.suggestNamespaces(this.namespaces)
-    sz.setBase(base)
-    if (provenance) {
-      sts = this.statementsMatching(void 0, void 0, void 0, provenance)
-    } else {
-      sts = this.statements
-    }
-    switch (
-    contentType != null ? contentType : 'text/n3') {
-      case 'application/rdf+xml':
-        documentString = sz.statementsToXML(sts)
-        break
-      case 'text/n3':
-      case 'text/turtle':
-        documentString = sz.statementsToN3(sts)
-        break
-      default:
-        throw new Error('serialize: Content-type ' + contentType +
-          ' not supported.')
-    }
-    return documentString
-  }
-  substitute (bindings) {
-    var statementsCopy = this.statements.map(function (ea) {
-      return ea.substitute(bindings)
-    })
-    console.log('Formula subs statmnts:' + statementsCopy)
-    var y = new Formula()
-    y.add(statementsCopy)
-    console.log('indexed-form subs formula:' + y)
-    return y
-  }
-  sym (uri, name) {
-    if (name) {
-      throw new Error('This feature (kb.sym with 2 args) is removed. Do not assume prefix mappings.')
-    }
-    return this.rdfFactory.namedNode(uri)
-  }
-  the (s, p, o, g) {
-    var x = this.any(s, p, o, g)
-    if (x == null) {
-      log.error('No value found for the() {' + s + ' ' + p + ' ' + o + '}.')
-    }
-    return x
-  }
-  /**
-   * RDFS Inference
-   * These are hand-written implementations of a backward-chaining reasoner
-   * over the RDFS axioms.
-   * @param seeds {Object} a hash of NTs of classes to start with
-   * @param predicate The property to trace though
-   * @param inverse trace inverse direction
-   */
-  transitiveClosure (seeds, predicate, inverse) {
-    var elt, i, len, s, sups, t
-    var agenda = {}
-    Object.assign(agenda, seeds)  // make a copy
-    var done = {}  // classes we have looked up
-    while (true) {
-      t = (function () {
-        for (var p in agenda) {
-          if (!agenda.hasOwnProperty(p)) continue
-          return p
-        }
-      })()
-      if (t == null) {
-        return done
-      }
-      sups = inverse ? this.each(void 0, predicate, this.fromNT(t)) : this.each(this.fromNT(t), predicate)
-      for (i = 0, len = sups.length; i < len; i++) {
-        elt = sups[i]
-        s = elt.toNT()
-        if (s in done) {
-          continue
-        }
-        if (s in agenda) {
-          continue
-        }
-        agenda[s] = agenda[t]
-      }
-      done[t] = agenda[t]
-      delete agenda[t]
-    }
-  }
-  /**
-   * Finds the types in the list which have no *stored* supertypes
-   * We exclude the universal class, owl:Things and rdf:Resource, as it is
-   * information-free.
-   */
-  topTypeURIs (types) {
-    var i
-    var j
-    var k
-    var len
-    var n
-    var ref
-    var tops
-    var v
-    tops = []
-    for (k in types) {
-      if (!types.hasOwnProperty(k)) continue
-      v = types[k]
-      n = 0
-      ref = this.each(this.sym(k), this.sym('http://www.w3.org/2000/01/rdf-schema#subClassOf'))
-      for (i = 0, len = ref.length; i < len; i++) {
-        j = ref[i]
-        if (j.uri !== 'http://www.w3.org/2000/01/rdf-schema#Resource') {
-          n++
-          break
-        }
-      }
-      if (!n) {
-        tops[k] = v
-      }
-    }
-    if (tops['http://www.w3.org/2000/01/rdf-schema#Resource']) {
-      delete tops['http://www.w3.org/2000/01/rdf-schema#Resource']
-    }
-    if (tops['http://www.w3.org/2002/07/owl#Thing']) {
-      delete tops['http://www.w3.org/2002/07/owl#Thing']
-    }
-    return tops
-  }
-  toString () {
-    return '{' + this.statements.join('\n') + '}'
-  }
-  whether (s, p, o, g) {
-    return this.statementsMatching(s, p, o, g, false).length
-  }
-}
-Formula.termType = 'Graph'
-
-Formula.prototype.classOrder = ClassOrder['Graph']
-Formula.prototype.isVar = 0
-
-Formula.prototype.ns = Namespace
-Formula.prototype.variable = name => new Variable(name)
diff --git a/src/formula.ts b/src/formula.ts
new file mode 100644
index 000000000..26ce0e691
--- /dev/null
+++ b/src/formula.ts
@@ -0,0 +1,934 @@
+import ClassOrder from './class-order'
+import Collection from './collection'
+import CanonicalDataFactory from './factories/canonical-data-factory'
+import log from './log'
+import RDFlibNamedNode from './named-node'
+import Namespace from './namespace'
+import Node from './node-internal'
+import Serializer from './serialize'
+import Statement from './statement'
+import {
+  Bindings,
+  GraphTermType,
+} from './types'
+import { isStatement } from './utils/terms'
+import Variable from './variable'
+import {
+  Indexable,
+  TFIDFactoryTypes,
+} from './factories/factory-types'
+import { appliedFactoryMethods, arrayToStatements } from './utils'
+import {
+  BlankNode,
+  RdfJsDataFactory,
+  Quad_Graph,
+  Quad_Object,
+  Quad_Predicate,
+  Quad,
+  Quad_Subject,
+  Term,
+} from './tf-types'
+import Fetcher from './fetcher'
+
+export interface FormulaOpts {
+  dataCallback?: (q: Quad) => void
+  rdfArrayRemove?: (arr: Quad[], q: Quad) => void
+  rdfFactory?: RdfJsDataFactory
+}
+
+interface BooleanMap {
+  [uri: string]: boolean;
+}
+
+interface MembersMap {
+  [uri: string]: Quad;
+}
+
+interface UriMap {
+  [uri: string]: string;
+}
+
+/**
+ * A formula, or store of RDF statements
+ */
+export default class Formula extends Node {
+  termType: typeof GraphTermType = GraphTermType
+
+  classOrder = ClassOrder.Graph
+
+  /** The additional constraints */
+  constraints: ReadonlyArray<any>;
+
+  /**
+   * The accompanying fetcher instance.
+   *
+   * Is set by the fetcher when initialized.
+   */
+  fetcher?: Fetcher
+
+  initBindings: ReadonlyArray<any>
+
+  isVar = 0
+
+  /**
+   * A namespace for the specified namespace's URI
+   * @param nsuri The URI for the namespace
+   */
+  ns = Namespace
+
+  optional: ReadonlyArray<any>
+
+  /** The factory used to generate statements and terms */
+  rdfFactory: any
+
+  /** The stored statements */
+  statements: Quad[];
+
+  /**
+   * Initializes this formula
+   * @constructor
+   * @param statements - Initial array of statements
+   * @param constraints - initial array of constraints
+   * @param initBindings - initial bindings used in Query
+   * @param optional - optional
+   * @param opts
+   * @param opts.rdfFactory - The rdf factory that should be used by the store
+*/
+  constructor (
+    statements?: Quad[],
+    constraints?: ReadonlyArray<any>,
+    initBindings?: ReadonlyArray<any>,
+    optional?: ReadonlyArray<any>,
+    opts: FormulaOpts = {}
+    ) {
+    super('')
+    this.statements = statements || []
+    this.constraints = constraints || []
+    this.initBindings = initBindings || []
+    this.optional = optional || []
+
+    this.rdfFactory = (opts && opts.rdfFactory) || CanonicalDataFactory
+    // Enable default factory methods on this while preserving factory context.
+    for(const factoryMethod of appliedFactoryMethods) {
+      this[factoryMethod] = (...args) => this.rdfFactory[factoryMethod](...args)
+    }
+  }
+
+  /** Add a statement from its parts
+   * @param subject - the first part of the statement
+   * @param predicate - the second part of the statement
+   * @param object - the third part of the statement
+   * @param graph - the last part of the statement
+   */
+  add (
+    subject: Quad_Subject,
+    predicate: Quad_Predicate,
+    object: Quad_Object,
+    graph?: Quad_Graph
+  ): number {
+    return this.statements
+      .push(this.rdfFactory.quad(subject, predicate, object, graph))
+  }
+
+  /** Add a statment object
+   * @param {Statement} statement - An existing constructed statement to add
+   */
+  addStatement (statement: Quad): number {
+    return this.statements.push(statement)
+  }
+
+  /** @deprecated use {this.rdfFactory.blankNode} instead */
+  bnode (id?: string): BlankNode {
+    return this.rdfFactory.blankNode(id)
+  }
+
+  /**
+   * Adds all the statements to this formula
+   * @param statements - A collection of statements
+   */
+  addAll (statements: Quad[]): void {
+    statements.forEach(quad => {
+      this.add(quad.subject, quad.predicate, quad.object, quad.graph)
+    })
+  }
+
+  /** Follow link from one node, using one wildcard, looking for one
+  *
+  * For example, any(me, knows, null, profile)  - a person I know accoring to my profile .
+  * any(me, knows, null, null)  - a person I know accoring to anything in store .
+  * any(null, knows, me, null)  - a person who know me accoring to anything in store .
+  *
+  * @param s - A node to search for as subject, or if null, a wildcard
+  * @param p - A node to search for as predicate, or if null, a wildcard
+  * @param o - A node to search for as object, or if null, a wildcard
+  * @param g - A node to search for as graph, or if null, a wildcard
+  * @returns A node which match the wildcard position, or null
+  */
+  any(
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null
+  ): Term | null | undefined {
+    const st = this.anyStatementMatching(s, p, o, g)
+    if (st == null) {
+      return void 0
+    } else if (s == null) {
+      return st.subject
+    } else if (p == null) {
+      return st.predicate
+    } else if (o == null) {
+      return st.object
+    }
+
+    return void 0
+  }
+
+  /**
+   * Gets the value of a node that matches the specified pattern
+   * @param s The subject
+   * @param p The predicate
+   * @param o The object
+   * @param g The graph that contains the statement
+   */
+  anyValue(
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null
+  ): string | void {
+    const y = this.any(s, p, o, g)
+    return y ? y.value : void 0
+  }
+
+  /**
+   * Gets the first JavaScript object equivalent to a node based on the specified pattern
+   * @param s The subject
+   * @param p The predicate
+   * @param o The object
+   * @param g The graph that contains the statement
+   */
+  anyJS(
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null
+  ): any {
+    const y = this.any(s, p, o, g)
+    return y ? Node.toJS(y) : void 0
+  }
+
+  /**
+   * Gets the first statement that matches the specified pattern
+   */
+  anyStatementMatching(
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null
+  ): Quad | undefined {
+    let x = this.statementsMatching(s, p, o, g, true)
+    if (!x || x.length === 0) {
+      return undefined
+    }
+
+    return x[0]
+  }
+
+  /**
+   * Returns a unique index-safe identifier for the given term.
+   *
+   * Falls back to the rdflib hashString implementation if the given factory doesn't support id.
+   */
+  id (term: TFIDFactoryTypes): Indexable {
+    return this.rdfFactory.id(term)
+  }
+
+  /**
+   * Search the Store
+   * This is really a teaching method as to do this properly you would use IndexedFormula
+   *
+   * @param s - A node to search for as subject, or if null, a wildcard
+   * @param p - A node to search for as predicate, or if null, a wildcard
+   * @param o - A node to search for as object, or if null, a wildcard
+   * @param g - A node to search for as graph, or if null, a wildcard
+   * @param justOne - flag - stop when found one rather than get all of them?
+   * @returns {Array<Node>} - An array of nodes which match the wildcard position
+   */
+  statementsMatching<JustOne extends boolean = false>(
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null,
+    justOne?: boolean
+  ): Quad[] {
+    const sts = this.statements.filter(st =>
+      (!s || s.equals(st.subject)) &&
+      (!p || p.equals(st.predicate)) &&
+      (!o || o.equals(st.object)) &&
+      (!g || g.equals(st.subject))
+    )
+
+    if (justOne) {
+      return sts.length === 0 ? [] : [sts[0]]
+    }
+
+    return sts
+  }
+
+  /**
+   * Finds the types in the list which have no *stored* subtypes
+   * These are a set of classes which provide by themselves complete
+   * information -- the other classes are redundant for those who
+   * know the class DAG.
+   * @param types A map of the types
+   */
+  bottomTypeURIs (types) {
+    let bots
+    let bottom
+    let elt
+    let i
+    let len
+    let ref
+    let subs
+    let v
+    bots = []
+    for (let k in types) {
+      if (!types.hasOwnProperty(k)) continue
+      v = types[k]
+      subs = this.each(
+        void 0,
+        this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#subClassOf'),
+        this.rdfFactory.namedNode(k)
+      )
+      bottom = true
+      i = 0
+      for (len = subs.length; i < len; i++) {
+        elt = subs[i]
+        ref = elt.uri
+        if (ref in types) { // the subclass is one we know
+          bottom = false
+          break
+        }
+      }
+      if (bottom) {
+        bots[k] = v
+      }
+    }
+    return bots
+  }
+
+  /** Creates a new collection */
+  collection (): Collection {
+    return new Collection()
+  }
+
+  /** Follow links from one node, using one wildcard.
+  *
+  * For example, each(me, knows, null, profile)  - people I know accoring to my profile .
+  * each(me, knows, null, null)  - people I know accoring to anything in store .
+  * each(null, knows, me, null)  - people who know me accoring to anything in store .
+  *
+  * @param s - A node to search for as subject, or if null, a wildcard
+  * @param p - A node to search for as predicate, or if null, a wildcard
+  * @param o - A node to search for as object, or if null, a wildcard
+  * @param g - A node to search for as graph, or if null, a wildcard
+  * @returns {Array<Node>} - An array of nodes which match the wildcard position
+  */
+  each(
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null
+  ): Term[] {
+    const results: Term[] = []
+    let sts = this.statementsMatching(s, p, o, g, false)
+    if (s == null) {
+      for (let i = 0, len = sts.length; i < len; i++) {
+        results.push(sts[i].subject)
+      }
+    } else if (p == null) {
+      for (let l = 0, len1 = sts.length; l < len1; l++) {
+        results.push(sts[l].predicate)
+      }
+    } else if (o == null) {
+      for (let m = 0, len2 = sts.length; m < len2; m++) {
+        results.push(sts[m].object)
+      }
+    } else if (g == null) {
+      for (let q = 0, len3 = sts.length; q < len3; q++) {
+        results.push(sts[q].graph)
+      }
+    }
+
+    return results
+  }
+
+  /**
+   * Test whether this formula is equals to {other}
+   * @param other - The other formula
+   */
+  equals(other: Formula): boolean {
+    if (!other) {
+      return false
+    }
+    return this.hashString() === other.hashString()
+  }
+
+  /**
+   * For thisClass or any subclass, anything which has it is its type
+   * or is the object of something which has the type as its range, or subject
+   * of something which has the type as its domain
+   * We don't bother doing subproperty (yet?)as it doesn't seeem to be used
+   * much.
+   * Get all the Classes of which we can RDFS-infer the subject is a member
+   * @return a hash of URIs
+   */
+  findMembersNT (thisClass) {
+    let len2: number
+    let len4: number
+    let m: number
+    let members: MembersMap
+    let pred: Quad_Predicate
+    let ref
+    let ref1: Quad[]
+    let ref2: Term[]
+    let ref3: Quad[]
+    let ref4: Term[]
+    let ref5: Quad[]
+    let seeds
+    let st
+    let u: number
+    seeds = {}
+    seeds[thisClass.toNT()] = true
+    members = {}
+    ref = this.transitiveClosure(seeds, this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#subClassOf'), true)
+    for (let t in ref) {
+      if (!ref.hasOwnProperty(t)) continue
+      ref1 = this.statementsMatching(void 0,
+        this.rdfFactory.namedNode('http://www.w3.org/1999/02/22-rdf-syntax-ns#type'),
+        this.fromNT(t))
+      for (let i = 0, len = ref1.length; i < len; i++) {
+        st = ref1[i]
+        members[st.subject.toNT()] = st
+      }
+      ref2 = this.each(void 0,
+        this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#domain'),
+        this.fromNT(t))
+      for (let l = 0, len1 = ref2.length; l < len1; l++) {
+        pred = ref2[l] as Quad_Predicate
+        ref3 = this.statementsMatching(void 0, pred)
+        for (m = 0, len2 = ref3.length; m < len2; m++) {
+          st = ref3[m]
+          members[st.subject.toNT()] = st
+        }
+      }
+      ref4 = this.each(void 0,
+        this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#range'),
+        this.fromNT(t))
+      for (let q = 0, len3 = ref4.length; q < len3; q++) {
+        pred = ref4[q] as Quad_Predicate
+        ref5 = this.statementsMatching(void 0, pred)
+        for (u = 0, len4 = ref5.length; u < len4; u++) {
+          st = ref5[u]
+          members[st.object.toNT()] = st
+        }
+      }
+    }
+
+    return members
+  }
+
+  /**
+   * For thisClass or any subclass, anything which has it is its type
+   * or is the object of something which has the type as its range, or subject
+   * of something which has the type as its domain
+   * We don't bother doing subproperty (yet?)as it doesn't seeem to be used
+   * much.
+   * Get all the Classes of which we can RDFS-infer the subject is a member
+   * @param subject - A named node
+   */
+  findMemberURIs(subject: Node): UriMap {
+    return this.NTtoURI(this.findMembersNT(subject))
+  }
+
+  /**
+   * Get all the Classes of which we can RDFS-infer the subject is a superclass
+   * Returns a hash table where key is NT of type and value is statement why we
+   * think so.
+   * Does NOT return terms, returns URI strings.
+   * We use NT representations in this version because they handle blank nodes.
+   */
+  findSubClassesNT(subject: Node): { [uri: string]: boolean } {
+    let types = {}
+    types[subject.toNT()] = true
+    return this.transitiveClosure(
+      types,
+      this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#subClassOf'),
+      true
+    )
+  }
+
+  /**
+   * Get all the Classes of which we can RDFS-infer the subject is a subclass
+   * @param {RDFlibNamedNode} subject - The thing whose classes are to be found
+   * @returns a hash table where key is NT of type and value is statement why we
+   * think so.
+   * Does NOT return terms, returns URI strings.
+   * We use NT representations in this version because they handle blank nodes.
+   */
+  findSuperClassesNT(subject: Node): { [uri: string]: boolean } {
+    let types = {}
+    types[subject.toNT()] = true
+    return this.transitiveClosure(types,
+      this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#subClassOf'), false)
+  }
+
+  /**
+   * Get all the Classes of which we can RDFS-infer the subject is a member
+   * todo: This will loop is there is a class subclass loop (Sublass loops are
+   * not illegal)
+   * @param {RDFlibNamedNode} subject - The thing whose classes are to be found
+   * @returns a hash table where key is NT of type and value is statement why we think so.
+   * Does NOT return terms, returns URI strings.
+   * We use NT representations in this version because they handle blank nodes.
+   */
+  findTypesNT (subject) {
+    let domain
+    let range
+    let rdftype
+    let ref
+    let ref1
+    let ref2
+    let ref3
+    let st
+    let types
+    rdftype = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#type'
+    types = []
+    ref = this.statementsMatching(subject, void 0, void 0)
+    for (let i = 0, len = ref.length; i < len; i++) {
+      st = ref[i]
+      if (st.predicate.uri === rdftype) {
+        types[st.object.toNT()] = st
+      } else {
+        ref1 = this.each(
+          st.predicate,
+          this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#domain')
+        )
+        for (let l = 0, len1 = ref1.length; l < len1; l++) {
+          range = ref1[l]
+          types[range.toNT()] = st
+        }
+      }
+    }
+    ref2 = this.statementsMatching(void 0, void 0, subject)
+    for (let m = 0, len2 = ref2.length; m < len2; m++) {
+      st = ref2[m]
+      ref3 = this.each(
+        st.predicate,
+        this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#range')
+      )
+      for (let q = 0, len3 = ref3.length; q < len3; q++) {
+        domain = ref3[q]
+        types[domain.toNT()] = st
+      }
+    }
+    return this.transitiveClosure(
+      types,
+      this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#subClassOf'),
+      false
+    )
+  }
+
+  /**
+   * Get all the Classes of which we can RDFS-infer the subject is a member
+   * todo: This will loop is there is a class subclass loop (Sublass loops are
+   * not illegal)
+   * Returns a hash table where key is NT of type and value is statement why we
+   * think so.
+   * Does NOT return terms, returns URI strings.
+   * We use NT representations in this version because they handle blank nodes.
+   * @param subject - A subject node
+   */
+  findTypeURIs(subject: Quad_Subject): UriMap {
+    return this.NTtoURI(this.findTypesNT(subject))
+  }
+
+  /** Trace statements which connect directly, or through bnodes
+   *
+   * @param subject - The node to start looking for statments
+   * @param doc - The document to be searched, or null to search all documents
+   * @returns an array of statements, duplicate statements are suppresssed.
+   */
+  connectedStatements(
+    subject: Quad_Subject,
+    doc: Quad_Graph,
+    excludePredicateURIs?: ReadonlyArray<string>
+  ): Quad[] {
+    excludePredicateURIs = excludePredicateURIs || []
+    let todo = [subject]
+    let done: { [k: string]: boolean } = {}
+    let doneArcs: { [k: string]: boolean }  = {}
+    let result: Quad[] = []
+    let self = this
+    let follow = function (x) {
+      let queue = function (x) {
+        if (x.termType === 'BlankNode' && !done[x.value]) {
+          done[x.value] = true
+          todo.push(x)
+        }
+      }
+      let sts = self.statementsMatching(null, null, x, doc)
+        .concat(self.statementsMatching(x, null, null, doc))
+      sts = sts.filter(function (st): boolean {
+        if (excludePredicateURIs![st.predicate.value]) return false
+        let hash = (st as Statement).toNT()
+        if (doneArcs[hash]) return false
+        doneArcs[hash] = true
+        return true
+      }
+      )
+      sts.forEach(function (st) {
+        queue(st.subject)
+        queue(st.object)
+      })
+      result = result.concat(sts)
+    }
+    while (todo.length) {
+      follow(todo.shift())
+    }
+    // console.log('' + result.length + ' statements about ' + subject)
+    return result
+  }
+
+  /**
+   * Creates a new empty formula
+   *
+   * @param _features - Not applicable, but necessary for typing to pass
+   */
+  formula(_features?: ReadonlyArray<string>): Formula {
+    return new Formula()
+  }
+
+  /**
+   * Transforms an NTriples string format into a Node.
+   * The blank node bit should not be used on program-external values; designed
+   * for internal work such as storing a blank node id in an HTML attribute.
+   * This will only parse the strings generated by the various toNT() methods.
+   */
+  fromNT (str) {
+    let dt, k, lang
+    switch (str[0]) {
+      case '<':
+        return this.sym(str.slice(1, -1))
+      case '"':
+        lang = void 0
+        dt = void 0
+        k = str.lastIndexOf('"')
+        if (k < str.length - 1) {
+          if (str[k + 1] === '@') {
+            lang = str.slice(k + 2)
+          } else if (str.slice(k + 1, k + 3) === '^^') {
+            dt = this.fromNT(str.slice(k + 3))
+          } else {
+            throw new Error("Can't convert string from NT: " + str)
+          }
+        }
+        str = str.slice(1, k)
+        str = str.replace(/\\"/g, '"')
+        str = str.replace(/\\n/g, '\n')
+        str = str.replace(/\\\\/g, '\\')
+        return this.rdfFactory.literal(str, lang || dt)
+      case '_':
+        return this.rdfFactory.blankNode(str.slice(2))
+      case '?':
+        return new Variable(str.slice(1))
+    }
+    throw new Error("Can't convert from NT: " + str)
+  }
+
+  /** Returns true if this formula holds the specified statement(s) */
+  holds (s: any | any[], p?, o?, g?): boolean {
+    let i
+    if (arguments.length === 1) {
+      if (!s) {
+        return true
+      }
+      if (s instanceof Array) {
+        for (i = 0; i < s.length; i++) {
+          if (!this.holds(s[i])) {
+            return false
+          }
+        }
+        return true
+      } else if (isStatement(s)) {
+        return this.holds(s.subject, s.predicate, s.object, s.graph)
+      } else if (s.statements) {
+        return this.holds(s.statements)
+      }
+    }
+
+    let st = this.anyStatementMatching(s, p, o, g)
+    return st != null
+  }
+
+  /**
+   * Returns true if this formula holds the specified {statement}
+   */
+  holdsStatement (statement) {
+    return this.holds(
+      statement.subject,
+      statement.predicate,
+      statement.object,
+      statement.graph,
+    )
+  }
+
+  /**
+   * Used by the n3parser to generate list elements
+   * @param values - The values of the collection
+   * @param context - The store
+   * @return {BlankNode|Collection} - The term for the statement
+   */
+  list (values, context) {
+    if (context.rdfFactory.supports["COLLECTIONS"]) {
+      const collection = context.rdfFactory.collection()
+      values.forEach(function (val) {
+        collection.append(val)
+      })
+      return collection
+    } else {
+      const node = context.rdfFactory.blankNode()
+      const statements = arrayToStatements(context.rdfFactory, node, values)
+      context.addAll(statements)
+      return node
+    }
+  }
+
+  /**
+   * Transform a collection of NTriple URIs into their URI strings
+   * @param t - Some iterable collection of NTriple URI strings
+   * @return A collection of the URIs as strings
+   * todo: explain why it is important to go through NT
+   */
+  NTtoURI (t) {
+    let k, v
+    let uris = {}
+    for (k in t) {
+      if (!t.hasOwnProperty(k)) continue
+      v = t[k]
+      if (k[0] === '<') {
+        uris[k.slice(1, -1)] = v
+      }
+    }
+    return uris
+  }
+
+  /**
+   * Serializes this formula
+   * @param base - The base string
+   * @param contentType - The content type of the syntax to use
+   * @param provenance - The provenance URI
+   */
+  serialize (base, contentType, provenance) {
+    let documentString
+    let sts
+    let sz
+    sz = Serializer(this)
+    sz.suggestNamespaces(this.ns)
+    sz.setBase(base)
+    if (provenance) {
+      sts = this.statementsMatching(void 0, void 0, void 0, provenance)
+    } else {
+      sts = this.statements
+    }
+    switch (
+    contentType != null ? contentType : 'text/n3') {
+      case 'application/rdf+xml':
+        documentString = sz.statementsToXML(sts)
+        break
+      case 'text/n3':
+      case 'text/turtle':
+        documentString = sz.statementsToN3(sts)
+        break
+      default:
+        throw new Error('serialize: Content-type ' + contentType +
+          ' not supported.')
+    }
+    return documentString
+  }
+
+  /**
+   * Creates a new formula with the substituting bindings applied
+   * @param bindings - The bindings to substitute
+   */
+  //@ts-ignore signature not compatible with Node
+  substitute(bindings: Bindings): Formula {
+    let statementsCopy = this.statements.map(function (ea) {
+      return (ea as Statement).substitute(bindings)
+    })
+    console.log('Formula subs statmnts:' + statementsCopy)
+    const y = new Formula()
+    y.addAll(statementsCopy as Quad[])
+    console.log('indexed-form subs formula:' + y)
+    return y
+  }
+
+  /**
+   * @deprecated use {rdfFactory.namedNode} instead
+   */
+  sym (uri, name?) {
+    if (name) {
+      throw new Error('This feature (kb.sym with 2 args) is removed. Do not assume prefix mappings.')
+    }
+    return this.rdfFactory.namedNode(uri)
+  }
+
+  /**
+   * Gets the node matching the specified pattern. Throws when no match could be made.
+   * @param s - The subject
+   * @param p - The predicate
+   * @param o - The object
+   * @param g - The graph that contains the statement
+   */
+  the (
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null
+  ): Term | null | undefined {
+    let x = this.any(s, p, o, g)
+    if (x == null) {
+      log.error('No value found for the() {' + s + ' ' + p + ' ' + o + '}.')
+    }
+
+    return x
+  }
+
+  /**
+   * RDFS Inference
+   * These are hand-written implementations of a backward-chaining reasoner
+   * over the RDFS axioms.
+   * @param seeds - A hash of NTs of classes to start with
+   * @param predicate - The property to trace though
+   * @param inverse - Trace inverse direction
+   */
+  transitiveClosure(
+    seeds: BooleanMap,
+    predicate: Quad_Predicate,
+    inverse?: boolean
+  ): {
+    [uri: string]: boolean;
+  } {
+    let elt, i, len, s, sups, t
+    let agenda = {}
+    Object.assign(agenda, seeds)  // make a copy
+    let done = {}  // classes we have looked up
+    while (true) {
+      t = (function () {
+        for (let p in agenda) {
+          if (!agenda.hasOwnProperty(p)) continue
+          return p
+        }
+      })()
+      if (t == null) {
+        return done
+      }
+      sups = inverse ?
+        this.each(void 0, predicate, this.fromNT(t))
+        : this.each(this.fromNT(t) as Quad_Predicate, predicate)
+      for (i = 0, len = sups.length; i < len; i++) {
+        elt = sups[i]
+        s = elt.toNT()
+        if (s in done) {
+          continue
+        }
+        if (s in agenda) {
+          continue
+        }
+        agenda[s] = agenda[t]
+      }
+      done[t] = agenda[t]
+      delete agenda[t]
+    }
+  }
+
+  /**
+   * Finds the types in the list which have no *stored* supertypes
+   * We exclude the universal class, owl:Things and rdf:Resource, as it is
+   * information-free.
+   * @param types - The types
+   */
+  topTypeURIs(types: {
+    [id: string]: string | RDFlibNamedNode;
+  }): {
+    [id: string]: string | RDFlibNamedNode;
+  } {
+    let i
+    let j
+    let k
+    let len
+    let n
+    let ref
+    let tops
+    let v
+    tops = []
+    for (k in types) {
+      if (!types.hasOwnProperty(k)) continue
+      v = types[k]
+      n = 0
+      ref = this.each(
+        this.rdfFactory.namedNode(k),
+        this.rdfFactory.namedNode('http://www.w3.org/2000/01/rdf-schema#subClassOf')
+      )
+      for (i = 0, len = ref.length; i < len; i++) {
+        j = ref[i]
+        if (j.uri !== 'http://www.w3.org/2000/01/rdf-schema#Resource') {
+          n++
+          break
+        }
+      }
+      if (!n) {
+        tops[k] = v
+      }
+    }
+    if (tops['http://www.w3.org/2000/01/rdf-schema#Resource']) {
+      delete tops['http://www.w3.org/2000/01/rdf-schema#Resource']
+    }
+    if (tops['http://www.w3.org/2002/07/owl#Thing']) {
+      delete tops['http://www.w3.org/2002/07/owl#Thing']
+    }
+    return tops
+  }
+
+  /**
+   * Serializes this formula to a string
+   */
+  toString(): string {
+    return '{' + this.statements.join('\n') + '}'
+  }
+
+  /**
+   * Gets a new variable
+   * @param name - The variable's name
+   */
+  public variable(name: string): Variable {
+    return new Variable(name)
+  }
+
+  /**
+   * Gets the number of statements in this formula that matches the specified pattern
+   * @param s - The subject
+   * @param p - The predicate
+   * @param o - The object
+   * @param g - The graph that contains the statement
+   */
+  whether(
+    s?: Quad_Subject | null,
+    p?: Quad_Predicate | null,
+    o?: Quad_Object | null,
+    g?: Quad_Graph | null
+  ): number {
+    return this.statementsMatching(s, p, o, g, false).length
+  }
+}
diff --git a/src/index.ts b/src/index.ts
index f49c6ceeb..5d0b7efef 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,7 +1,6 @@
 import BlankNode from './blank-node'
 import Collection from './collection'
 import * as convert from './convert'
-import DataFactory from './data-factory'
 import Empty from './empty'
 import Fetcher from './fetcher'
 import Formula from './formula'
@@ -27,8 +26,11 @@ import UpdateManager from './update-manager'
 import { UpdatesSocket } from './updates-via'
 import { UpdatesVia } from './updates-via'
 import * as uri from './uri'
-import * as Util from './util'
+import * as Util from './utils-js'
 import Variable from './variable'
+import DataFactory from './factories/rdflib-data-factory'
+
+export * from './utils/terms'
 
 const NextId = BlankNode.nextId
 
@@ -104,3 +106,4 @@ export {
   triple,
   variable,
 }
+export { termValue } from './utils/termValue'
diff --git a/src/jsonldparser.js b/src/jsonldparser.js
index 928414526..0a1818891 100644
--- a/src/jsonldparser.js
+++ b/src/jsonldparser.js
@@ -1,6 +1,6 @@
 import jsonld from 'jsonld'
 
-import { arrayToStatements } from './util'
+import { arrayToStatements } from './utils'
 
 /**
  * Parses json-ld formatted JS objects to a rdf Term.
diff --git a/src/literal.js b/src/literal.js
deleted file mode 100644
index 55ba43ffd..000000000
--- a/src/literal.js
+++ /dev/null
@@ -1,147 +0,0 @@
-'use strict'
-import ClassOrder from './class-order'
-import NamedNode from './named-node'
-import Node from './node-internal'
-import XSD from './xsd-internal'
-
-export default class Literal extends Node {
-  constructor (value, language, datatype) {
-    super()
-    this.termType = Literal.termType
-    this.value = value
-    if (language) {
-      this.lang = language
-      datatype = XSD.langString
-    }
-    // If not specified, a literal has the implied XSD.string default datatype
-    if (datatype) {
-      this.datatype = NamedNode.fromValue(datatype)
-    }
-  }
-  copy () {
-    return new Literal(this.value, this.lang, this.datatype)
-  }
-  equals (other) {
-    if (!other) {
-      return false
-    }
-    return (this.termType === other.termType) &&
-      (this.value === other.value) &&
-      (this.language === other.language) &&
-      ((!this.datatype && !other.datatype) ||
-        (this.datatype && this.datatype.equals(other.datatype)))
-  }
-  get language () {
-    return this.lang
-  }
-  set language (language) {
-    this.lang = language || ''
-  }
-  toNT() {
-    return Literal.toNT(this)
-  }
-  static toNT (literal) {
-    if (typeof literal.value === 'number') {
-      return '' + literal.value
-    } else if (typeof literal.value !== 'string') {
-      throw new Error('Value of RDF literal is not string or number: ' +
-        literal.value)
-    }
-    var str = literal.value
-    str = str.replace(/\\/g, '\\\\')
-    str = str.replace(/\"/g, '\\"')
-    str = str.replace(/\n/g, '\\n')
-    str = '"' + str + '"'
-
-    if (literal.language) {
-      str += '@' + literal.language
-    } else if (!literal.datatype.equals(XSD.string)) {
-      // Only add datatype if it's not a string
-      str += '^^' + literal.datatype.toCanonical()
-    }
-    return str
-  }
-  toString () {
-    return '' + this.value
-  }
-  /**
-   * @method fromBoolean
-   * @static
-   * @param value {Boolean}
-   * @return {Literal}
-   */
-  static fromBoolean (value) {
-    let strValue = value ? '1' : '0'
-    return new Literal(strValue, null, XSD.boolean)
-  }
-  /**
-   * @method fromDate
-   * @static
-   * @param value {Date}
-   * @return {Literal}
-   */
-  static fromDate (value) {
-    if (!(value instanceof Date)) {
-      throw new TypeError('Invalid argument to Literal.fromDate()')
-    }
-    let d2 = function (x) {
-      return ('' + (100 + x)).slice(1, 3)
-    }
-    let date = '' + value.getUTCFullYear() + '-' + d2(value.getUTCMonth() + 1) +
-      '-' + d2(value.getUTCDate()) + 'T' + d2(value.getUTCHours()) + ':' +
-      d2(value.getUTCMinutes()) + ':' + d2(value.getUTCSeconds()) + 'Z'
-    return new Literal(date, null, XSD.dateTime)
-  }
-  /**
-   * @method fromNumber
-   * @static
-   * @param value {Number}
-   * @return {Literal}
-   */
-  static fromNumber (value) {
-    if (typeof value !== 'number') {
-      throw new TypeError('Invalid argument to Literal.fromNumber()')
-    }
-    let datatype
-    const strValue = value.toString()
-    if (strValue.indexOf('e') < 0 && Math.abs(value) <= Number.MAX_SAFE_INTEGER) {
-      datatype = Number.isInteger(value) ? XSD.integer : XSD.decimal
-    } else {
-      datatype = XSD.double
-    }
-    return new Literal(strValue, null, datatype)
-  }
-  /**
-   * @method fromValue
-   * @param value
-   * @return {Literal}
-   */
-  static fromValue (value) {
-    if (typeof value === 'undefined' || value === null) {
-      return value
-    }
-    if (typeof value === 'object' && value.termType) {  // this is a Node instance
-      return value
-    }
-    switch (typeof value) {
-      case 'object':
-        if (value instanceof Date) {
-          return Literal.fromDate(value)
-        }
-      case 'boolean':
-        return Literal.fromBoolean(value)
-      case 'number':
-        return Literal.fromNumber(value)
-      case 'string':
-        return new Literal(value)
-    }
-    throw new Error("Can't make literal from " + value + ' of type ' +
-      typeof value)
-
-  }
-}
-Literal.termType = 'Literal'
-Literal.prototype.classOrder = ClassOrder['Literal']
-Literal.prototype.datatype = XSD.string
-Literal.prototype.lang = ''
-Literal.prototype.isVar = 0
diff --git a/src/literal.ts b/src/literal.ts
new file mode 100644
index 000000000..4e5255f66
--- /dev/null
+++ b/src/literal.ts
@@ -0,0 +1,187 @@
+import ClassOrder from './class-order'
+import RDFlibNamedNode from './named-node'
+import Node from './node-internal'
+import {
+  LiteralTermType,
+  ValueType
+} from './types'
+import { isLiteral } from './utils/terms'
+import XSD from './xsd-internal'
+import { Literal as TFLiteral, Term } from './tf-types'
+
+/**
+ * An RDF literal, containing some value which isn't expressed as an IRI.
+ * @link https://rdf.js.org/data-model-spec/#literal-interface
+ */
+// @ts-ignore Incorrectly extends due to fromValue()
+export default class Literal extends Node implements TFLiteral {
+  termType: typeof LiteralTermType = LiteralTermType
+
+  classOrder = ClassOrder.Literal
+
+  /**
+   * The literal's datatype as a named node
+   */
+  datatype: RDFlibNamedNode = XSD.string
+
+  isVar = 0
+
+  /**
+   * The language for the literal
+   */
+  language: string = ''
+
+  /**
+   * Initializes a literal
+   * @param value - The literal's lexical value
+   * @param language - The language for the literal. Defaults to ''.
+   * @param datatype - The literal's datatype as a named node. Defaults to xsd:string.
+   */
+  constructor (value: string, language?: string | null, datatype?) {
+    super(value)
+
+    if (language) {
+      this.language = language
+      this.datatype = XSD.langString
+    } else if (datatype) {
+      this.datatype = RDFlibNamedNode.fromValue(datatype)
+    } else {
+      this.datatype = XSD.string
+    }
+  }
+
+  /**
+   * Gets a copy of this literal
+   */
+  copy (): Literal {
+    return new Literal(this.value, this.lang, this.datatype)
+  }
+
+  /**
+   * Gets whether two literals are the same
+   * @param other The other statement
+   */
+  equals (other: Term): boolean {
+    if (!other) {
+      return false
+    }
+
+    return (this.termType === other.termType) &&
+      (this.value === other.value) &&
+      (this.language === (other as Literal).language) &&
+      ((!this.datatype && !(other as Literal).datatype) ||
+        (this.datatype && this.datatype.equals((other as Literal).datatype)))
+  }
+
+  /**
+   * The language for the literal
+   * @deprecated use {language} instead
+   */
+  get lang (): string {
+    return this.language
+  }
+
+  set lang (language: string) {
+    this.language = language || ''
+  }
+
+  toNT(): string {
+    return Literal.toNT(this)
+  }
+
+  /** Serializes a literal to an N-Triples string */
+  static toNT (literal: Literal): string {
+    if (typeof literal.value === 'number') {
+      return '' + literal.value
+    } else if (typeof literal.value !== 'string') {
+      throw new Error('Value of RDF literal is not string or number: ' +
+        literal.value)
+    }
+    var str = literal.value
+    str = str.replace(/\\/g, '\\\\')
+    str = str.replace(/\"/g, '\\"')
+    str = str.replace(/\n/g, '\\n')
+    str = '"' + str + '"'
+
+    if (literal.language) {
+      str += '@' + literal.language
+    } else if (!literal.datatype.equals(XSD.string)) {
+      // Only add datatype if it's not a string
+      str += '^^' + literal.datatype.toCanonical()
+    }
+    return str
+  }
+
+  toString () {
+    return '' + this.value
+  }
+
+  /**
+   * Builds a literal node from a boolean value
+   * @param value - The value
+   */
+  static fromBoolean (value: boolean): Literal {
+    let strValue = value ? '1' : '0'
+    return new Literal(strValue, null, XSD.boolean)
+  }
+
+  /**
+   * Builds a literal node from a date value
+   * @param value The value
+   */
+  static fromDate(value: Date): Literal {
+    if (!(value instanceof Date)) {
+      throw new TypeError('Invalid argument to Literal.fromDate()')
+    }
+    let d2 = function (x) {
+      return ('' + (100 + x)).slice(1, 3)
+    }
+    let date = '' + value.getUTCFullYear() + '-' + d2(value.getUTCMonth() + 1) +
+      '-' + d2(value.getUTCDate()) + 'T' + d2(value.getUTCHours()) + ':' +
+      d2(value.getUTCMinutes()) + ':' + d2(value.getUTCSeconds()) + 'Z'
+    return new Literal(date, null, XSD.dateTime)
+  }
+
+  /**
+   * Builds a literal node from a number value
+   * @param value - The value
+   */
+  static fromNumber(value: number): Literal {
+    if (typeof value !== 'number') {
+      throw new TypeError('Invalid argument to Literal.fromNumber()')
+    }
+    let datatype: RDFlibNamedNode
+    const strValue = value.toString()
+    if (strValue.indexOf('e') < 0 && Math.abs(value) <= Number.MAX_SAFE_INTEGER) {
+      datatype = Number.isInteger(value) ? XSD.integer : XSD.decimal
+    } else {
+      datatype = XSD.double
+    }
+    return new Literal(strValue, null, datatype)
+  }
+
+  /**
+   * Builds a literal node from an input value
+   * @param value - The input value
+   */
+  static fromValue<T extends Literal>(value: ValueType): T {
+    if (isLiteral(value)) {
+      return value as T
+    }
+    switch (typeof value) {
+      case 'object':
+        if (value instanceof Date) {
+          return Literal.fromDate(value) as T
+        }
+      case 'boolean':
+        return Literal.fromBoolean(value as boolean) as T
+      case 'number':
+        return Literal.fromNumber(value as number) as T
+      case 'string':
+        return new Literal(value) as T
+    }
+
+    throw new Error("Can't make literal from " + value + ' of type ' +
+      typeof value)
+  }
+}
diff --git a/src/n3parser.js b/src/n3parser.js
index 56152a9a6..779d7c1c9 100644
--- a/src/n3parser.js
+++ b/src/n3parser.js
@@ -5,7 +5,7 @@
 *
 **/
 import * as Uri from './uri'
-import { ArrayIndexOf } from './util'
+import { ArrayIndexOf } from './utils'
 
 export default (function () {
 
diff --git a/src/named-node.js b/src/named-node.js
deleted file mode 100644
index b806386ca..000000000
--- a/src/named-node.js
+++ /dev/null
@@ -1,101 +0,0 @@
-'use strict'
-import ClassOrder from './class-order'
-import Node from './node-internal'
-
-/**
- * @class NamedNode
- * @extends Node
- */
-export default class NamedNode extends Node {
-  /**
-   * @constructor
-   * @param iri {String}
-   */
-  constructor (iri) {
-    super()
-    this.termType = NamedNode.termType
-
-    if (iri && iri.termType === NamedNode.termType) {  // param is a named node
-      iri = iri.value
-    }
-
-    if (!iri) {
-      throw new Error('Missing IRI for NamedNode')
-    }
-
-    if (!iri.includes(':')) {
-      throw new Error('NamedNode IRI "' + iri + '" must be absolute.')
-    }
-
-    if (iri.includes(' ')) {
-      var message = 'Error: NamedNode IRI "' + iri + '" must not contain unencoded spaces.'
-      throw new Error(message)
-    }
-
-    this.value = iri
-  }
-  /**
-   * Returns an $rdf node for the containing directory, ending in slash.
-   */
-  dir () {
-     var str = this.uri.split('#')[0]
-     var p = str.slice(0, -1).lastIndexOf('/')
-     var q = str.indexOf('//')
-     if ((q >= 0 && p < q + 2) || p < 0) return null
-     return new NamedNode(str.slice(0, p + 1))
-   }
-   /**
-    * Returns an NN for the whole web site, ending in slash.
-    * Contrast with the "origin" which does NOT have a trailing slash
-    */
-  site () {
-     var str = this.uri.split('#')[0]
-     var p = str.indexOf('//')
-     if (p < 0) throw new Error('This URI does not have a web site part (origin)')
-     var q = str.indexOf('/', p+2)
-     if (q < 0) {
-       return new NamedNode(str.slice(0) + '/')   // Add slash to a bare origin
-     } else {
-       return new NamedNode(str.slice(0, q + 1))
-     }
-   }
-  doc () {
-    if (this.uri.indexOf('#') < 0) {
-      return this
-    } else {
-      return new NamedNode(this.uri.split('#')[0])
-    }
-  }
-  toString () {
-    return '<' + this.uri + '>'
-  }
-
-  /* The local identifier with the document
-  */
-  id () {
-    return this.uri.split('#')[1]
-  }
-
-  /**
-   * Legacy getter and setter alias, node.uri
-   */
-  get uri () {
-    return this.value
-  }
-  set uri (uri) {
-    this.value = uri
-  }
-  static fromValue (value) {
-    if (typeof value === 'undefined' || value === null) {
-      return value
-    }
-    const isNode = value && value.termType
-    if (isNode) {
-      return value
-    }
-    return new NamedNode(value)
-  }
-}
-NamedNode.termType = 'NamedNode'
-NamedNode.prototype.classOrder = ClassOrder['NamedNode']
-NamedNode.prototype.isVar = 0
diff --git a/src/named-node.ts b/src/named-node.ts
new file mode 100644
index 000000000..944047ba0
--- /dev/null
+++ b/src/named-node.ts
@@ -0,0 +1,113 @@
+import ClassOrder from './class-order'
+import Node from './node-internal'
+import { NamedNodeTermType } from './types'
+import { termValue } from './utils/termValue'
+import { NamedNode as TFNamedNode } from './tf-types'
+import { isTerm } from './utils/terms'
+
+/**
+ * A named (IRI) RDF node
+ */
+export default class NamedNode extends Node implements TFNamedNode {
+  termType: typeof NamedNodeTermType = NamedNodeTermType
+  classOrder = ClassOrder.NamedNode
+
+  /**
+   * Create a named (IRI) RDF Node
+   * @constructor
+   * @param iri - The IRI for this node
+   */
+  constructor (iri: string) {
+    super(termValue(iri))
+
+    if (!this.value) {
+      throw new Error('Missing IRI for NamedNode')
+    }
+
+    if (!this.value.includes(':')) {
+      throw new Error('NamedNode IRI "' + iri + '" must be absolute.')
+    }
+
+    if (this.value.includes(' ')) {
+      var message = 'Error: NamedNode IRI "' + iri + '" must not contain unencoded spaces.'
+      throw new Error(message)
+    }
+  }
+
+  /**
+   * Returns an $rdf node for the containing directory, ending in slash.
+   */
+  dir (): NamedNode | null {
+     var str = this.value.split('#')[0]
+     var p = str.slice(0, -1).lastIndexOf('/')
+     var q = str.indexOf('//')
+     if ((q >= 0 && p < q + 2) || p < 0) return null
+     return new NamedNode(str.slice(0, p + 1))
+   }
+
+  /**
+   * Returns an NN for the whole web site, ending in slash.
+   * Contrast with the "origin" which does NOT have a trailing slash
+   */
+  site (): NamedNode {
+     var str = this.value.split('#')[0]
+     var p = str.indexOf('//')
+     if (p < 0) throw new Error('This URI does not have a web site part (origin)')
+     var q = str.indexOf('/', p+2)
+     if (q < 0) {
+       return new NamedNode(str.slice(0) + '/')   // Add slash to a bare origin
+     } else {
+       return new NamedNode(str.slice(0, q + 1))
+     }
+   }
+
+  /**
+   * Creates the fetchable named node for the document.
+   * Removes everything from the # anchor tag.
+   */
+  doc (): NamedNode {
+    if (this.value.indexOf('#') < 0) {
+      return this
+    } else {
+      return new NamedNode(this.value.split('#')[0])
+    }
+  }
+
+  /**
+   * Returns the URI including <brackets>
+   */
+  toString (): string {
+    return '<' + this.value + '>'
+  }
+
+  /** The local identifier with the document */
+  id (): string {
+    return this.value.split('#')[1]
+  }
+
+  /**
+   * Legacy getter and setter alias, node.uri
+   * @deprecated use [[value]]
+   */
+  get uri (): string {
+    return this.value
+  }
+
+  set uri (uri: string) {
+    this.value = uri
+  }
+
+  /**
+   * Creates a named node from the specified input value
+   * @param value - An input value
+   */
+  static fromValue (value) {
+    if (typeof value === 'undefined' || value === null) {
+      return value
+    }
+    if (isTerm(value)) {
+      return value
+    }
+    return new NamedNode(value)
+  }
+}
diff --git a/src/namespace.js b/src/namespace.js
deleted file mode 100644
index b42486d13..000000000
--- a/src/namespace.js
+++ /dev/null
@@ -1,9 +0,0 @@
-import NamedNode from './named-node'
-
-export default function Namespace (nsuri, factory) {
-  const dataFactory = factory || { namedNode: (value) => new NamedNode(value) }
-
-  return function (ln) {
-    return dataFactory.namedNode(nsuri + (ln || ''))
-  }
-}
diff --git a/src/namespace.ts b/src/namespace.ts
new file mode 100644
index 000000000..190e32ee6
--- /dev/null
+++ b/src/namespace.ts
@@ -0,0 +1,15 @@
+import RDFlibNamedNode from './named-node'
+import { RdfJsDataFactory, NamedNode } from './tf-types'
+
+/**
+ * Gets a namespace for the specified namespace's URI
+ * @param nsuri - The URI for the namespace
+ * @param [factory] - The factory for creating named nodes with
+ */
+export default function Namespace (nsuri: string, factory?: RdfJsDataFactory): (ln: string) => NamedNode {
+  const dataFactory = factory || { namedNode: (value) => new RDFlibNamedNode(value) as NamedNode }
+
+  return function (ln: string): NamedNode {
+    return dataFactory.namedNode(nsuri + (ln || ''))
+  }
+}
diff --git a/src/node-internal.js b/src/node-internal.js
deleted file mode 100644
index 2c5e63b8d..000000000
--- a/src/node-internal.js
+++ /dev/null
@@ -1,51 +0,0 @@
-'use strict'
-
-/**
- * The superclass of all RDF Statement objects, that is
- * NamedNode, Literal, BlankNode, etc.
- * @class Node
- */
-
-export default class Node {
-  substitute (bindings) {
-    console.log('@@@ node substitute' + this)
-    return this
-  }
-  compareTerm (other) {
-    if (this.classOrder < other.classOrder) {
-      return -1
-    }
-    if (this.classOrder > other.classOrder) {
-      return +1
-    }
-    if (this.value < other.value) {
-      return -1
-    }
-    if (this.value > other.value) {
-      return +1
-    }
-    return 0
-  }
-  equals (other) {
-    if (!other) {
-      return false
-    }
-    return (this.termType === other.termType) &&
-      (this.value === other.value)
-  }
-  hashString () {
-    return this.toCanonical()
-  }
-  sameTerm (other) {
-    return this.equals(other)
-  }
-  toCanonical () {
-    return this.toNT()
-  }
-  toNT () {
-    return this.toString()
-  }
-  toString () {
-    throw new Error('Node.toString() is abstract - see the subclasses instead')
-  }
-}
diff --git a/src/node-internal.ts b/src/node-internal.ts
new file mode 100644
index 000000000..2e6883cba
--- /dev/null
+++ b/src/node-internal.ts
@@ -0,0 +1,117 @@
+import { ValueType, Bindings, FromValueReturns, TermType } from './types'
+import { Term } from './tf-types'
+
+/**
+ * The superclass of all RDF Statement objects, that is
+ * NamedNode, Literal, BlankNode, etc.
+ * Should not be instantiated directly.
+ * Also called Term.
+ * @link https://rdf.js.org/data-model-spec/#term-interface
+ * @class Node
+ */
+export default abstract class Node {
+  // Specified in './node.ts' to prevent circular dependency
+  static fromValue: <T extends FromValueReturns>(value: ValueType) => T
+  // Specified in './node.ts' to prevent circular dependency
+  static toJS: (term: any) => Date | Number | string | boolean | object | Array<Date | Number | string | boolean | object>;
+
+  /** The type of node */
+  termType!: TermType;
+
+  /** The class order for this node */
+  classOrder!: number;
+
+  /** The node's value */
+  value: string;
+
+  protected constructor(value: string) {
+    this.value = value
+  }
+
+  /**
+   * Creates the substituted node for this one, according to the specified bindings
+   * @param bindings - Bindings of identifiers to nodes
+   */
+  substitute <T extends Node = Node>(bindings: Bindings): T {
+    console.log('@@@ node substitute' + this)
+    return this as unknown as T
+  }
+
+  /**
+   * Compares this node with another
+   * @see {equals} to check if two nodes are equal
+   * @param other - The other node
+   */
+  compareTerm (other: Node): number {
+    if (this.classOrder < other.classOrder) {
+      return -1
+    }
+    if (this.classOrder > other.classOrder) {
+      return +1
+    }
+    if (this.value < other.value) {
+      return -1
+    }
+    if (this.value > other.value) {
+      return +1
+    }
+    return 0
+  }
+
+  /**
+   * Compares whether the two nodes are equal
+   * @param other The other node
+   */
+  equals (other: Term): boolean {
+    if (!other) {
+      return false
+    }
+    return (this.termType === other.termType) &&
+      (this.value === other.value)
+  }
+
+  /**
+   * Creates a hash for this node
+   * @deprecated use {rdfFactory.id} instead if possible
+   */
+  hashString (): string {
+    return this.toCanonical()
+  }
+
+  /**
+   * Compares whether this node is the same as the other one
+   * @param other - Another node
+   */
+  sameTerm(other: Node): boolean {
+    return this.equals(other)
+
+  }
+
+  /**
+   * Creates a canonical string representation of this node
+   */
+  toCanonical (): string {
+    return this.toNT()
+  }
+
+  /**
+   * Creates a n-triples string representation of this node
+   */
+  toNT (): string {
+    return this.toString()
+  }
+
+  /**
+   * Creates a n-quads string representation of this node
+   */
+  toNQ (): string {
+    return this.toNT();
+  }
+
+  /**
+   * Creates a string representation of this node
+   */
+  toString (): string {
+    throw new Error('Node.toString() is abstract - see the subclasses instead')
+  }
+}
diff --git a/src/node.js b/src/node.ts
similarity index 61%
rename from src/node.js
rename to src/node.ts
index 1e16803b7..baeed84f6 100644
--- a/src/node.js
+++ b/src/node.ts
@@ -1,12 +1,10 @@
-'use strict'
-
 // This file attaches all functionality to Node
 // that would otherwise require circular dependencies.
+import { fromValue } from './collection'
 import Node from './node-internal'
-import Collection from './collection'
-import Literal from './literal'
-
-export default Node
+import Namespace from './namespace'
+import { isCollection, isLiteral } from './utils/terms'
+import { Term } from './tf-types'
 
 /**
  * Creates an RDF Node from a native javascript value.
@@ -16,30 +14,23 @@ export default Node
  * @param value {Node|Date|String|Number|Boolean|Undefined}
  * @return {Node|Collection}
  */
-Node.fromValue = function fromValue (value) {
-  if (typeof value === 'undefined' || value === null) {
-    return value
-  }
-  const isNode = value && value.termType
-  if (isNode) {  // a Node subclass or a Collection
-    return value
-  }
-  if (Array.isArray(value)) {
-    return new Collection(value)
-  }
-  return Literal.fromValue(value)
-}
+Node.fromValue = fromValue;
+
+export default Node
 
-import Namespace from './namespace'
 const ns = { xsd: Namespace('http://www.w3.org/2001/XMLSchema#') }
 
-Node.toJS = function toJS (term) {
-  if (term.elements) {
+/**
+ * Gets the javascript object equivalent to a node
+ * @param term The RDF node
+ */
+Node.toJS = function (term: Term): Term | boolean | number | Date | string | any[] {
+  if (isCollection(term)) {
     return term.elements.map(Node.toJS) // Array node (not standard RDFJS)
   }
-  if (!term.datatype) return term // Objects remain objects
+  if (!isLiteral(term)) return term
   if (term.datatype.equals(ns.xsd('boolean'))) {
-    return term.value === '1'
+    return term.value === '1' || term.value === 'true'
   }
   if (term.datatype.equals(ns.xsd('dateTime')) ||
     term.datatype.equals(ns.xsd('date'))) {
@@ -50,7 +41,6 @@ Node.toJS = function toJS (term) {
     term.datatype.equals(ns.xsd('float')) ||
     term.datatype.equals(ns.xsd('decimal'))
   ) {
-    let z = Number(term.value)
     return Number(term.value)
   }
   return term.value
diff --git a/src/parse.js b/src/parse.js
deleted file mode 100644
index ae6c47012..000000000
--- a/src/parse.js
+++ /dev/null
@@ -1,112 +0,0 @@
-import DataFactory from './data-factory'
-import jsonldParser from './jsonldparser'
-import { Parser as N3jsParser } from 'n3'  // @@ Goal: remove this dependency
-import N3Parser from './n3parser'
-import { parseRDFaDOM } from './rdfaparser'
-import RDFParser from './rdfxmlparser'
-import sparqlUpdateParser from './patch-parser'
-import * as Util from './util'
-
-/**
- * Parse a string and put the result into the graph kb.
- * Normal method is sync.
- * Unfortunately jsdonld is currently written to need to be called async.
- * Hence the mess below with executeCallback.
- */
-export default function parse (str, kb, base, contentType, callback) {
-  contentType = contentType || 'text/turtle'
-  contentType = contentType.split(';')[0]
-  try {
-    if (contentType === 'text/n3' || contentType === 'text/turtle') {
-      var p = N3Parser(kb, kb, base, base, null, null, '', null)
-      p.loadBuf(str)
-      executeCallback()
-    } else if (contentType === 'application/rdf+xml') {
-      var parser = new RDFParser(kb)
-      parser.parse(Util.parseXML(str), base, kb.sym(base))
-      executeCallback()
-    } else if (contentType === 'application/xhtml+xml') {
-      parseRDFaDOM(Util.parseXML(str, {contentType: 'application/xhtml+xml'}), kb, base)
-      executeCallback()
-    } else if (contentType === 'text/html') {
-      parseRDFaDOM(Util.parseXML(str, {contentType: 'text/html'}), kb, base)
-      executeCallback()
-    } else if (contentType === 'application/sparql-update') { // @@ we handle a subset
-      sparqlUpdateParser(str, kb, base)
-      executeCallback()
-    } else if (contentType === 'application/ld+json') {
-      jsonldParser(str, kb, base, executeCallback)
-    } else if (contentType === 'application/nquads' ||
-               contentType === 'application/n-quads') {
-      var n3Parser = new N3jsParser({ factory: DataFactory })
-      nquadCallback(null, str)
-    } else {
-      throw new Error("Don't know how to parse " + contentType + ' yet')
-    }
-  } catch (e) {
-    executeErrorCallback(e)
-  }
-
-  parse.handled = {
-    'text/n3': true,
-    'text/turtle': true,
-    'application/rdf+xml': true,
-    'application/xhtml+xml': true,
-    'text/html': true,
-    'application/sparql-update': true,
-    'application/ld+json': true,
-    'application/nquads' : true,
-    'application/n-quads' : true
-  }
-
-  function executeCallback () {
-    if (callback) {
-      callback(null, kb)
-    } else {
-      return
-    }
-  }
-
-  function executeErrorCallback (e) {
-    if (contentType !== 'application/ld+json' ||
-      contentType !== 'application/nquads' ||
-      contentType !== 'application/n-quads') {
-      if (callback) {
-        callback(e, kb)
-      } else {
-        let e2 = new Error('' + e + ' while trying to parse <' + base + '> as ' + contentType)
-        e2.cause = e
-        throw e2
-      }
-    }
-  }
-/*
-  function setJsonLdBase (doc, base) {
-    if (doc instanceof Array) {
-      return
-    }
-    if (!('@context' in doc)) {
-      doc['@context'] = {}
-    }
-    doc['@context']['@base'] = base
-  }
-*/
-  function nquadCallback (err, nquads) {
-    if (err) {
-      callback(err, kb)
-    }
-    try {
-      n3Parser.parse(nquads, tripleCallback)
-    } catch (err) {
-      callback(err, kb)
-    }
-  }
-
-  function tripleCallback (err, triple, prefixes) {
-    if (triple) {
-      kb.add(triple)
-    } else {
-      callback(err, kb)
-    }
-  }
-}
diff --git a/src/parse.ts b/src/parse.ts
new file mode 100644
index 000000000..51ea41702
--- /dev/null
+++ b/src/parse.ts
@@ -0,0 +1,137 @@
+import DataFactory from './factories/extended-term-factory'
+import jsonldParser from './jsonldparser'
+// @ts-ignore is this injected?
+import { Parser as N3jsParser } from 'n3'  // @@ Goal: remove this dependency
+import N3Parser from './n3parser'
+import { parseRDFaDOM } from './rdfaparser'
+import RDFParser from './rdfxmlparser'
+import sparqlUpdateParser from './patch-parser'
+import * as Util from './utils-js'
+import Formula from './formula'
+import { ContentType, TurtleContentType, N3ContentType, RDFXMLContentType, XHTMLContentType, HTMLContentType, SPARQLUpdateContentType, JSONLDContentType, NQuadsContentType, NQuadsAltContentType } from './types'
+import { Quad } from './tf-types'
+
+type CallbackFunc = (error: any, kb: Formula | null) => void
+
+/**
+ * Parse a string and put the result into the graph kb.
+ * Normal method is sync.
+ * Unfortunately jsdonld is currently written to need to be called async.
+ * Hence the mess below with executeCallback.
+ * @param str - The input string to parse
+ * @param kb - The store to use
+ * @param base - The base URI to use
+ * @param contentType - The MIME content type string for the input
+ * @param callback - The callback to call when the data has been loaded
+ */
+export default function parse (
+  str: string,
+  kb: Formula,
+  base: string,
+  contentType: string | ContentType,
+  callback?: CallbackFunc
+) {
+  contentType = contentType || TurtleContentType
+  contentType = contentType.split(';')[0] as ContentType
+  try {
+    if (contentType === N3ContentType || contentType === TurtleContentType) {
+      var p = N3Parser(kb, kb, base, base, null, null, '', null)
+      p.loadBuf(str)
+      executeCallback()
+    } else if (contentType === RDFXMLContentType) {
+      var parser = new RDFParser(kb)
+      parser.parse(Util.parseXML(str), base, kb.sym(base))
+      executeCallback()
+    } else if (contentType === XHTMLContentType) {
+      parseRDFaDOM(Util.parseXML(str, {contentType: XHTMLContentType}), kb, base)
+      executeCallback()
+    } else if (contentType === HTMLContentType) {
+      parseRDFaDOM(Util.parseXML(str, {contentType: HTMLContentType}), kb, base)
+      executeCallback()
+    } else if (contentType === SPARQLUpdateContentType) { // @@ we handle a subset
+      sparqlUpdateParser(str, kb, base)
+      executeCallback()
+    } else if (contentType === JSONLDContentType) {
+      jsonldParser(str, kb, base, executeCallback)
+    } else if (contentType === NQuadsContentType ||
+               contentType === NQuadsAltContentType) {
+      var n3Parser = new N3jsParser({ factory: DataFactory })
+      nquadCallback(null, str)
+    } else if (contentType === undefined) {
+      throw new Error("contentType is undefined")
+    } else {
+      throw new Error("Don't know how to parse " + contentType + ' yet')
+    }
+  } catch (e) {
+    executeErrorCallback(e)
+  }
+
+  (parse as any).handled= {
+    'text/n3': true,
+    'text/turtle': true,
+    'application/rdf+xml': true,
+    'application/xhtml+xml': true,
+    'text/html': true,
+    'application/sparql-update': true,
+    'application/ld+json': true,
+    'application/nquads' : true,
+    'application/n-quads' : true
+  }
+
+  function executeCallback () {
+    if (callback) {
+      callback(null, kb)
+    } else {
+      return
+    }
+  }
+
+  function executeErrorCallback (e: Error): void {
+    if (
+      // TODO: Always true, what is the right behavior
+      contentType !== JSONLDContentType ||
+      // @ts-ignore always true?
+      contentType !== NQuadsContentType ||
+      // @ts-ignore always true?
+      contentType !== NQuadsAltContentType
+    ) {
+      if (callback) {
+        callback(e, kb)
+      } else {
+        let e2 = new Error('' + e + ' while trying to parse <' + base + '> as ' + contentType)
+        //@ts-ignore .cause is not a default error property
+        e2.cause = e
+        throw e2
+      }
+    }
+  }
+/*
+  function setJsonLdBase (doc, base) {
+    if (doc instanceof Array) {
+      return
+    }
+    if (!('@context' in doc)) {
+      doc['@context'] = {}
+    }
+    doc['@context']['@base'] = base
+  }
+*/
+  function nquadCallback (err?: Error | null, nquads?: string): void {
+    if (err) {
+      (callback as CallbackFunc)(err, kb)
+    }
+    try {
+      n3Parser.parse(nquads, tripleCallback)
+    } catch (err) {
+      (callback as CallbackFunc)(err, kb)
+    }
+  }
+
+  function tripleCallback (err: Error, triple: Quad) {
+    if (triple) {
+      kb.add(triple.subject, triple.predicate, triple.object, triple.graph)
+    } else {
+      (callback as CallbackFunc)(err, kb)
+    }
+  }
+}
diff --git a/src/query.js b/src/query.js
index f45d60bcf..d5453374c 100644
--- a/src/query.js
+++ b/src/query.js
@@ -17,10 +17,8 @@
 // Also, users name variables and want the same name back when stuff is printed
 /* jsl:option explicit */ // Turn on JavaScriptLint variable declaration checking
 
-import {
-  default as IndexedFormula,
-  defaultGraphURI as defaultDocumentURI
-}  from './store'
+import IndexedFormula  from './store'
+import { defaultGraphURI as defaultDocumentURI } from './utils/default-graph-uri'
 import log from './log'
 import { docpart } from './uri'
 
diff --git a/src/rdfaparser.js b/src/rdfaparser.js
index ef3e4763b..1c1989742 100644
--- a/src/rdfaparser.js
+++ b/src/rdfaparser.js
@@ -14,10 +14,10 @@
 
 import BlankNode from './blank-node'
 import Literal from './literal'
-import rdf from './data-factory'
 import NamedNode from './named-node'
 import * as Uri from './uri'
-import * as Util from './util'
+import * as Util from './utils-js'
+import rdf from './factories/canonical-data-factory'
 
 if (typeof Node === 'undefined') { //  @@@@@@ Global. Interface to xmldom.
   var Node = {
diff --git a/src/serialize.js b/src/serialize.js
deleted file mode 100644
index ea48d8879..000000000
--- a/src/serialize.js
+++ /dev/null
@@ -1,70 +0,0 @@
-import * as convert from './convert'
-import Serializer from './serializer'
-
-/**
- * Serialize to the appropriate format
- * @@ Currently NQuads and JSON/LD are deal with extrelemently inefficiently
- * through mutiple conversions.
- */
-export default function serialize (target, kb, base, contentType, callback, options) {
-  base = base || target.uri
-  options = options || {}
-  contentType = contentType || 'text/turtle' // text/n3 if complex?
-  var documentString = null
-  try {
-    var sz = Serializer(kb)
-    if (options.flags) sz.setFlags(options.flags)
-    var newSts = kb.statementsMatching(undefined, undefined, undefined, target)
-    var n3String
-    sz.suggestNamespaces(kb.namespaces)
-    sz.setBase(base)
-    switch (contentType) {
-      case 'application/rdf+xml':
-        documentString = sz.statementsToXML(newSts)
-        return executeCallback(null, documentString)
-      case 'text/n3':
-      case 'application/n3': // Legacy
-        documentString = sz.statementsToN3(newSts)
-        return executeCallback(null, documentString)
-      case 'text/turtle':
-      case 'application/x-turtle': // Legacy
-        sz.setFlags('si') // Suppress = for sameAs and => for implies
-        documentString = sz.statementsToN3(newSts)
-        return executeCallback(null, documentString)
-      case 'application/n-triples':
-        sz.setFlags('deinprstux') // Suppress nice parts of N3 to make ntriples
-        documentString = sz.statementsToNTriples(newSts)
-        return executeCallback(null, documentString)
-      case 'application/ld+json':
-        sz.setFlags('deinprstux') // Use adapters to connect to incmpatible parser
-        n3String = sz.statementsToNTriples(newSts)
-        // n3String = sz.statementsToN3(newSts)
-        convert.convertToJson(n3String, callback)
-        break
-      case 'application/n-quads':
-      case 'application/nquads': // @@@ just outpout the quads? Does not work for collections
-        sz.setFlags('deinprstux q') // Suppress nice parts of N3 to make ntriples
-        documentString = sz.statementsToNTriples(newSts) // q in flag means actually quads
-        return executeCallback(null, documentString)
-        // n3String = sz.statementsToN3(newSts)
-        // documentString = convert.convertToNQuads(n3String, callback)
-        break
-      default:
-        throw new Error('Serialize: Content-type ' + contentType + ' not supported for data write.')
-    }
-  } catch (err) {
-    if (callback) {
-      return callback(err)
-    }
-    throw err // Don't hide problems from caller in sync mode
-  }
-
-  function executeCallback (err, result) {
-    if (callback) {
-      callback(err, result)
-      return
-    } else {
-      return result
-    }
-  }
-}
diff --git a/src/serialize.ts b/src/serialize.ts
new file mode 100644
index 000000000..768474ca0
--- /dev/null
+++ b/src/serialize.ts
@@ -0,0 +1,102 @@
+import * as convert from './convert'
+import Formula from './formula'
+import Serializer from './serializer'
+import {
+  ContentType,
+  JSONLDContentType,
+  N3ContentType,
+  N3LegacyContentType,
+  NQuadsAltContentType,
+  NQuadsContentType,
+  NTriplesContentType,
+  RDFXMLContentType,
+  TurtleContentType,
+  TurtleLegacyContentType,
+} from './types'
+import IndexedFormula from './store'
+import { BlankNode, NamedNode } from './tf-types'
+
+/**
+ * Serialize to the appropriate format
+ */
+export default function serialize (
+  /** The graph or nodes that should be serialized */
+  target: Formula | NamedNode | BlankNode,
+  /** The store */
+  kb?: IndexedFormula,
+  base?: unknown,
+  /**
+   * The mime type.
+   * Defaults to Turtle.
+   */
+  contentType?: string | ContentType,
+  callback?: (err: Error | undefined | null, result?: string | null) => any,
+  options?: {
+    /**
+     * A string of letters, each of which set an options
+     * e.g. `deinprstux`
+     */
+    flags: string
+  }
+): string | undefined {
+  base = base || target.value
+  const opts = options || {}
+  contentType = contentType || TurtleContentType // text/n3 if complex?
+  var documentString: string | null = null
+  try {
+    var sz = Serializer(kb)
+    if ((opts as any).flags) sz.setFlags((opts as any).flags)
+    var newSts = kb!.statementsMatching(undefined, undefined, undefined, target as NamedNode)
+    var n3String: string
+    sz.suggestNamespaces(kb!.namespaces)
+    sz.setBase(base)
+    switch (contentType) {
+      case RDFXMLContentType:
+        documentString = sz.statementsToXML(newSts)
+        return executeCallback(null, documentString)
+      case N3ContentType:
+      case N3LegacyContentType:
+        documentString = sz.statementsToN3(newSts)
+        return executeCallback(null, documentString)
+      case TurtleContentType:
+      case TurtleLegacyContentType:
+        sz.setFlags('si') // Suppress = for sameAs and => for implies
+        documentString = sz.statementsToN3(newSts)
+        return executeCallback(null, documentString)
+      case NTriplesContentType:
+        sz.setFlags('deinprstux') // Suppress nice parts of N3 to make ntriples
+        documentString = sz.statementsToNTriples(newSts)
+        return executeCallback(null, documentString)
+      case JSONLDContentType:
+        sz.setFlags('deinprstux') // Use adapters to connect to incmpatible parser
+        n3String = sz.statementsToNTriples(newSts)
+        // n3String = sz.statementsToN3(newSts)
+        convert.convertToJson(n3String, callback)
+        break
+      case NQuadsContentType:
+      case NQuadsAltContentType: // @@@ just outpout the quads? Does not work for collections
+        sz.setFlags('deinprstux q') // Suppress nice parts of N3 to make ntriples
+        documentString = sz.statementsToNTriples(newSts) // q in flag means actually quads
+        return executeCallback(null, documentString)
+        // n3String = sz.statementsToN3(newSts)
+        // documentString = convert.convertToNQuads(n3String, callback)
+        // break
+      default:
+        throw new Error('Serialize: Content-type ' + contentType + ' not supported for data write.')
+    }
+  } catch (err) {
+    if (callback) {
+      return callback(err, undefined)
+    }
+    throw err // Don't hide problems from caller in sync mode
+  }
+
+  function executeCallback (err: Error | null | undefined, result: string | null | undefined): string | undefined {
+    if (callback) {
+      callback(err, result)
+      return
+    } else {
+      return result as string
+    }
+  }
+}
diff --git a/src/serializer.js b/src/serializer.js
index 4356fb73b..003ae465e 100644
--- a/src/serializer.js
+++ b/src/serializer.js
@@ -8,8 +8,8 @@
 import NamedNode from './named-node'
 import BlankNode from './blank-node'
 import * as Uri from './uri'
-import * as Util from './util'
-import CanonicalDataFactory from './data-factory-internal'
+import * as Util from './utils-js'
+import CanonicalDataFactory from './factories/canonical-data-factory'
 import { createXSD } from './xsd'
 
 export default (function () {
diff --git a/src/statement.js b/src/statement.js
deleted file mode 100644
index 006eb7f12..000000000
--- a/src/statement.js
+++ /dev/null
@@ -1,64 +0,0 @@
-'use strict'
-import Node from './node'
-
-export default class Statement {
-  /* Construct a new statment
-  **
-  ** @param {Term} subject - The subject of the triple.  What the efact is about
-  ** @ param {Term} predciate - The relationship which is assrted between the subject and object
-  ** @param {Term} object - The thing or data value which is asserted to be related to the subject
-  ** @param {NamedNode} why - The document where thr triple is or was or will be stored on the web.
-  **
-  ** The why param is a named node of the document in which the triple when
-  ** it is stored on the web.
-  ** It is called “why” because when you have read data from varou slaces the
-  **  “why” tells you why you have the triple. (At the moment, it is just the
-  ** document, in future it could be an inference step). When you do
-  ** UpdateManager.update() then the why’s of all the statmemts must be the same,
-  ** and give the document you are patching. In future, we may have a more
-  ** powerful update() which can update more than one docment.
-  */
-  constructor (subject, predicate, object, graph) {
-    this.subject = Node.fromValue(subject)
-    this.predicate = Node.fromValue(predicate)
-    this.object = Node.fromValue(object)
-    this.why = graph  // property currently used by rdflib
-  }
-  get graph () {
-    return this.why
-  }
-  set graph (g) {
-    this.why = g
-  }
-  equals (other) {
-    return other.subject.equals(this.subject) && other.predicate.equals(this.predicate) &&
-      other.object.equals(this.object) && other.graph.equals(this.graph)
-  }
-  substitute (bindings) {
-    const y = new Statement(
-      this.subject.substitute(bindings),
-      this.predicate.substitute(bindings),
-      this.object.substitute(bindings),
-      this.why.substitute(bindings)) // 2016
-    console.log('@@@ statement substitute:' + y)
-    return y
-  }
-  toCanonical () {
-    let terms = [
-      this.subject.toCanonical(),
-      this.predicate.toCanonical(),
-      this.object.toCanonical()
-    ]
-    if (this.graph && this.graph.termType !== 'DefaultGraph') {
-        terms.push(this.graph.toCanonical())
-    }
-    return terms.join(' ') + ' .'
-  }
-  toNT () {
-    return [this.subject.toNT(), this.predicate.toNT(),
-      this.object.toNT()].join(' ') + ' .'
-  }
-  toString () {
-    return this.toNT()
-  }
-}
diff --git a/src/statement.ts b/src/statement.ts
new file mode 100644
index 000000000..fea65cd25
--- /dev/null
+++ b/src/statement.ts
@@ -0,0 +1,132 @@
+import Node from './node-internal'
+import {
+  Bindings,
+  GraphType,
+  ObjectType,
+  PredicateType,
+  SubjectType,
+  DefaultGraphTermType,
+} from './types'
+import { defaultGraphNode } from './utils/default-graph-uri'
+import { Quad_Graph, Quad_Object, Quad_Predicate, Quad, Quad_Subject, Term } from './tf-types'
+
+/** A Statement represents an RDF Triple or Quad. */
+export default class Statement implements Quad<SubjectType, PredicateType, ObjectType, GraphType> {
+  /** The subject of the triple.  What the Statement is about. */
+  subject: SubjectType
+
+  /** The relationship which is asserted between the subject and object */
+  predicate: PredicateType
+
+  /** The thing or data value which is asserted to be related to the subject */
+  object: ObjectType
+
+  /**
+   * The graph param is a named node of the document in which the triple when
+   *  it is stored on the web.
+   */
+  graph: GraphType
+
+  /**
+   * Construct a new statement
+   *
+   * @param subject - The subject of the triple.  What the fact is about
+   * @param predicate - The relationship which is asserted between the subject and object
+   * @param object - The thing or data value which is asserted to be related to the subject
+   * @param {NamedNode} graph - The document where the triple is or was or will be stored on the web.
+   *
+   * The graph param is a named node of the document in which the triple when it is stored
+   *  on the web. It exists because when you have read data from various places in the web,
+   *  the “graph” tells you _why_ you have the triple. (At the moment, it is just the
+   *  document, in future it could be an inference step)
+   *
+   * When you do UpdateManager.update() then the graph’s of all the statements must be the same,
+   *  and give the document you are patching. In future, we may have a more
+   *  powerful update() which can update more than one document.
+   */
+  constructor (
+    subject: Quad_Subject | Term,
+    predicate: Quad_Predicate | Term,
+    object: Quad_Object | Term,
+    graph?: Quad_Graph | Term,
+  ) {
+    this.subject = Node.fromValue(subject)
+    this.predicate = Node.fromValue(predicate)
+    this.object = Node.fromValue(object)
+    this.graph = graph == undefined ? defaultGraphNode : Node.fromValue(graph) // property currently used by rdflib
+  }
+
+  /** @deprecated use {graph} instead */
+  get why () {
+    return this.graph
+  }
+
+  set why (g) {
+    this.graph = g
+  }
+
+  /**
+   * Checks whether two statements are the same
+   * @param other - The other statement
+   */
+  equals (other: Quad): boolean {
+    return (
+      other.subject.equals(this.subject) &&
+      other.predicate.equals(this.predicate) &&
+      other.object.equals(this.object) &&
+      other.graph.equals(this.graph)
+    )
+  }
+
+  /**
+   * Creates a statement with the bindings substituted
+   * @param bindings The bindings
+   */
+  substitute (bindings: Bindings): Statement {
+    const y = new Statement(
+      this.subject.substitute(bindings),
+      this.predicate.substitute(bindings),
+      this.object.substitute(bindings),
+      this.graph.substitute<GraphType>(bindings),
+    ) // 2016
+    console.log('@@@ statement substitute:' + y)
+    return y
+  }
+
+  /** Creates a canonical string representation of this statement. */
+  toCanonical (): string {
+    let terms = [
+      this.subject.toCanonical(),
+      this.predicate.toCanonical(),
+      this.object.toCanonical()
+    ]
+    if (this.graph && this.graph.termType !== DefaultGraphTermType) {
+        terms.push(this.graph.toCanonical())
+    }
+    return terms.join(' ') + ' .'
+  }
+
+  /** Creates a n-triples string representation of this statement */
+  toNT (): string {
+    return [
+      this.subject.toNT(),
+      this.predicate.toNT(),
+      this.object.toNT(),
+    ].join(' ') + ' .'
+  }
+
+  /** Creates a n-quads string representation of this statement */
+  toNQ (): string {
+    return [
+      this.subject.toNT(),
+      this.predicate.toNT(),
+      this.object.toNT(),
+      this.graph.toNT(),
+    ].join(' ') + ' .'
+  }
+
+  /** Creates a string representation of this statement */
+  toString (): string {
+    return this.toNT()
+  }
+}
diff --git a/src/store.js b/src/store.ts
similarity index 58%
rename from src/store.js
rename to src/store.ts
index acbc2a6e5..d3c57247a 100644
--- a/src/store.js
+++ b/src/store.ts
@@ -10,6 +10,7 @@
  *
  *  2005-10 Written Tim Berners-Lee
  *  2007    Changed so as not to munge statements from documents when smushing
+ *  2019    Converted to typescript
  *
  *
 */
@@ -17,22 +18,54 @@
 /** @module store */
 
 import ClassOrder from './class-order'
-import { defaultGraphURI } from './data-factory-internal'
-import DataFactory from './data-factory'
-import Formula from './formula'
-import { ArrayIndexOf, isStatement, isStore, RDFArrayRemove } from './util'
-import Statement from './statement'
+import { defaultGraphURI } from './factories/canonical-data-factory'
+import Formula, { FormulaOpts } from './formula'
+import { ArrayIndexOf } from './utils'
+import { RDFArrayRemove } from './utils-js'
+import {
+  isRDFlibObject,
+  isStore,
+  isGraph,
+  isPredicate,
+  isQuad,
+  isSubject
+} from './utils/terms'
 import Node from './node'
 import Variable from './variable'
 import { Query, indexedFormulaQuery } from './query'
+import UpdateManager from './update-manager'
+import {
+  Bindings,
+} from './types'
+import Statement from './statement'
+import { Indexable } from './factories/factory-types'
+import NamedNode from './named-node'
+import Fetcher from './fetcher'
+import {
+  BlankNode,
+  Quad_Graph,
+  NamedNode as TFNamedNode,
+  Quad_Object,
+  Quad_Predicate,
+  Quad,
+  Quad_Subject,
+  Term
+} from './tf-types'
 
 const owlNamespaceURI = 'http://www.w3.org/2002/07/owl#'
 
+type FeaturesType = Array<('sameAs' | 'InverseFunctionalProperty' | 'FunctionalProperty')> | undefined
+
 export { defaultGraphURI }
 // var link_ns = 'http://www.w3.org/2007/ont/link#'
 
 // Handle Functional Property
-function handleFP (formula, subj, pred, obj) {
+function handleFP (
+  formula: IndexedFormula,
+  subj: Quad_Subject,
+  pred: Quad_Predicate,
+  obj: Quad_Object
+): boolean {
   var o1 = formula.any(subj, pred, undefined)
   if (!o1) {
     return false // First time with this value
@@ -43,7 +76,12 @@ function handleFP (formula, subj, pred, obj) {
 } // handleFP
 
 // Handle Inverse Functional Property
-function handleIFP (formula, subj, pred, obj) {
+function handleIFP (
+  formula: IndexedFormula,
+  subj: Quad_Subject,
+  pred: Quad_Predicate,
+  obj: Quad_Object
+): boolean {
   var s1 = formula.any(undefined, pred, obj)
   if (!s1) {
     return false // First time with this value
@@ -53,9 +91,16 @@ function handleIFP (formula, subj, pred, obj) {
   return true
 } // handleIFP
 
-function handleRDFType (formula, subj, pred, obj, why) {
+function handleRDFType (
+  formula: IndexedFormula,
+  subj: Quad_Subject,
+  pred: Quad_Predicate,
+  obj: Quad_Object,
+  why: Quad_Graph
+) {
+  //@ts-ignore this method does not seem to exist in this library
   if (formula.typeCallback) {
-    formula.typeCallback(formula, obj, why)
+    (formula as any).typeCallback(formula, obj, why)
   }
 
   var x = formula.classActions[formula.id(obj)]
@@ -67,32 +112,76 @@ function handleRDFType (formula, subj, pred, obj, why) {
   }
   return done // statement given is not needed if true
 }
+
 /**
  * Indexed Formula aka Store
  */
 export default class IndexedFormula extends Formula { // IN future - allow pass array of statements to constructor
   /**
-   * @constructor
-   * @param {Array<String>} features - What sort of autmatic processing to do? Array of string
-   * @param {Boolean} features.sameAs - Smush together A and B nodes whenever { A sameAs B }
+   * An UpdateManager initialised to this store
+   */
+  updater?: UpdateManager
+
+  /**
+   * Dictionary of namespace prefixes
+   */
+  namespaces: {[key: string]: string}
+
+  /** Map of iri predicates to functions to call when adding { s type X } */
+  classActions: { [k: string]: Function[] }
+  /** Map of iri predicates to functions to call when getting statement with {s X o} */
+  propertyActions: { [k: string]: Function[] }
+  /** Redirect to lexically smaller equivalent symbol */
+  redirections: any[]
+  /** Reverse mapping to redirection: aliases for this */
+  aliases: any[]
+  /** Redirections we got from HTTP */
+  HTTPRedirects: Quad[]
+  /** Array of statements with this X as subject */
+  subjectIndex: Quad[]
+  /** Array of statements with this X as predicate */
+  predicateIndex: Quad[]
+  /** Array of statements with this X as object */
+  objectIndex: Quad[]
+  /** Array of statements with X as provenance */
+  whyIndex: Quad[]
+  index: [
+    Quad[],
+    Quad[],
+    Quad[],
+    Quad[]
+  ]
+  features: FeaturesType
+  static handleRDFType: Function
+  _universalVariables?: TFNamedNode[]
+  _existentialVariables?: BlankNode[]
+
+  /** Function to remove quads from the store arrays with */
+  private rdfArrayRemove: (arr: Quad[], q: Quad) => void
+  /** Callbacks which are triggered after a statement has been added to the store */
+  private dataCallbacks?: Array<(q: Quad) => void>
+
+  /**
+   * Creates a new formula
+   * @param features - What sort of autmatic processing to do? Array of string
+   * @param features.sameAs - Smush together A and B nodes whenever { A sameAs B }
    * @param opts
-   * @param {DataFactory} [opts.rdfFactory] - The data factory that should be used by the store
-   * @param {DataFactory} [opts.rdfArrayRemove] - Function which removes statements from the store
-   * @param {DataFactory} [opts.dataCallback] - Callback when a statement is added to the store, will not trigger when adding duplicates
+   * @param [opts.rdfFactory] - The data factory that should be used by the store
+   * @param [opts.rdfArrayRemove] - Function which removes statements from the store
+   * @param [opts.dataCallback] - Callback when a statement is added to the store, will not trigger when adding duplicates
    */
-  constructor (features, opts = {}) {
+  constructor (features?: FeaturesType, opts: FormulaOpts = {}) {
     super(undefined, undefined, undefined, undefined, opts)
 
-    this.propertyActions = [] // Array of functions to call when getting statement with {s X o}
-    // maps <uri> to [f(F,s,p,o),...]
-    this.classActions = [] // Array of functions to call when adding { s type X }
-    this.redirections = [] // redirect to lexically smaller equivalent symbol
-    this.aliases = [] // reverse mapping to redirection: aliases for this
-    this.HTTPRedirects = [] // redirections we got from HTTP
-    this.subjectIndex = [] // Array of statements with this X as subject
-    this.predicateIndex = [] // Array of statements with this X as subject
-    this.objectIndex = [] // Array of statements with this X as object
-    this.whyIndex = [] // Array of statements with X as provenance
+    this.propertyActions = {}
+    this.classActions = {}
+    this.redirections = []
+    this.aliases = []
+    this.HTTPRedirects = []
+    this.subjectIndex = []
+    this.predicateIndex = []
+    this.objectIndex = []
+    this.whyIndex = []
     this.index = [
       this.subjectIndex,
       this.predicateIndex,
@@ -113,41 +202,68 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     this.initPropertyActions(this.features)
   }
 
-  static get defaultGraphURI () {
+  /**
+   * Gets the URI of the default graph
+   */
+  static get defaultGraphURI(): string {
     return defaultGraphURI
   }
 
-  substitute (bindings) {
-    var statementsCopy = this.statements.map(function (ea) {
-      return ea.substitute(bindings)
+  /**
+   * Gets this graph with the bindings substituted
+   * @param bindings The bindings
+   */
+  //@ts-ignore different from signature in Formula
+  substitute(bindings: Bindings): IndexedFormula {
+    var statementsCopy = this.statements.map(function (ea: Quad) {
+      return (ea as Statement).substitute(bindings)
     })
     var y = new IndexedFormula()
     y.add(statementsCopy)
     return y
   }
 
-  addDataCallback(cb) {
+  /**
+   * Add a callback which will be triggered after a statement has been added to the store.
+   * @param cb
+   */
+  addDataCallback(cb: (q: Quad) => void): void {
     if (!this.dataCallbacks) {
       this.dataCallbacks = []
     }
     this.dataCallbacks.push(cb)
   }
 
-  applyPatch (patch, target, patchCallback) { // patchCallback(err)
+  /**
+   * Apply a set of statements to be deleted and to be inserted
+   *
+   * @param patch - The set of statements to be deleted and to be inserted
+   * @param target - The name of the document to patch
+   * @param patchCallback - Callback to be called when patching is complete
+   */
+  applyPatch(
+    patch: {
+        delete?: ReadonlyArray<Statement>,
+        patch?: ReadonlyArray<Statement>,
+        where?: any
+    },
+    target: TFNamedNode,
+    patchCallback: (errorString?: string) => void
+  ): void {
     var targetKB = this
     var ds
-    var binding = null
+    var binding: Bindings | null = null
 
-    function doPatch (onDonePatch) {
+    function doPatch (onDonePatch: (errorString?: string) => void) {
       if (patch['delete']) {
         ds = patch['delete']
         // console.log(bindingDebug(binding))
         // console.log('ds before substitute: ' + ds)
         if (binding) ds = ds.substitute(binding)
         // console.log('applyPatch: delete: ' + ds)
-        ds = ds.statements
-        var bad = []
-        var ds2 = ds.map(function (st) { // Find the actual statemnts in the store
+        ds = ds.statements as Statement[]
+        var bad: Quad[] = []
+        var ds2 = ds.map(function (st: Quad) { // Find the actual statemnts in the store
           var sts = targetKB.statementsMatching(st.subject, st.predicate, st.object, target)
           if (sts.length === 0) {
             // log.info("NOT FOUND deletable " + st)
@@ -163,7 +279,7 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
           // console.log('despite ' + targetKB.statementsMatching(bad[0].subject, bad[0].predicate)[0])
           return patchCallback('Could not find to delete: ' + bad.join('\n or '))
         }
-        ds2.map(function (st) {
+        ds2.map(function (st: Quad) {
           targetKB.remove(st)
         })
       }
@@ -172,9 +288,9 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
         ds = patch['insert']
         if (binding) ds = ds.substitute(binding)
         ds = ds.statements
-        ds.map(function (st) {
-          st.why = target
-          targetKB.add(st.subject, st.predicate, st.object, st.why)
+        ds.map(function (st: Quad) {
+          st.graph = target
+          targetKB.add(st.subject, st.predicate, st.object, st.graph)
         })
       }
       onDonePatch()
@@ -184,13 +300,16 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
       var query = new Query('patch')
       query.pat = patch.where
       query.pat.statements.map(function (st) {
-        st.why = target
+        st.graph = target
       })
+      //@ts-ignore TODO: add sync property to Query when converting Query to typescript
       query.sync = true
 
-      var bindingsFound = []
+      var bindingsFound: Bindings[] = []
 
-      targetKB.query(query, function onBinding (binding) {
+      targetKB.query(
+        query,
+        function onBinding (binding) {
         bindingsFound.push(binding)
         // console.log('   got a binding: ' + bindingDebug(binding))
       },
@@ -210,13 +329,21 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     }
   }
 
-  declareExistential (x) {
+  /**
+   * N3 allows for declaring blank nodes, this function enables that support
+   *
+   * @param x The blank node to be declared, supported in N3
+   */
+  declareExistential(x: BlankNode): BlankNode {
     if (!this._existentialVariables) this._existentialVariables = []
     this._existentialVariables.push(x)
     return x
   }
 
-  initPropertyActions (features) {
+  /**
+   * @param features
+   */
+  initPropertyActions(features: FeaturesType) {
     // If the predicate is #type, use handleRDFType to create a typeCallback on the object
     this.propertyActions[this.rdfFactory.id(this.rdfFactory.namedNode('http://www.w3.org/1999/02/22-rdf-syntax-ns#type'))] =
       [ handleRDFType ]
@@ -249,48 +376,72 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   }
 
   /** @deprecated Use {add} instead */
-  addStatement (st) {
-    return this.add(st.subject, st.predicate, st.object, st.graph)
+  addStatement (st: Quad): number {
+    this.add(st.subject, st.predicate, st.object, st.graph)
+    return this.statements.length
   }
 
   /**
    * Adds a triple (quad) to the store.
    *
-   * @param {Term} subject - The thing about which the fact a relationship is asserted
-   * @param {namedNode} predicate - The relationship which is asserted
-   * @param {Term} object - The object of the relationship, e.g. another thing or avalue
-   * @param {namedNode} why - The document in which the triple (S,P,O) was or will be stored on the web
-   * @returns {Statement} The statement added to the store
+   * @param subj - The thing about which the fact a relationship is asserted.
+   *        Also accepts a statement or an array of Statements.
+   * @param pred - The relationship which is asserted
+   * @param obj - The object of the relationship, e.g. another thing or avalue
+   * @param why - The document in which the triple (S,P,O) was or will be stored on the web
+   * @returns The statement added to the store, or the store
    */
-  add (subj, pred, obj, why) {
-    var i
+  // @ts-ignore differs from signature in Formula
+  add (
+    subj: Quad_Subject | Quad | Quad[] | Statement | Statement[],
+    pred?: Quad_Predicate,
+    obj?: Term,
+    why?: Quad_Graph
+  ): Quad | null | IndexedFormula {
+    var i: number
     if (arguments.length === 1) {
       if (subj instanceof Array) {
         for (i = 0; i < subj.length; i++) {
           this.add(subj[i])
         }
-      } else if (isStatement(subj)) {
-        this.add(subj.subject, subj.predicate, subj.object, subj.why)
+      } else if (isQuad(subj)) {
+        this.add(subj.subject, subj.predicate, subj.object, subj.graph)
       } else if (isStore(subj)) {
         this.add(subj.statements)
       }
       return this
     }
-    var actions
-    var st
+    var actions: Function[]
+    var st: Quad
     if (!why) {
       // system generated
-      why = this.fetcher ? this.fetcher.appNode : this.defaultGraph()
+      why = this.fetcher ? this.fetcher.appNode : this.rdfFactory.defaultGraph()
+    }
+    if (typeof subj == 'string') {
+      subj = this.rdfFactory.namedNode(subj)
     }
-    subj = Node.fromValue(subj)
     pred = Node.fromValue(pred)
     obj = Node.fromValue(obj)
     why = Node.fromValue(why)
+    if (!isSubject(subj)) {
+      throw new Error('Subject is not a subject type')
+    }
+    if (!isPredicate(pred)) {
+      throw new Error(`Predicate ${pred} is not a predicate type`)
+    }
+    if (!isRDFlibObject(obj)) {
+      throw new Error(`Object ${obj} is not an object type`)
+    }
+    if (!isGraph(why)) {
+      throw new Error("Why is not a graph type")
+    }
+    //@ts-ignore This is not used internally
     if (this.predicateCallback) {
+      //@ts-ignore This is not used internally
       this.predicateCallback(this, pred, why)
     }
     // Action return true if the statement does not need to be added
-    var predHash = this.id(this.canon(pred))
+    var predHash = this.id(this.canon(pred!))
     actions = this.propertyActions[predHash] // Predicate hash
     var done = false
     if (actions) {
@@ -313,6 +464,7 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
       this.id(this.canon(obj)),
       this.id(this.canon(why))
     ]
+    // @ts-ignore this will fail if you pass a collection and the factory does not allow Collections
     st = this.rdfFactory.quad(subj, pred, obj, why)
     for (i = 0; i < 4; i++) {
       var ix = this.index[i]
@@ -337,8 +489,9 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
 
   /**
    * Returns the symbol with canonical URI as smushed
+   * @param term - An RDF node
    */
-  canon (term) {
+  canon(term: Term): Term {
     if (!term) {
       return term
     }
@@ -349,12 +502,17 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     return y
   }
 
-  check () {
+
+  /**
+   * Checks this formula for consistency
+   */
+  check(): void {
     this.checkStatementList(this.statements)
     for (var p = 0; p < 4; p++) {
       var ix = this.index[p]
       for (var key in ix) {
         if (ix.hasOwnProperty(key)) {
+          // @ts-ignore should this pass an array or a single statement? checkStateMentsList expects an array.
           this.checkStatementList(ix[key], p)
         }
       }
@@ -362,22 +520,29 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   }
 
   /**
-   * Self-consistency checking for diagnostis only
-   * Is each statement properly indexed?
+   * Checks a list of statements for consistency
+   * @param sts - The list of statements to check
+   * @param from - An index with the array ['subject', 'predicate', 'object', 'why']
    */
-  checkStatementList (sts, from) {
+  checkStatementList(
+    sts: ReadonlyArray<Quad>,
+    from?: number
+  ): boolean | void {
+    if (from === undefined) {
+      from = 0
+    }
     var names = ['subject', 'predicate', 'object', 'why']
     var origin = ' found in ' + names[from] + ' index.'
-    var st
+    var st: Quad
     for (var j = 0; j < sts.length; j++) {
       st = sts[j]
-      var term = [ st.subject, st.predicate, st.object, st.why ]
-      var arrayContains = function (a, x) {
+      var term = [ st.subject, st.predicate, st.object, st.graph ]
+      var arrayContains = function (a: Array<any>, x: Quad) {
         for (var i = 0; i < a.length; i++) {
           if (a[i].subject.equals(x.subject) &&
             a[i].predicate.equals(x.predicate) &&
             a[i].object.equals(x.object) &&
-            a[i].why.equals(x.why)) {
+            a[i].why.equals(x.graph)) {
             return true
           }
         }
@@ -394,21 +559,24 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
         }
       }
       if (!arrayContains(this.statements, st)) {
-        throw new Error('Statement list does not statement ' + st + '@' + st.why + origin)
+        throw new Error('Statement list does not statement ' + st + '@' + st.graph + origin)
       }
     }
   }
 
-  close () {
+  /**
+   * Closes this formula (and return it)
+   */
+  close(): IndexedFormula {
     return this
   }
 
-  compareTerm(u1, u2) {
+  // @ts-ignore incompatible with Forumala.compareTerm
+  compareTerm(u1: Term, u2: Term): number {
     // Keep compatibility with downstream classOrder changes
     if (Object.prototype.hasOwnProperty.call(u1, "compareTerm")) {
-      return u1.compareTerm(u2)
+      return (u1 as Node).compareTerm(u2 as Node)
     }
-
     if (ClassOrder[u1.termType] < ClassOrder[u2.termType]) {
       return -1
     }
@@ -424,13 +592,19 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     return 0
   }
 
+
   /**
-   * replaces @template with @target and add appropriate triples (no triple
-   * removed)
-   * one-direction replication
-   * @method copyTo
+   * replaces @template with @target and add appropriate triples
+   * removes no triples by default and is a one-direction replication
+   * @param template node to copy
+   * @param target node to copy to
+   * @param flags Whether or not to do a two-directional copy and/or delete triples
    */
-  copyTo (template, target, flags) {
+  copyTo(
+    template: Quad_Subject,
+    target: Quad_Subject,
+    flags?: Array<('two-direction' | 'delete')>
+  ): void {
     if (!flags) flags = []
     var statList = this.statementsMatching(template)
     if (ArrayIndexOf(flags, 'two-direction') !== -1) {
@@ -444,7 +618,9 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
           break
         case 'Literal':
         case 'BlankNode':
+        // @ts-ignore Collections can appear here
         case 'Collection':
+          // @ts-ignore Possible bug: copy is not available on Collections
           this.add(target, st.predicate, st.object.copy(this))
       }
       if (ArrayIndexOf(flags, 'delete') !== -1) {
@@ -454,15 +630,17 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   }
 
   /**
-   * simplify graph in store when we realize two identifiers are equivalent
+   * Simplify graph in store when we realize two identifiers are equivalent
    * We replace the bigger with the smaller.
+   * @param u1in The first node
+   * @param u2in The second node
    */
-  equate (u1, u2) {
+  equate(u1in: Term, u2in : Term): boolean {
     // log.warn("Equating "+u1+" and "+u2); // @@
     // @@JAMBO Must canonicalize the uris to prevent errors from a=b=c
     // 03-21-2010
-    u1 = this.canon(u1)
-    u2 = this.canon(u2)
+    const u1 = this.canon(u1in) as Quad_Subject
+    const u2 = this.canon(u2in) as Quad_Subject
     var d = this.compareTerm(u1, u2)
     if (!d) {
       return true // No information in {a = a}
@@ -476,7 +654,13 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     }
   }
 
-  formula (features) {
+  /**
+   * Creates a new empty indexed formula
+   * Only applicable for IndexedFormula, but TypeScript won't allow a subclass to override a property
+   * @param features The list of features
+   */
+  //@ts-ignore Incompatible signature with Formula.formula
+  formula(features: FeaturesType): IndexedFormula {
     return new IndexedFormula(features)
   }
 
@@ -490,21 +674,25 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
    *    ```
    * @returns {Number}
    */
-  get length () {
+  get length (): number {
     return this.statements.length
   }
 
   /**
    * Returns any quads matching the given arguments.
-   * Standard RDFJS Taskforce method for Source objects, implemented as an
+   * Standard RDFJS spec method for Source objects, implemented as an
    * alias to `statementsMatching()`
-   * @method match
-   * @param subject {Node|String|Object}
-   * @param predicate {Node|String|Object}
-   * @param object {Node|String|Object}
-   * @param graph {NamedNode|String}
+   * @param subject The subject
+   * @param predicate The predicate
+   * @param object The object
+   * @param graph The graph that contains the statement
    */
-  match (subject, predicate, object, graph) {
+  match(
+    subject?: Quad_Subject | null,
+    predicate?: Quad_Predicate | null,
+    object?: Quad_Object | null,
+    graph?: Quad_Graph | null
+  ): Quad[] {
     return this.statementsMatching(
       Node.fromValue(subject),
       Node.fromValue(predicate),
@@ -515,22 +703,40 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
 
   /**
    * Find out whether a given URI is used as symbol in the formula
+   * @param uri The URI to look for
    */
-  mentionsURI (uri) {
+  mentionsURI(uri: string): boolean {
     var hash = '<' + uri + '>'
     return (!!this.subjectIndex[hash] ||
     !!this.objectIndex[hash] ||
     !!this.predicateIndex[hash])
   }
 
-  // Existentials are BNodes - something exists without naming
-  newExistential (uri) {
+  /**
+   * Existentials are BNodes - something exists without naming
+   * @param uri An URI
+   */
+  newExistential(uri: string): Term {
     if (!uri) return this.bnode()
     var x = this.sym(uri)
+    // @ts-ignore x should be blanknode, but is namedNode.
     return this.declareExistential(x)
   }
 
-  newPropertyAction (pred, action) {
+  /**
+   * Adds a new property action
+   * @param pred the predicate that the function should be triggered on
+   * @param action the function that should trigger
+   */
+  newPropertyAction(
+    pred: Quad_Predicate,
+    action: (
+      store: IndexedFormula,
+      subject: Quad_Subject,
+      predicate: Quad_Predicate,
+      object: Quad_Object
+    ) => boolean
+  ): boolean {
     // log.debug("newPropertyAction:  "+pred)
     var hash = this.id(pred)
     if (!this.propertyActions[hash]) {
@@ -546,8 +752,12 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     return done
   }
 
-  // Universals are Variables
-  newUniversal (uri) {
+  /**
+   * Creates a new universal node
+   * Universals are Variables
+   * @param uri An URI
+   */
+  newUniversal(uri: string): TFNamedNode {
     var x = this.sym(uri)
     if (!this._universalVariables) this._universalVariables = []
     this._universalVariables.push(x)
@@ -555,39 +765,55 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   }
 
   // convenience function used by N3 parser
-  variable (name) {
+  // @ts-ignore does not correctly extends from Formula
+  variable (name: string) {
     return new Variable(name)
   }
 
   /**
    * Find an unused id for a file being edited: return a symbol
    * (Note: Slow iff a lot of them -- could be O(log(k)) )
+   * @param doc A document named node
    */
-  nextSymbol (doc) {
+  nextSymbol(doc: TFNamedNode): TFNamedNode {
     for (var i = 0; ;i++) {
-      var uri = doc.uri + '#n' + i
+      var uri = doc.value + '#n' + i
       if (!this.mentionsURI(uri)) return this.sym(uri)
     }
   }
 
-  query (myQuery, callback, dummy, onDone) {
+  /**
+   * Query this store asynchronously, return bindings in callback
+   *
+   * @param myQuery The query to be run
+   * @param callback Function to call when bindings
+   * @param dummy OBSOLETE - do not use this
+   * @param onDone OBSOLETE - do not use this
+   */
+  query(
+    myQuery: Query,
+    callback: (bindings: Bindings) => void,
+    dummy?: Fetcher | null,
+    onDone?: () => void
+  ): void {
     return indexedFormulaQuery.call(this, myQuery, callback, dummy, onDone)
   }
 
-/** Query this store synchhronously and return bindings
- *
- * @param myQuery {Query} - the query object
- * @returns {Array<Bindings>}
- */
-  querySync (myQuery) {
-    function saveBinginds (bindings) {
+  /**
+   * Query this store synchronously and return bindings
+   *
+   * @param myQuery The query to be run
+   */
+  querySync(myQuery: Query): any[] {
+    var results: Bindings[] = []
+    function saveBinginds (bindings: Bindings) {
       results.push(bindings)
     }
     function onDone () {
       done = true
     }
-    var results = []
     var done = false
+    // @ts-ignore TODO: Add .sync to Query
     myQuery.sync = true
 
     indexedFormulaQuery.call(this, myQuery, saveBinginds, null, onDone)
@@ -598,9 +824,10 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   }
 
   /**
-   * Finds a statement object and removes it
+   * Removes one or multiple statement(s) from this formula
+   * @param st - A Statement or array of Statements to remove
    */
-  remove (st) {
+  remove(st: Quad | Quad[]): IndexedFormula {
     if (st instanceof Array) {
       for (var i = 0; i < st.length; i++) {
         this.remove(st[i])
@@ -610,8 +837,7 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     if (isStore(st)) {
       return this.remove(st.statements)
     }
-    var sts = this.statementsMatching(st.subject, st.predicate, st.object,
-      st.why)
+    var sts = this.statementsMatching(st.subject, st.predicate, st.object, st.graph)
     if (!sts.length) {
       throw new Error('Statement to be removed is not on store: ' + st)
     }
@@ -621,9 +847,10 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
 
   /**
    * Removes all statemnts in a doc
+   * @param doc - The document / graph
    */
-  removeDocument (doc) {
-    var sts = this.statementsMatching(undefined, undefined, undefined, doc).slice() // Take a copy as this is the actual index
+  removeDocument(doc: Quad_Graph): IndexedFormula {
+    var sts: Quad[] = this.statementsMatching(undefined, undefined, undefined, doc).slice() // Take a copy as this is the actual index
     for (var i = 0; i < sts.length; i++) {
       this.removeStatement(sts[i])
     }
@@ -631,37 +858,61 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   }
 
   /**
-   * remove all statements matching args (within limit) *
+   * Remove all statements matching args (within limit) *
+   * @param subj The subject
+   * @param pred The predicate
+   * @param obj The object
+   * @param why The graph that contains the statement
+   * @param limit The number of statements to remove
    */
-  removeMany (subj, pred, obj, why, limit) {
+  removeMany(
+    subj?: Quad_Subject | null,
+    pred?: Quad_Predicate | null,
+    obj?: Quad_Object | null,
+    why?: Quad_Graph | null,
+    limit?: number
+  ): void {
     // log.debug("entering removeMany w/ subj,pred,obj,why,limit = " + subj +", "+ pred+", " + obj+", " + why+", " + limit)
     var sts = this.statementsMatching(subj, pred, obj, why, false)
     // This is a subtle bug that occcured in updateCenter.js too.
     // The fact is, this.statementsMatching returns this.whyIndex instead of a copy of it
     // but for perfromance consideration, it's better to just do that
     // so make a copy here.
-    var statements = []
+    var statements: Quad[] = []
     for (var i = 0; i < sts.length; i++) statements.push(sts[i])
     if (limit) statements = statements.slice(0, limit)
     for (i = 0; i < statements.length; i++) this.remove(statements[i])
   }
 
-  removeMatches (subject, predicate, object, why) {
-    this.removeStatements(this.statementsMatching(subject, predicate, object,
-      why))
+  /**
+   * Remove all matching statements
+   * @param subject The subject
+   * @param predicate The predicate
+   * @param object The object
+   * @param graph The graph that contains the statement
+   */
+  removeMatches(
+    subject?: Quad_Subject | null,
+    predicate?: Quad_Predicate | null,
+    object?: Quad_Object | null,
+    graph?: Quad_Graph | null
+  ): IndexedFormula {
+    this.removeStatements(
+      this.statementsMatching(subject, predicate, object, graph)
+    )
     return this
   }
 
   /**
    * Remove a particular statement object from the store
    *
-   * st    a statement which is already in the store and indexed.
-   *      Make sure you only use this for these.
-   *    Otherwise, you should use remove() above.
+   * @param st - a statement which is already in the store and indexed.
+   *        Make sure you only use this for these.
+   *        Otherwise, you should use remove() above.
    */
-  removeStatement (st) {
+  removeStatement(st: Quad): IndexedFormula {
     // log.debug("entering remove w/ st=" + st)
-    var term = [ st.subject, st.predicate, st.object, st.why ]
+    var term = [ st.subject, st.predicate, st.object, st.graph ]
     for (var p = 0; p < 4; p++) {
       var c = this.canon(term[p])
       var h = this.id(c)
@@ -675,7 +926,11 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     return this
   }
 
-  removeStatements (sts) {
+  /**
+   * Removes statements
+   * @param sts The statements to remove
+   */
+  removeStatements(sts: ReadonlyArray<Quad>): IndexedFormula {
     for (var i = 0; i < sts.length; i++) {
       this.remove(sts[i])
     }
@@ -685,7 +940,7 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   /**
    * Replace big with small, obsoleted with obsoleting.
    */
-  replaceWith (big, small) {
+  replaceWith (big: Quad_Subject, small: Quad_Subject): boolean {
     // log.debug("Replacing "+big+" with "+small) // this.id(@@
     var oldhash = this.id(big)
     var newhash = this.id(small)
@@ -707,7 +962,7 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
       moveIndex(this.index[i])
     }
     this.redirections[oldhash] = small
-    if (big.uri) {
+    if (big.value) {
       // @@JAMBO: must update redirections,aliases from sub-items, too.
       if (!this.aliases[newhash]) {
         this.aliases[newhash] = []
@@ -719,7 +974,7 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
           this.aliases[newhash].push(this.aliases[oldhash][i])
         }
       }
-      this.add(small, this.sym('http://www.w3.org/2007/ont/link#uri'), big.uri)
+      this.add(small, this.sym('http://www.w3.org/2007/ont/link#uri'), big)
       // If two things are equal, and one is requested, we should request the other.
       if (this.fetcher) {
         this.fetcher.nowKnownAs(big, small)
@@ -733,8 +988,9 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
 
   /**
    * Return all equivalent URIs by which this is known
+   * @param x A named node
    */
-  allAliases (x) {
+  allAliases(x: NamedNode): NamedNode[] {
     var a = this.aliases[this.id(this.canon(x))] || []
     a.push(this.canon(x))
     return a
@@ -742,8 +998,10 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
 
   /**
    * Compare by canonical URI as smushed
+   * @param x A named node
+   * @param y Another named node
    */
-  sameThings (x, y) {
+  sameThings(x: NamedNode, y: NamedNode): boolean {
     if (x.equals(y)) {
       return true
     }
@@ -753,10 +1011,10 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     var y1 = this.canon(y)
     //    alert('y1='+y1); //@@
     if (!y1) return false
-    return (x1.uri === y1.uri)
+    return (x1.value === y1.value)
   }
 
-  setPrefixForURI (prefix, nsuri) {
+  setPrefixForURI (prefix: string, nsuri: string): void {
     // TODO: This is a hack for our own issues, which ought to be fixed
     // post-release
     // See http://dig.csail.mit.edu/cgi-bin/roundup.cgi/$rdf/issue227
@@ -772,21 +1030,27 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   /** Search the Store
    *
    * ALL CONVENIENCE LOOKUP FUNCTIONS RELY ON THIS!
-   * @param {Node} subject - A node to search for as subject, or if null, a wildcard
-   * @param {Node} predicate - A node to search for as predicate, or if null, a wildcard
-   * @param {Node} object - A node to search for as object, or if null, a wildcard
-   * @param {Node} graph - A node to search for as graph, or if null, a wildcard
-   * @param {Boolean} justOne - flag - stop when found one rather than get all of them?
-   * @returns {Array<Node>} - An array of nodes which match the wildcard position
-   */
-  statementsMatching (subj, pred, obj, why, justOne) {
+   * @param subj - A node to search for as subject, or if null, a wildcard
+   * @param pred - A node to search for as predicate, or if null, a wildcard
+   * @param obj - A node to search for as object, or if null, a wildcard
+   * @param why - A node to search for as graph, or if null, a wildcard
+   * @param justOne - flag - stop when found one rather than get all of them?
+   * @returns An array of nodes which match the wildcard position
+   */
+  statementsMatching (
+    subj?: Quad_Subject | null,
+    pred?: Quad_Predicate | null,
+    obj?: Quad_Object | null,
+    why?: Quad_Graph | null,
+    justOne?: boolean
+  ): Quad[] {
     // log.debug("Matching {"+subj+" "+pred+" "+obj+"}")
     var pat = [ subj, pred, obj, why ]
-    var pattern = []
-    var hash = []
-    var wild = [] // wildcards
-    var given = [] // Not wild
-    var p
+    var pattern: Term[] = []
+    var hash: Indexable[] = []
+    var wild: number[] = [] // wildcards
+    var given: number[] = [] // Not wild
+    var p: number
     var list
     for (p = 0; p < 4; p++) {
       pattern[p] = this.canon(Node.fromValue(pat[p]))
@@ -830,12 +1094,12 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
     }
     // Ok, we have picked the shortest index but now we have to filter it
     var pBest = given[iBest]
-    var possibles = this.index[pBest][hash[pBest]]
+    var possibles: Quad[] = this.index[pBest][hash[pBest]]
     var check = given.slice(0, iBest).concat(given.slice(iBest + 1)) // remove iBest
-    var results = []
+    var results: Quad[] = []
     var parts = [ 'subject', 'predicate', 'object', 'why' ]
     for (var j = 0; j < possibles.length; j++) {
-      var st = possibles[j]
+      var st: Quad | null = possibles[j]
 
       for (i = 0; i < check.length; i++) { // for each position to be checked
         p = check[i]
@@ -853,13 +1117,14 @@ export default class IndexedFormula extends Formula { // IN future - allow pass
   }
 
   /**
-   *  A list of all the URIs by which this thing is known
+   * A list of all the URIs by which this thing is known
+   * @param term
    */
-  uris (term) {
+  uris(term: Quad_Subject): string[] {
     var cterm = this.canon(term)
     var terms = this.aliases[this.id(cterm)]
-    if (!cterm.uri) return []
-    var res = [ cterm.uri ]
+    if (!cterm.value) return []
+    var res = [ cterm.value ]
     if (terms) {
       for (var i = 0; i < terms.length; i++) {
         res.push(terms[i].uri)
diff --git a/src/tf-types.ts b/src/tf-types.ts
new file mode 100644
index 000000000..51ce2d661
--- /dev/null
+++ b/src/tf-types.ts
@@ -0,0 +1,173 @@
+import { SupportTable } from './factories/factory-types'
+import {
+  BlankNodeTermType,
+  DefaultGraphTermType,
+  LiteralTermType,
+  NamedNodeTermType,
+  VariableTermType,
+} from './types'
+
+/**
+ * RDF/JS spec Term
+ * @link https://rdf.js.org/data-model-spec/#term-interface
+ */
+export interface Term {
+  termType: string
+  value: string
+
+  /**
+   * Compare this term with {other} for structural equality
+   *
+   * Note that the task force spec only allows comparison with other terms
+   */
+  equals (other: Term): boolean
+}
+
+/**
+ * RDF/JS spec NamedNode
+ * @link https://rdf.js.org/data-model-spec/#namednode-interface
+ */
+export interface NamedNode extends Term {
+  termType: typeof NamedNodeTermType
+  value: string
+}
+
+/**
+ * RDF/JS spec Literal
+ * @link https://rdf.js.org/data-model-spec/#literal-interface
+ */
+export interface BlankNode extends Term {
+  termType: typeof BlankNodeTermType
+  value: string
+}
+
+/**
+ * RDF/JS spec Quad
+ * @link https://rdf.js.org/data-model-spec/#quad-interface
+ */
+export interface Quad<
+  S extends Term = Quad_Subject,
+  P extends Term = Quad_Predicate,
+  O extends Term = Quad_Object,
+  G extends Term = Quad_Graph
+> {
+  subject: S
+  predicate: P
+  object: O
+  graph: G
+}
+
+/**
+ * RDF/JS spec Literal
+ * @link https://rdf.js.org/data-model-spec/#literal-interface
+ */
+export interface Literal extends Term {
+  /** Contains the constant "Literal". */
+  termType: typeof LiteralTermType
+  /** The text value, unescaped, without language or type (example: "Brad Pitt") */
+  value: string
+  /**
+   * The language as lowercase BCP-47 [BCP47] string (examples: "en", "en-gb")
+   * or an empty string if the literal has no language.
+   */
+  language: string
+  /** A NamedNode whose IRI represents the datatype of the literal. */
+  datatype: NamedNode
+}
+
+/**
+ * RDF/JS spec Variable
+ * @link https://rdf.js.org/data-model-spec/#variable-interface
+ */
+export interface Variable extends Term {
+  /** Contains the constant "Variable". */
+  termType: typeof VariableTermType
+  /** The name of the variable without leading "?" (example: "a"). */
+  value: string
+}
+
+/**
+ * RDF/JS spec DefaultGraph
+ * An instance of DefaultGraph represents the default graph.
+ * It's only allowed to assign a DefaultGraph to the graph property of a Quad.
+ * @link https://rdf.js.org/data-model-spec/#defaultgraph-interface
+ */
+export interface DefaultGraph extends Term {
+  termType: typeof DefaultGraphTermType;
+  /** should return and empty string'' */
+  value: string;
+}
+
+/**
+ * RDF/JS spec DataFactory
+ *
+ * Not 100% compliant due to to practicality problems.
+ *
+ * @link https://rdf.js.org/data-model-spec/#datafactory-interface
+ */
+export interface RdfJsDataFactory {
+  /** Returns a new instance of NamedNode. */
+  namedNode: (value: string) => NamedNode,
+
+  /**
+   * Returns a new instance of BlankNode.
+   * If the value parameter is undefined a new identifier for the
+   * blank node is generated for each call.
+   */
+  blankNode: (value?: string) => BlankNode,
+
+  /**
+   * Returns a new instance of Literal.
+   * If languageOrDatatype is a NamedNode, then it is used for the value of datatype.
+   * Otherwise languageOrDatatype is used for the value of language. */
+  literal: (value: string, languageOrDatatype: string | NamedNode) => Literal,
+
+  /** Returns a new instance of Variable. This method is optional. */
+  variable?: (value: string) => Variable,
+
+  /**
+   * Returns an instance of DefaultGraph.
+   */
+  defaultGraph: () => DefaultGraph | NamedNode | BlankNode,
+
+  /**
+   * Returns a new instance of the specific Term subclass given by original.termType
+   * (e.g., NamedNode, BlankNode, Literal, etc.),
+   * such that newObject.equals(original) returns true.
+   * Not implemented in RDFJS, so optional.
+   */
+  fromTerm?: (original: Term) => Term
+
+  /**
+   * Returns a new instance of Quad, such that newObject.equals(original) returns true.
+   * Not implemented in RDFJS, so optional.
+   */
+  fromQuad?: (original: Quad) => Quad
+
+  /**
+   * Returns a new instance of Quad.
+   * If graph is undefined or null it MUST set graph to a DefaultGraph.
+   */
+  quad: (
+    subject: Term,
+    predicate: Term,
+    object: Term,
+    graph?: Term,
+  ) => Quad<any, any, any, any>
+
+  /**
+   * Check for specific features/behaviour on the factory.
+   *
+   * This does not exist on the original RDF/JS spec
+   */
+  supports: SupportTable
+}
+
+/** A RDF/JS spec Subject */
+export type Quad_Subject = NamedNode | BlankNode | Variable
+/** A RDF/JS spec Predicate */
+export type Quad_Predicate = NamedNode | Variable
+/** A RDF/JS spec Object */
+export type Quad_Object = NamedNode | BlankNode | Literal | Variable
+/** A RDF/JS spec Graph */
+export type Quad_Graph = NamedNode | DefaultGraph | BlankNode | Variable
diff --git a/src/types.ts b/src/types.ts
new file mode 100644
index 000000000..813f9e484
--- /dev/null
+++ b/src/types.ts
@@ -0,0 +1,107 @@
+import Node from './node-internal'
+import RDFlibVariable from './variable'
+import RDFlibBlankNode from './blank-node'
+import Collection from './collection'
+import RDFlibLiteral from './literal'
+import RDFlibNamedNode from './named-node'
+import RDFlibDefaultGraph from './default-graph'
+import { DataFactory } from './factories/factory-types'
+import IndexedFormula from './store'
+import Fetcher from './fetcher'
+import Statement from './statement'
+import Empty from './empty'
+import { NamedNode, Term } from './tf-types'
+
+export const NamedNodeTermType = "NamedNode" as const
+export const BlankNodeTermType = "BlankNode" as const
+export const LiteralTermType = "Literal" as const
+export const VariableTermType = "Variable" as const
+export const DefaultGraphTermType = "DefaultGraph" as const
+// Non-RDF/JS types:
+export const CollectionTermType = "Collection" as const
+export const EmptyTermType = "Empty" as const
+export const GraphTermType = "Graph" as const
+
+export type TermType = typeof NamedNodeTermType
+  | typeof BlankNodeTermType
+  | typeof LiteralTermType
+  | typeof VariableTermType
+  | typeof DefaultGraphTermType
+  | typeof CollectionTermType
+  | typeof EmptyTermType
+  | typeof GraphTermType
+
+export const HTMLContentType = "text/html" as const
+export const JSONLDContentType = "application/ld+json" as const
+export const N3ContentType = "text/n3" as const
+export const N3LegacyContentType = "application/n3" as const
+export const NQuadsAltContentType = "application/nquads" as const
+export const NQuadsContentType = "application/n-quads" as const
+export const NTriplesContentType = "application/n-triples" as const
+export const RDFXMLContentType = "application/rdf+xml" as const
+export const SPARQLUpdateContentType = "application/sparql-update" as const
+export const TurtleContentType = "text/turtle" as const
+export const TurtleLegacyContentType = "application/x-turtle" as const
+export const XHTMLContentType = "application/xhtml+xml" as const
+
+/**
+ * A valid mime type header
+ */
+export type ContentType = typeof RDFXMLContentType
+  | typeof HTMLContentType
+  | typeof JSONLDContentType
+  | typeof N3ContentType
+  | typeof N3LegacyContentType
+  | typeof NQuadsAltContentType
+  | typeof NQuadsContentType
+  | typeof SPARQLUpdateContentType
+  | typeof TurtleContentType
+  | typeof TurtleLegacyContentType
+  | typeof XHTMLContentType
+
+/** A type for values that serves as inputs */
+export type ValueType = Term | Node | Date | string | number | boolean | undefined | null | Collection
+
+/**
+ * In this project, there exist two types for the same kind of RDF concept.
+ * We have RDF/JS spec types (standardized, generic), and RDFlib types (internal, specific).
+ * When deciding which type to use in a function, it is preferable to accept generic inputs,
+ * whenever possible, and provide strict outputs.
+ * In some ways, the TF types in here are a bit more strict.
+ * Variables are missing, and the statement requires specific types of terms (e.g. NamedNode instead of Term).
+ */
+
+/** An RDF/JS Subject */
+export type SubjectType = RDFlibBlankNode | RDFlibNamedNode | RDFlibVariable
+/** An RDF/JS Predicate */
+export type PredicateType = RDFlibNamedNode | RDFlibVariable
+/** An RDF/JS Object */
+export type ObjectType = RDFlibNamedNode | RDFlibLiteral | Collection | RDFlibBlankNode | RDFlibVariable | Empty
+/** An RDF/JS Graph */
+export type GraphType = RDFlibDefaultGraph | RDFlibNamedNode | RDFlibVariable // | Formula
+
+export interface Bindings {
+  [id: string]: Term;
+}
+
+/** All the types that a .fromValue() method might return */
+export type FromValueReturns<C extends Node = any> = Term | undefined | null | Collection<C>
+
+export interface IRDFlibDataFactory extends DataFactory<
+  RDFlibNamedNode | RDFlibBlankNode | RDFlibLiteral | Collection | Statement
+> {
+  fetcher: (store: IndexedFormula, options: any) => Fetcher
+  graph: (features, opts) => IndexedFormula
+  lit: (val: string, lang?: string, dt?: NamedNode) => RDFlibLiteral
+  st: (
+    subject: SubjectType,
+    predicate: PredicateType,
+    object: ObjectType,
+    graph?: GraphType
+  ) => Statement
+  triple: (
+    subject: SubjectType,
+    predicate: PredicateType,
+    object: ObjectType
+  ) => Statement
+}
diff --git a/src/update-manager.js b/src/update-manager.ts
similarity index 76%
rename from src/update-manager.js
rename to src/update-manager.ts
index 294c19057..76146bc5b 100644
--- a/src/update-manager.js
+++ b/src/update-manager.ts
@@ -7,34 +7,63 @@
 import IndexedFormula from './store'
 import { docpart } from './uri'
 import Fetcher from './fetcher'
-import DataFactory from './data-factory'
 import Namespace from './namespace'
 import Serializer from './serializer'
 import { join as uriJoin } from './uri'
-import { isStore } from './util'
-import * as Util from './util'
+import { isStore, isBlankNode } from './utils/terms'
+import * as Util from './utils-js'
+import Statement from './statement'
+import RDFlibNamedNode from './named-node'
+import { termValue } from './utils/termValue'
+import {
+  BlankNode,
+  NamedNode,
+  Quad_Graph,
+  Quad_Object,
+  Quad_Predicate,
+  Quad_Subject,
+  Quad,
+  Term,
+} from './tf-types'
+
+interface UpdateManagerFormula extends IndexedFormula {
+  fetcher: Fetcher
+}
+
+type CallBackFunction = (uri: string, ok: boolean, message: string, response: Error | Response) => {} | void
 
-/** Update Manager
-*
-* The update manager is a helper object for a store.
+/**
+* The UpdateManager is a helper object for a store.
 * Just as a Fetcher provides the store with the ability to read and write,
 * the Update Manager provides functionality for making small patches in real time,
 * and also looking out for concurrent updates from other agents
 */
-
 export default class UpdateManager {
-  /** @constructor
-   * @param {IndexedFormula} store - the quadstore to store data and metadata. Created if not passed.f
+
+  store: UpdateManagerFormula
+
+  ifps: {}
+
+  fps: {}
+
+  /** Index of objects for coordinating incoming and outgoing patches */
+  patchControl: []
+
+  /** Object of namespaces */
+  ns: any
+
+  /**
+   * @param  store - The quadstore to store data and metadata. Created if not passed.
   */
-  constructor (store) {
-    store = store || new IndexedFormula() // If none provided make a store
-    this.store = store
+  constructor (store?: IndexedFormula) {
+    store = store || new IndexedFormula()
     if (store.updater) {
       throw new Error("You can't have two UpdateManagers for the same store")
     }
-    if (!store.fetcher) { // The store must also/already have a fetcher
-      store.fetcher = new Fetcher(store)
+    if (!(store as UpdateManagerFormula).fetcher) {
+      (store as UpdateManagerFormula).fetcher = new Fetcher(store)
     }
+    this.store = store as UpdateManagerFormula
     store.updater = this
     this.ifps = {}
     this.fps = {}
@@ -48,14 +77,14 @@ export default class UpdateManager {
     this.ns.rdf = Namespace('http://www.w3.org/1999/02/22-rdf-syntax-ns#')
     this.ns.owl = Namespace('http://www.w3.org/2002/07/owl#')
 
-    this.patchControl = [] // index of objects fro coordinating incomng and outgoing patches
+    this.patchControl = []
   }
 
-  patchControlFor (doc) {
-    if (!this.patchControl[doc.uri]) {
-      this.patchControl[doc.uri] = []
+  patchControlFor (doc: NamedNode) {
+    if (!this.patchControl[doc.value]) {
+      this.patchControl[doc.value] = []
     }
-    return this.patchControl[doc.uri]
+    return this.patchControl[doc.value]
   }
 
   /**
@@ -64,26 +93,23 @@ export default class UpdateManager {
    *   for safety.
    * We don't actually check for write access on files.
    *
-   * @param uri {string}
-   * @param kb {IndexedFormula}
-   *
-   * @returns {string|boolean|undefined} The method string SPARQL or DAV or
+   * @returns The method string SPARQL or DAV or
    *   LOCALFILE or false if known, undefined if not known.
    */
-  editable (uri, kb) {
+  editable (uri: string | NamedNode, kb: IndexedFormula): string | boolean | undefined {
     if (!uri) {
       return false // Eg subject is bnode, no known doc to write to
     }
     if (!kb) {
       kb = this.store
     }
-    uri = uri.uri || uri // Allow Named Node to be passed
+    uri = termValue(uri)
 
-    if (uri.slice(0, 8) === 'file:///') {
+    if ((uri as string).slice(0, 8) === 'file:///') {
       if (kb.holds(
-            kb.sym(uri),
-            DataFactory.namedNode('http://www.w3.org/1999/02/22-rdf-syntax-ns#type'),
-            DataFactory.namedNode('http://www.w3.org/2007/ont/link#MachineEditableDocument'))) {
+          this.store.rdfFactory.namedNode(uri),
+          this.store.rdfFactory.namedNode('http://www.w3.org/1999/02/22-rdf-syntax-ns#type'),
+          this.store.rdfFactory.namedNode('http://www.w3.org/2007/ont/link#MachineEditableDocument'))) {
         return 'LOCALFILE'
       }
 
@@ -91,7 +117,7 @@ export default class UpdateManager {
 
       console.log('UpdateManager.editable: Not MachineEditableDocument file ' +
         uri + '\n')
-      console.log(sts.map((x) => { return x.toNT() }).join('\n'))
+      console.log(sts.map((x) => { return (x as Statement).toNT() }).join('\n'))
 
       return false
       // @@ Would be nifty of course to see whether we actually have write access first.
@@ -99,6 +125,7 @@ export default class UpdateManager {
 
     var request
     var definitive = false
+     // @ts-ignore passes a string to kb.each, which expects a term. Should this work?
     var requests = kb.each(undefined, this.ns.link('requestedURI'), docpart(uri))
 
     // This if-statement does not follow the Solid spec, but temporarily reverts this change:
@@ -110,14 +137,14 @@ export default class UpdateManager {
     // https://github.com/solid/node-solid-server/pull/1313
     // Once that release has been published to the major Pod hosters, the commit that introduced
     // this statement should be reverted:
-    if (kb.holds(DataFactory.namedNode(uri), this.ns.rdf('type'), this.ns.ldp('Resource'))) {
+    if (kb.holds(this.store.rdfFactory.namedNode(uri), this.ns.rdf('type'), this.ns.ldp('Resource'))) {
         return 'SPARQL'
     }
-    var method
+    var method: string
     for (var r = 0; r < requests.length; r++) {
       request = requests[r]
       if (request !== undefined) {
-        var response = kb.any(request, this.ns.link('response'))
+        var response = kb.any(request, this.ns.link('response')) as Quad_Subject
         if (request !== undefined) {
           var wacAllow = kb.anyValue(response, this.ns.httph('wac-allow'))
           if (wacAllow) {
@@ -151,6 +178,7 @@ export default class UpdateManager {
           var status = kb.each(response, this.ns.http('status'))
           if (status.length) {
             for (let i = 0; i < status.length; i++) {
+              // @ts-ignore since statuses should be TFTerms, this should always be false
               if (status[i] === 200 || status[i] === 404) {
                 definitive = true
                 // return false // A definitive answer
@@ -179,7 +207,7 @@ export default class UpdateManager {
       : obj.toNT()
   }
 
-  anonymizeNT (stmt) {
+  anonymizeNT (stmt: Quad) {
     return this.anonymize(stmt.subject) + ' ' +
       this.anonymize(stmt.predicate) + ' ' +
       this.anonymize(stmt.object) + ' .'
@@ -189,23 +217,23 @@ export default class UpdateManager {
    * Returns a list of all bnodes occurring in a statement
    * @private
    */
-  statementBnodes (st) {
+  statementBnodes (st: Quad): BlankNode[] {
     return [st.subject, st.predicate, st.object].filter(function (x) {
-      return x.isBlank
-    })
+      return isBlankNode(x)
+    }) as BlankNode[]
   }
 
   /**
    * Returns a list of all bnodes occurring in a list of statements
    * @private
    */
-  statementArrayBnodes (sts) {
-    var bnodes = []
+  statementArrayBnodes (sts: Quad[]) {
+    var bnodes: BlankNode[] = []
     for (let i = 0; i < sts.length; i++) {
       bnodes = bnodes.concat(this.statementBnodes(sts[i]))
     }
     bnodes.sort() // in place sort - result may have duplicates
-    var bnodes2 = []
+    var bnodes2: BlankNode[] = []
     for (let j = 0; j < bnodes.length; j++) {
       if (j === 0 || !bnodes[j].equals(bnodes[j - 1])) {
         bnodes2.push(bnodes[j])
@@ -223,12 +251,12 @@ export default class UpdateManager {
     var a = this.store.each(undefined, this.ns.rdf('type'),
       this.ns.owl('InverseFunctionalProperty'))
     for (let i = 0; i < a.length; i++) {
-      this.ifps[a[i].uri] = true
+      this.ifps[a[i].value] = true
     }
     this.fps = {}
     a = this.store.each(undefined, this.ns.rdf('type'), this.ns.owl('FunctionalProperty'))
     for (let i = 0; i < a.length; i++) {
-      this.fps[a[i].uri] = true
+      this.fps[a[i].value] = true
     }
   }
 
@@ -244,7 +272,7 @@ export default class UpdateManager {
     var y
     var res
     for (let i = 0; i < sts.length; i++) {
-      if (this.fps[sts[i].predicate.uri]) {
+      if (this.fps[sts[i].predicate.value]) {
         y = sts[i].subject
         if (!y.isBlank) {
           return [ sts[i] ]
@@ -260,7 +288,7 @@ export default class UpdateManager {
     // outgoing links
     sts = this.store.statementsMatching(x, undefined, undefined, source)
     for (let i = 0; i < sts.length; i++) {
-      if (this.ifps[sts[i].predicate.uri]) {
+      if (this.ifps[sts[i].predicate.value]) {
         y = sts[i].object
         if (!y.isBlank) {
           return [ sts[i] ]
@@ -296,9 +324,9 @@ export default class UpdateManager {
    * @private
    */
   mentioned (x) {
-    return this.store.statementsMatching(x).length !== 0 || // Don't pin fresh bnodes
-      this.store.statementsMatching(undefined, x).length !== 0 ||
-      this.store.statementsMatching(undefined, undefined, x).length !== 0
+    return this.store.statementsMatching(x, null, null, null).length !== 0 || // Don't pin fresh bnodes
+      this.store.statementsMatching(null, x).length !== 0 ||
+      this.store.statementsMatching(null, null, x).length !== 0
   }
 
   /**
@@ -321,9 +349,9 @@ export default class UpdateManager {
    * Returns the best context for a single statement
    * @private
    */
-  statementContext (st) {
+  statementContext (st: Quad) {
     var bnodes = this.statementBnodes(st)
-    return this.bnodeContext(bnodes, st.why)
+    return this.bnodeContext(bnodes, st.graph)
   }
 
   /**
@@ -342,7 +370,11 @@ export default class UpdateManager {
   /**
    * @private
    */
-  fire (uri, query, callbackFunction) {
+  fire (
+    uri: string,
+    query: string,
+    callbackFunction: CallBackFunction
+  ): Promise<void> {
     return Promise.resolve()
       .then(() => {
         if (!uri) {
@@ -369,7 +401,7 @@ export default class UpdateManager {
 
         console.log('UpdateManager: update Ok for <' + uri + '>')
 
-        callbackFunction(uri, response.ok, response.responseText, response)
+        callbackFunction(uri, response.ok, response.responseText as string, response)
       })
       .catch(err => {
         callbackFunction(uri, false, err.message, err)
@@ -384,15 +416,15 @@ export default class UpdateManager {
    * It returns an object which includes
    *  function which can be used to change the object of the statement.
    */
-  update_statement (statement) {
-    if (statement && !statement.why) {
+  update_statement (statement: Quad) {
+    if (statement && !statement.graph) {
       return
     }
     var updater = this
     var context = this.statementContext(statement)
 
     return {
-      statement: statement ? [statement.subject, statement.predicate, statement.object, statement.why] : undefined,
+      statement: statement ? [statement.subject, statement.predicate, statement.object, statement.graph] : undefined,
       statementNT: statement ? this.anonymizeNT(statement) : undefined,
       where: updater.contextWhere(context),
 
@@ -400,16 +432,19 @@ export default class UpdateManager {
         var query = this.where
         query += 'DELETE DATA { ' + this.statementNT + ' } ;\n'
         query += 'INSERT DATA { ' +
+          // @ts-ignore `this` might refer to the wrong scope. Does this work?
           this.anonymize(this.statement[0]) + ' ' +
+          // @ts-ignore
           this.anonymize(this.statement[1]) + ' ' +
+          // @ts-ignore
           this.anonymize(obj) + ' ' + ' . }\n'
 
-        updater.fire(this.statement[3].uri, query, callbackFunction)
+        updater.fire((this.statement as [Quad_Subject, Quad_Predicate, Quad_Object, Quad_Graph])[3].value, query, callbackFunction)
       }
     }
   }
 
-  insert_statement (st, callbackFunction) {
+  insert_statement (st: Quad, callbackFunction: CallBackFunction): void {
     var st0 = st instanceof Array ? st[0] : st
     var query = this.contextWhere(this.statementContext(st0))
 
@@ -424,10 +459,10 @@ export default class UpdateManager {
         this.anonymize(st.object) + ' ' + ' . }\n'
     }
 
-    this.fire(st0.why.uri, query, callbackFunction)
+    this.fire(st0.graph.value, query, callbackFunction)
   }
 
-  delete_statement (st, callbackFunction) {
+  delete_statement (st: Quad | Quad[], callbackFunction: CallBackFunction): void {
     var st0 = st instanceof Array ? st[0] : st
     var query = this.contextWhere(this.statementContext(st0))
 
@@ -442,7 +477,7 @@ export default class UpdateManager {
         this.anonymize(st.object) + ' ' + ' . }\n'
     }
 
-    this.fire(st0.why.uri, query, callbackFunction)
+    this.fire(st0.graph.value, query, callbackFunction)
   }
 
 /// //////////////////////
@@ -456,7 +491,7 @@ export default class UpdateManager {
    * @param doc
    * @param action
    */
-  requestDownstreamAction (doc, action) {
+  requestDownstreamAction (doc: NamedNode, action): void {
     var control = this.patchControlFor(doc)
     if (!control.pendingUpstream) {
       action(doc)
@@ -475,27 +510,27 @@ export default class UpdateManager {
    * We want to start counting websocket notifications
    * to distinguish the ones from others from our own.
    */
-  clearUpstreamCount (doc) {
+  clearUpstreamCount (doc: NamedNode): void {
     var control = this.patchControlFor(doc)
     control.upstreamCount = 0
   }
 
-  getUpdatesVia (doc) {
+  getUpdatesVia (doc: NamedNode): string | null {
     var linkHeaders = this.store.fetcher.getHeader(doc, 'updates-via')
     if (!linkHeaders || !linkHeaders.length) return null
     return linkHeaders[0].trim()
   }
 
-  addDownstreamChangeListener (doc, listener) {
+  addDownstreamChangeListener (doc: NamedNode, listener): void {
     var control = this.patchControlFor(doc)
     if (!control.downstreamChangeListeners) { control.downstreamChangeListeners = [] }
     control.downstreamChangeListeners.push(listener)
-    this.setRefreshHandler(doc, (doc) => {
+    this.setRefreshHandler(doc, (doc: NamedNode) => {
       this.reloadAndSync(doc)
     })
   }
 
-  reloadAndSync (doc) {
+  reloadAndSync (doc: NamedNode): void {
     var control = this.patchControlFor(doc)
     var updater = this
 
@@ -524,14 +559,14 @@ export default class UpdateManager {
           }
         } else {
           control.reloading = false
-          if (response.status === 0) {
+          if ((response as Response).status === 0) {
             console.log('Network error refreshing the data. Retrying in ' +
               retryTimeout / 1000)
             control.reloading = true
             retryTimeout = retryTimeout * 2
             setTimeout(tryReload, retryTimeout)
           } else {
-            console.log('Error ' + response.status + 'refreshing the data:' +
+            console.log('Error ' + (response as Response).status + 'refreshing the data:' +
               message + '. Stopped' + doc)
           }
         }
@@ -557,8 +592,8 @@ export default class UpdateManager {
    *
    * @returns {boolean}
    */
-  setRefreshHandler (doc, handler) {
-    var wssURI = this.getUpdatesVia(doc) // relative
+  setRefreshHandler (doc: NamedNode, handler): boolean {
+    let wssURI = this.getUpdatesVia(doc) // relative
     // var kb = this.store
     var theHandler = handler
     var self = this
@@ -571,19 +606,17 @@ export default class UpdateManager {
       return false
     }
 
-    wssURI = uriJoin(wssURI, doc.uri)
-    wssURI = wssURI.replace(/^http:/, 'ws:').replace(/^https:/, 'wss:')
+    wssURI = uriJoin(wssURI, doc.value)
+    const validWssURI = wssURI.replace(/^http:/, 'ws:').replace(/^https:/, 'wss:')
     console.log('Web socket URI ' + wssURI)
 
     var openWebsocket = function () {
       // From https://github.com/solid/solid-spec#live-updates
       var socket
       if (typeof WebSocket !== 'undefined') {
-        socket = new WebSocket(wssURI)
-      } else if (typeof Services !== 'undefined') { // Firefox add on http://stackoverflow.com/questions/24244886/is-websocket-supported-in-firefox-for-android-addons
-        socket = (Services.wm.getMostRecentWindow('navigator:browser').WebSocket)(wssURI)
+        socket = new WebSocket(validWssURI)
       } else if (typeof window !== 'undefined' && window.WebSocket) {
-        socket = window.WebSocket(wssURI)
+        socket = (window as any).WebSocket(validWssURI)
       } else {
         console.log('Live update disabled, as WebSocket not supported by platform :-(')
         return
@@ -591,7 +624,7 @@ export default class UpdateManager {
       socket.onopen = function () {
         console.log('    websocket open')
         retryTimeout = 1500 // reset timeout to fast on success
-        this.send('sub ' + doc.uri)
+        this.send('sub ' + doc.value)
         if (retries) {
           console.log('Web socket has been down, better check for any news.')
           updater.requestDownstreamAction(doc, theHandler)
@@ -600,7 +633,7 @@ export default class UpdateManager {
       var control = self.patchControlFor(doc)
       control.upstreamCount = 0
 
-      socket.onerror = function onerror (err) {
+      socket.onerror = function onerror (err: Error) {
         console.log('Error on Websocket:', err)
       }
 
@@ -617,9 +650,9 @@ export default class UpdateManager {
       // 1006  CLOSE_ABNORMAL  Reserved. Used to indicate that a connection was closed abnormally (
       //
       //
-      socket.onclose = function (event) {
+      socket.onclose = function (event: CloseEvent) {
         console.log('*** Websocket closed with code ' + event.code +
-          ", reason '" + event.reason + "' clean = " + event.clean)
+          ", reason '" + event.reason + "' clean = " + event.wasClean)
         retryTimeout *= 2
         retries += 1
         console.log('Retrying in ' + retryTimeout + 'ms') // (ask user?)
@@ -628,7 +661,7 @@ export default class UpdateManager {
           openWebsocket()
         }, retryTimeout)
       }
-      socket.onmessage = function (msg) {
+      socket.onmessage = function (msg: MessageEvent) {
         if (msg.data && msg.data.slice(0, 3) === 'pub') {
           if ('upstreamCount' in control) {
             control.upstreamCount -= 1
@@ -648,25 +681,27 @@ export default class UpdateManager {
     return true
   }
 
-  /** Update
-   *
-   * This high-level function updates the local store iff the web is changed
-   * successfully.
-   *
-   * Deletions, insertions may be undefined or single statements or lists or formulae
-   * (may contain bnodes which can be indirectly identified by a where clause).
-   * The `why` property of each statement must be the same and give the web document to be updated
-   *
-   * @param deletions - Statement or statments to be deleted.
-   * @param insertions - Statement or statements to be inserted
-   *
-   * @param callbackFunction {Function} called as callbackFunction(uri, success, errorbody)
-   *              OR returns a promise
-   *
-   * @returns {*}
+  /**
+   * This high-level function updates the local store iff the web is changed successfully.
+   * Deletions, insertions may be undefined or single statements or lists or formulae (may contain bnodes which can be indirectly identified by a where clause).
+   * The `why` property of each statement must be the same and give the web document to be updated.
+   * @param deletions - Statement or statements to be deleted.
+   * @param insertions - Statement or statements to be inserted.
+   * @param callback - called as callbackFunction(uri, success, errorbody)
+   *           OR returns a promise
    */
-  update (deletions, insertions, callbackFunction, secondTry) {
-    if (!callbackFunction) {
+  update(
+      deletions: ReadonlyArray<Statement>,
+      insertions: ReadonlyArray<Statement>,
+      callback?: (
+        uri: string | undefined | null,
+        success: boolean,
+        errorBody?: string,
+        response?: Response | Error
+      ) => void,
+      secondTry?: boolean
+  ): void | Promise<void> {
+    if (!callback) {
       var thisUpdater = this
       return new Promise(function (resolve, reject) { // Promise version
         thisUpdater.update(deletions, insertions, function (uri, ok, errorBody) {
@@ -694,9 +729,9 @@ export default class UpdateManager {
         throw new Error('Type Error ' + (typeof is) + ': ' + is)
       }
       if (ds.length === 0 && is.length === 0) {
-        return callbackFunction(null, true) // success -- nothing needed to be done.
+        return callback(null, true) // success -- nothing needed to be done.
       }
-      var doc = ds.length ? ds[0].why : is[0].why
+      var doc = ds.length ? ds[0].graph : is[0].graph
       if (!doc) {
         let message = 'Error patching: statement does not specify which document to patch:' + ds[0] + ', ' + is[0]
         console.log(message)
@@ -709,10 +744,10 @@ export default class UpdateManager {
       var verbs = ['insert', 'delete']
       var clauses = { 'delete': ds, 'insert': is }
       verbs.map(function (verb) {
-        clauses[verb].map(function (st) {
-          if (!doc.equals(st.why)) {
+        clauses[verb].map(function (st: Quad) {
+          if (!doc.equals(st.graph)) {
             throw new Error('update: destination ' + doc +
-              ' inconsistent with delete quad ' + st.why)
+              ' inconsistent with delete quad ' + st.graph)
           }
           props.map(function (prop) {
             if (typeof st[prop] === 'undefined') {
@@ -722,7 +757,7 @@ export default class UpdateManager {
         })
       })
 
-      var protocol = this.editable(doc.uri, kb)
+      var protocol = this.editable(doc.value, kb)
       if (protocol === false) {
         throw new Error('Update: Can\'t make changes in uneditable ' + doc)
       }
@@ -730,15 +765,15 @@ export default class UpdateManager {
         if (secondTry) {
           throw new Error('Update: Loaded ' + doc + "but stil can't figure out what editing protcol it supports.")
         }
-        console.log(`Update: have not loaded ${doc} before: loading now...`)
-        this.store.fetcher.load(doc).then(response => {
-          this.update(deletions, insertions, callbackFunction, true) // secondTry
+        console.log(`Update: have not loaded ${doc} before: loading now...`);
+        (this.store.fetcher.load(doc) as Promise<Response>).then(response => {
+          this.update(deletions, insertions, callback, true)
         }, err => {
           throw new Error(`Update: Can't read ${doc} before patching: ${err}`)
         })
         return
-      } else if (protocol.indexOf('SPARQL') >= 0) {
-        var bnodes = []
+      } else if ((protocol as string).indexOf('SPARQL') >= 0) {
+        var bnodes: BlankNode[] = []
         if (ds.length) bnodes = this.statementArrayBnodes(ds)
         if (is.length) bnodes = bnodes.concat(this.statementArrayBnodes(is))
         var context = this.bnodeContext(bnodes, doc)
@@ -784,11 +819,11 @@ export default class UpdateManager {
           console.log('upstream count up to : ' + control.upstreamCount)
         }
 
-        this.fire(doc.uri, query, (uri, success, body, response) => {
-          response.elapsedTimeMs = Date.now() - startTime
+        this.fire(doc.value, query, (uri, success, body, response) => {
+          (response as any).elapsedTimeMs = Date.now() - startTime
           console.log('    UpdateManager: Return ' +
-            (success ? 'success ' : 'FAILURE ') + response.status +
-            ' elapsed ' + response.elapsedTimeMs + 'ms')
+            (success ? 'success ' : 'FAILURE ') + (response as Response).status +
+            ' elapsed ' + (response as any).elapsedTimeMs + 'ms')
           if (success) {
             try {
               kb.remove(ds)
@@ -801,7 +836,7 @@ export default class UpdateManager {
             }
           }
 
-          callbackFunction(uri, success, body, response)
+          callback(uri, success, body, response)
           control.pendingUpstream -= 1
           // When upstream patches have been sent, reload state if downstream waiting
           if (control.pendingUpstream === 0 && control.downstreamAction) {
@@ -811,15 +846,15 @@ export default class UpdateManager {
             downstreamAction(doc)
           }
         })
-      } else if (protocol.indexOf('DAV') >= 0) {
-        this.updateDav(doc, ds, is, callbackFunction)
+      } else if ((protocol as string).indexOf('DAV') >= 0) {
+        this.updateDav(doc, ds, is, callback)
       } else {
-        if (protocol.indexOf('LOCALFILE') >= 0) {
+        if ((protocol as string).indexOf('LOCALFILE') >= 0) {
           try {
-            this.updateLocalFile(doc, ds, is, callbackFunction)
+            this.updateLocalFile(doc, ds, is, callback)
           } catch (e) {
-            callbackFunction(doc.uri, false,
-              'Exception trying to write back file <' + doc.uri + '>\n'
+            callback(doc.value, false,
+              'Exception trying to write back file <' + doc.value + '>\n'
               // + tabulator.Util.stackString(e))
             )
           }
@@ -828,12 +863,17 @@ export default class UpdateManager {
         }
       }
     } catch (e) {
-      callbackFunction(undefined, false, 'Exception in update: ' + e + '\n' +
+      callback(undefined, false, 'Exception in update: ' + e + '\n' +
         Util.stackString(e))
     }
   }
 
-  updateDav (doc, ds, is, callbackFunction) {
+  updateDav (
+    doc: Quad_Subject,
+    ds,
+    is,
+    callbackFunction
+  ): null | Promise<void> {
     let kb = this.store
     // The code below is derived from Kenny's UpdateCenter.js
     var request = kb.any(doc, this.ns.link('request'))
@@ -841,11 +881,11 @@ export default class UpdateManager {
       throw new Error('No record of our HTTP GET request for document: ' +
         doc)
     } // should not happen
-    var response = kb.any(request, this.ns.link('response'))
+    var response = kb.any(request as NamedNode, this.ns.link('response')) as Quad_Subject
     if (!response) {
       return null // throw "No record HTTP GET response for document: "+doc
     }
-    var contentType = kb.the(response, this.ns.httph('content-type')).value
+    var contentType = (kb.the(response, this.ns.httph('content-type'))as Term).value
 
     // prepare contents of revised document
     let newSts = kb.statementsMatching(undefined, undefined, undefined, doc).slice() // copy!
@@ -856,7 +896,7 @@ export default class UpdateManager {
       newSts.push(is[i])
     }
 
-    const documentString = this.serialize(doc.uri, newSts, contentType)
+    const documentString = this.serialize(doc.value, newSts, contentType)
 
     // Write the new version back
     var candidateTarget = kb.the(response, this.ns.httph('content-location'))
@@ -884,10 +924,10 @@ export default class UpdateManager {
           kb.add(is[i].subject, is[i].predicate, is[i].object, doc)
         }
 
-        callbackFunction(doc.uri, response.ok, response.responseText, response)
+        callbackFunction(doc.value, response.ok, response.responseText, response)
       })
       .catch(err => {
-        callbackFunction(doc.uri, false, err.message, err)
+        callbackFunction(doc.value, false, err.message, err)
       })
   }
 
@@ -899,7 +939,7 @@ export default class UpdateManager {
    * @param is
    * @param callbackFunction
    */
-  updateLocalFile (doc, ds, is, callbackFunction) {
+  updateLocalFile (doc: NamedNode, ds, is, callbackFunction): void {
     const kb = this.store
     console.log('Writing back to local file\n')
     // See http://simon-jung.blogspot.com/2007/10/firefox-extension-file-io.html
@@ -913,29 +953,31 @@ export default class UpdateManager {
       newSts.push(is[ i ])
     }
     // serialize to the appropriate format
-    var dot = doc.uri.lastIndexOf('.')
+    var dot = doc.value.lastIndexOf('.')
     if (dot < 1) {
-      throw new Error('Rewriting file: No filename extension: ' + doc.uri)
+      throw new Error('Rewriting file: No filename extension: ' + doc.value)
     }
-    var ext = doc.uri.slice(dot + 1)
+    var ext = doc.value.slice(dot + 1)
 
     let contentType = Fetcher.CONTENT_TYPE_BY_EXT[ ext ]
     if (!contentType) {
       throw new Error('File extension .' + ext + ' not supported for data write')
     }
 
-    const documentString = this.serialize(doc.uri, newSts, contentType)
+    const documentString = this.serialize(doc.value, newSts, contentType)
 
     // Write the new version back
     // create component for file writing
     console.log('Writing back: <<<' + documentString + '>>>')
-    var filename = doc.uri.slice(7) // chop off   file://  leaving /path
+    var filename = doc.value.slice(7) // chop off   file://  leaving /path
     // console.log("Writeback: Filename: "+filename+"\n")
+    // @ts-ignore Where does Component come from? Perhaps deprecated?
     var file = Components.classes[ '@mozilla.org/file/local;1' ]
+    // @ts-ignore Where does Component come from? Perhaps deprecated?
       .createInstance(Components.interfaces.nsILocalFile)
     file.initWithPath(filename)
     if (!file.exists()) {
-      throw new Error('Rewriting file <' + doc.uri +
+      throw new Error('Rewriting file <' + doc.value +
         '> but it does not exist!')
     }
     // {
@@ -943,7 +985,9 @@ export default class UpdateManager {
     // }
     // create file output stream and use write/create/truncate mode
     // 0x02 writing, 0x08 create file, 0x20 truncate length if exist
+    // @ts-ignore Where does Component come from? Perhaps deprecated?
     var stream = Components.classes[ '@mozilla.org/network/file-output-stream;1' ]
+    // @ts-ignore Where does Component come from? Perhaps deprecated?
       .createInstance(Components.interfaces.nsIFileOutputStream)
 
     // Various JS systems object to 0666 in struct mode as dangerous
@@ -959,19 +1003,15 @@ export default class UpdateManager {
     for (let i = 0; i < is.length; i++) {
       kb.add(is[ i ].subject, is[ i ].predicate, is[ i ].object, doc)
     }
-    callbackFunction(doc.uri, true, '') // success!
+    callbackFunction(doc.value, true, '') // success!
   }
 
   /**
-   * @param uri {string}
-   * @param data {string|Array<Statement>}
-   * @param contentType {string}
-   *
    * @throws {Error} On unsupported content type
    *
    * @returns {string}
    */
-  serialize (uri, data, contentType) {
+  serialize (uri: string, data: string | Quad[], contentType: string): string {
     const kb = this.store
     let documentString
 
@@ -1003,35 +1043,31 @@ export default class UpdateManager {
   }
 
   /**
-   * This is suitable for an initial creation of a document
-   *
-   * @param doc {Node}
-   * @param data {string|Array<Statement>}
-   * @param contentType {string}
-   * @param callbackFunction {Function}  callbackFunction(uri, ok, message, response)
-   *
-   * @throws {Error} On unsupported content type (via serialize())
-   *
-   * @returns {Promise}
+   * This is suitable for an initial creation of a document.
    */
-  put (doc, data, contentType, callbackFunction) {
+  put(
+    doc: RDFlibNamedNode,
+    data: string | Quad[],
+    contentType: string,
+    callback: (uri: string, ok: boolean, errorMessage?: string, response?: unknown) => void,
+  ): Promise<void> {
     const kb = this.store
-    let documentString
+    let documentString: string
 
     return Promise.resolve()
       .then(() => {
-        documentString = this.serialize(doc.uri, data, contentType)
+        documentString = this.serialize(doc.value, data, contentType)
 
         return kb.fetcher
-          .webOperation('PUT', doc.uri, { contentType, body: documentString })
+          .webOperation('PUT', doc.value, { contentType, body: documentString })
       })
       .then(response => {
         if (!response.ok) {
-          return callbackFunction(doc.uri, response.ok, response.error, response)
+          return callback(doc.value, response.ok, response.error, response)
         }
 
-        delete kb.fetcher.nonexistent[doc.uri]
-        delete kb.fetcher.requested[doc.uri] // @@ could this mess with the requested state machine? if a fetch is in progress
+        delete kb.fetcher.nonexistent[doc.value]
+        delete kb.fetcher.requested[doc.value] // @@ could this mess with the requested state machine? if a fetch is in progress
 
         if (typeof data !== 'string') {
           data.map((st) => {
@@ -1039,10 +1075,10 @@ export default class UpdateManager {
           })
         }
 
-        callbackFunction(doc.uri, response.ok, '', response)
+        callback(doc.value, response.ok, '', response)
       })
       .catch(err => {
-        callbackFunction(doc.uri, false, err.message)
+        callback(doc.value, false, err.message)
       })
   }
 
@@ -1055,20 +1091,30 @@ export default class UpdateManager {
    * document in the meantime.
    *
    * @param kb
-   * @param doc {NamedNode}
+   * @param doc {RDFlibNamedNode}
    * @param callbackFunction
    */
-  reload (kb, doc, callbackFunction) {
+  reload (
+    kb: IndexedFormula,
+    doc: docReloadType,
+    callbackFunction: (ok: boolean, message?: string, response?: Error | Response) => {} | void
+  ): void {
     var startTime = Date.now()
     // force sets no-cache and
-    const options = { force: true, noMeta: true, clearPreviousData: true }
+    const options = {
+      force: true,
+      noMeta: true,
+      clearPreviousData: true,
+    };
 
-    kb.fetcher.nowOrWhenFetched(doc.uri, options, function (ok, body, response) {
+    (kb as any).fetcher.nowOrWhenFetched(doc.value, options, function (ok: boolean, body: Body, response: Response) {
       if (!ok) {
         console.log('    ERROR reloading data: ' + body)
         callbackFunction(false, 'Error reloading data: ' + body, response)
+        //@ts-ignore Where does onErrorWasCalled come from?
       } else if (response.onErrorWasCalled || response.status !== 200) {
         console.log('    Non-HTTP error reloading data! onErrorWasCalled=' +
+          //@ts-ignore Where does onErrorWasCalled come from?
           response.onErrorWasCalled + ' status: ' + response.status)
         callbackFunction(false, 'Non-HTTP error reloading data: ' + body, response)
       } else {
@@ -1089,3 +1135,8 @@ export default class UpdateManager {
     })
   }
 }
+
+interface docReloadType extends NamedNode {
+  reloadTimeCount?: number
+  reloadTimeTotal?: number
+}
diff --git a/src/updates-via.js b/src/updates-via.js
index 981f54f1f..f56da7b1c 100644
--- a/src/updates-via.js
+++ b/src/updates-via.js
@@ -1,7 +1,7 @@
 /*
  * Updates-Via
  */
-import DataFactory from './data-factory'
+import DataFactory from './factories/rdflib-data-factory'
 
 export class UpdatesSocket {
   constructor (parent, via) {
diff --git a/src/uri.js b/src/uri.ts
similarity index 74%
rename from src/uri.js
rename to src/uri.ts
index 40fe7923b..324f13b8b 100644
--- a/src/uri.js
+++ b/src/uri.ts
@@ -10,10 +10,14 @@
  */
 var alert = alert || console.log
 
-import NamedNode from './named-node'
+import RDFlibNamedNode from './named-node'
 
-export function docpart (uri) {
-  var i
+/**
+ * Gets the document part of an URI
+ * @param uri The URI
+ */
+export function docpart(uri: string): string {
+  var i: number
   i = uri.indexOf('#')
   if (i < 0) {
     return uri
@@ -22,11 +26,19 @@ export function docpart (uri) {
   }
 }
 
-export function document (x) {
-  return new NamedNode(docpart(x.uri))
+/**
+ * Gets the document part of an URI as a named node
+ * @param x - The URI
+ */
+export function document(x: string): RDFlibNamedNode {
+  return new RDFlibNamedNode(docpart(x))
 }
 
-export function hostpart (u) {
+/**
+ * Gets the hostname in an URI
+ * @param u The URI
+ */
+export function hostpart(u: string): string {
   var m = /[^\/]*\/\/([^\/]*)\//.exec(u)
   if (m) {
     return m[1]
@@ -35,7 +47,12 @@ export function hostpart (u) {
   }
 }
 
-export function join (given, base) {
+/**
+ * Joins an URI with a base
+ * @param given - The relative part
+ * @param base - The base URI
+ */
+export function join(given: string, base: string): string {
   var baseColon, baseScheme, baseSingle
   var colon, lastSlash, path
   var baseHash = base.indexOf('#')
@@ -103,9 +120,12 @@ export function join (given, base) {
   return base.slice(0, baseSingle) + path
 }
 
-export function protocol (uri) {
-  var i
-  i = uri.indexOf(':')
+/**
+ * Gets the protocol part of an URI
+ * @param uri The URI
+ */
+export function protocol(uri: string): string | null {
+  const i = uri.indexOf(':')
   if (i < 0) {
     return null
   } else {
@@ -113,8 +133,25 @@ export function protocol (uri) {
   }
 }
 
-export function refTo (base, uri) {
-  var c, i, k, l, len, len1, n, o, p, q, ref, ref1, s
+/**
+ * Gets a relative uri
+ * @param base The base URI
+ * @param uri The absolute URI
+ */
+export function refTo(base: string, uri: string): string {
+  var c: string,
+      i: number,
+      k: number,
+      l: number,
+      len: number,
+      len1: number,
+      n: number,
+      o: number,
+      p: number,
+      q: number,
+      ref: string,
+      ref1: number,
+      s: string
   var commonHost = new RegExp('^[-_a-zA-Z0-9.]+:(//[^/]*)?/[^/]*$')
   if (!base) {
     return uri
@@ -123,7 +160,7 @@ export function refTo (base, uri) {
     return ''
   }
   for (i = o = 0, len = uri.length; o < len; i = ++o) {
-    c = uri[i]
+    const c = uri[i]
     if (c !== base[i]) {
       break
     }
diff --git a/src/util.js b/src/utils-js.js
similarity index 73%
rename from src/util.js
rename to src/utils-js.js
index 0550963ec..eb9b543cb 100644
--- a/src/util.js
+++ b/src/utils-js.js
@@ -20,136 +20,13 @@ export function linkRelationProperty(relation){
   return new NamedNode('http://www.w3.org/ns/iana/link-relations/relation#' + relation.trim())
 }
 
-export const appliedFactoryMethods = [
-  'blankNode',
-  'defaultGraph',
-  'literal',
-  'namedNode',
-  'quad',
-  'variable',
-  'supports',
-]
-
-export function isTerm(obj) {
-  return typeof obj === "object"
-    && obj !== null
-    && "termType" in obj
-    && "value" in obj
-}
-
-export function isStatement(obj) {
-  return typeof obj === "object" && obj !== null && "subject" in obj
-}
-
-export function isStore(obj) {
-  return typeof obj === "object" && obj !== null && "statements" in obj
-}
-
-export function isNamedNode(obj) {
-  return isTerm(obj) && obj.termType === "NamedNode"
-}
-
-/**
- * Loads ontologies of the data we load (this is the callback from the kb to
- * the fetcher).
- */
-export function AJAR_handleNewTerm (kb, p, requestedBy) {
-  var sf = null
-  if (typeof kb.fetcher !== 'undefined') {
-    sf = kb.fetcher
-  } else {
-    return
-  }
-  if (p.termType !== 'NamedNode') return
-  var docuri = docpart(p.uri)
-  var fixuri
-  if (p.uri.indexOf('#') < 0) { // No hash
-    // @@ major hack for dbpedia Categories, which spread indefinitely
-    if (string_startswith(p.uri, 'http://dbpedia.org/resource/Category:')) return
-
-    /*
-      if (string_startswith(p.uri, 'http://xmlns.com/foaf/0.1/')) {
-      fixuri = "http://dig.csail.mit.edu/2005/ajar/ajaw/test/foaf"
-      // should give HTTP 303 to ontology -- now is :-)
-      } else
-    */
-    if (string_startswith(p.uri,
-            'http://purl.org/dc/elements/1.1/') ||
-          string_startswith(p.uri, 'http://purl.org/dc/terms/')) {
-      fixuri = 'http://dublincore.org/2005/06/13/dcq'
-    // dc fetched multiple times
-    } else if (string_startswith(p.uri, 'http://xmlns.com/wot/0.1/')) {
-      fixuri = 'http://xmlns.com/wot/0.1/index.rdf'
-    } else if (string_startswith(p.uri, 'http://web.resource.org/cc/')) {
-      //            log.warn("creative commons links to html instead of rdf. doesn't seem to content-negotiate.")
-      fixuri = 'http://web.resource.org/cc/schema.rdf'
-    }
-  }
-  if (fixuri) {
-    docuri = fixuri
-  }
-  if (sf && sf.getState(docuri) !== 'unrequested') return
-
-  if (fixuri) { // only give warning once: else happens too often
-    log.warn('Assuming server still broken, faking redirect of <' + p.uri +
-      '> to <' + docuri + '>')
-  }
-
-  return sf.fetch(docuri, { referringTerm: requestedBy })
-}
-
-const rdf = {
-  first: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#first',
-  rest: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#rest',
-  nil: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#nil'
-}
-
-/**
- * Expands an array of Terms to a set of statements representing the rdf:list.
- * @param rdfFactory - The factory to use
- * @param {NamedNode|BlankNode} subject - The iri of the first list item.
- * @param {Term[]} data - The terms to expand into the list.
- * @return {Statement[]} - The {data} as a set of statements.
- */
-export function arrayToStatements(rdfFactory, subject, data) {
-  const statements = []
-
-  data.reduce((id, listObj, i, listData) => {
-    statements.push(rdfFactory.quad(id, rdfFactory.namedNode(rdf.first), listData[i]))
-
-    let nextNode
-    if (i < listData.length - 1) {
-      nextNode = rdfFactory.blankNode()
-      statements.push(rdfFactory.quad(id, rdfFactory.namedNode(rdf.rest), nextNode))
-    } else {
-      statements.push(rdfFactory.quad(id, rdfFactory.namedNode(rdf.rest), rdfFactory.namedNode(rdf.nil)))
-    }
-
-    return nextNode
-  }, subject)
-
-  return statements
-}
-
-export function ArrayIndexOf (arr, item, i) {
-  i || (i = 0)
-  var length = arr.length
-  if (i < 0) i = length + i
-  for (; i < length; i++) {
-    if (arr[i] === item) {
-      return i
-    }
-  }
-  return -1
-}
-
 /**
  * Adds callback functionality to an object.
  * Callback functions are indexed by a 'hook' string.
  * They return true if they want to be called again.
  * @method callbackify
  * @param obj {Object}
- * @param callbacks {Array<Function>}
+ * @param callbacks {Array<string>}
  */
 export function callbackify (obj, callbacks) {
   obj.callbacks = {}
diff --git a/src/utils.ts b/src/utils.ts
new file mode 100644
index 000000000..c5eac100e
--- /dev/null
+++ b/src/utils.ts
@@ -0,0 +1,114 @@
+import Fetcher from './fetcher'
+import log from './log'
+import { docpart } from './uri'
+import { string_startswith } from './utils-js'
+import { RdfJsDataFactory, Quad, Quad_Subject, Term } from './tf-types'
+
+/** RDF/JS spec Typeguards */
+
+/**
+ * Loads ontologies of the data we load (this is the callback from the kb to
+ * the fetcher).
+ */
+export function AJAR_handleNewTerm (kb: { fetcher: Fetcher }, p, requestedBy) {
+  var sf: Fetcher | null = null
+  if (typeof kb.fetcher !== 'undefined') {
+    sf = kb.fetcher
+  } else {
+    return
+  }
+  if (p.termType !== 'NamedNode') return
+  var docuri = docpart(p.uri)
+  var fixuri
+  if (p.uri.indexOf('#') < 0) { // No hash
+    // @@ major hack for dbpedia Categories, which spread indefinitely
+    if (string_startswith(p.uri, 'http://dbpedia.org/resource/Category:')) return
+
+    /*
+      if (string_startswith(p.uri, 'http://xmlns.com/foaf/0.1/')) {
+      fixuri = "http://dig.csail.mit.edu/2005/ajar/ajaw/test/foaf"
+      // should give HTTP 303 to ontology -- now is :-)
+      } else
+    */
+    if (string_startswith(p.uri,
+            'http://purl.org/dc/elements/1.1/') ||
+          string_startswith(p.uri, 'http://purl.org/dc/terms/')) {
+      fixuri = 'http://dublincore.org/2005/06/13/dcq'
+    // dc fetched multiple times
+    } else if (string_startswith(p.uri, 'http://xmlns.com/wot/0.1/')) {
+      fixuri = 'http://xmlns.com/wot/0.1/index.rdf'
+    } else if (string_startswith(p.uri, 'http://web.resource.org/cc/')) {
+      //            log.warn("creative commons links to html instead of rdf. doesn't seem to content-negotiate.")
+      fixuri = 'http://web.resource.org/cc/schema.rdf'
+    }
+  }
+  if (fixuri) {
+    docuri = fixuri
+  }
+  if (sf && (sf as Fetcher).getState(docuri) !== 'unrequested') return
+
+  if (fixuri) { // only give warning once: else happens too often
+    log.warn('Assuming server still broken, faking redirect of <' + p.uri +
+      '> to <' + docuri + '>')
+  }
+
+  return (sf as any).fetch(docuri, { referringTerm: requestedBy })
+}
+
+export const appliedFactoryMethods = [
+  'blankNode',
+  'defaultGraph',
+  'literal',
+  'namedNode',
+  'quad',
+  'variable',
+  'supports',
+]
+
+const rdf = {
+  first: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#first',
+  rest: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#rest',
+  nil: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#nil'
+}
+
+/**
+ * Expands an array of Terms to a set of statements representing the rdf:list.
+ * @param rdfFactory - The factory to use
+ * @param subject - The iri of the first list item.
+ * @param data - The terms to expand into the list.
+ * @return The {data} as a set of statements.
+ */
+export function arrayToStatements(
+  rdfFactory: RdfJsDataFactory,
+  subject: Quad_Subject,
+  data: Term[]
+): Quad[] {
+  const statements: Quad[] = []
+
+  data.reduce<Quad_Subject>((id, _listObj, i, listData) => {
+    statements.push(rdfFactory.quad(id, rdfFactory.namedNode(rdf.first), listData[i]))
+
+    let nextNode
+    if (i < listData.length - 1) {
+      nextNode = rdfFactory.blankNode()
+      statements.push(rdfFactory.quad(id, rdfFactory.namedNode(rdf.rest), nextNode))
+    } else {
+      statements.push(rdfFactory.quad(id, rdfFactory.namedNode(rdf.rest), rdfFactory.namedNode(rdf.nil)))
+    }
+
+    return nextNode
+  }, subject)
+
+  return statements
+}
+
+export function ArrayIndexOf (arr, item, i: number = 0) {
+  var length = arr.length
+  if (i < 0) i = length + i
+  for (; i < length; i++) {
+    if (arr[i] === item) {
+      return i
+    }
+  }
+  return -1
+}
diff --git a/src/utils/default-graph-uri.ts b/src/utils/default-graph-uri.ts
new file mode 100644
index 000000000..6186956c8
--- /dev/null
+++ b/src/utils/default-graph-uri.ts
@@ -0,0 +1,6 @@
+// Prevents circular dependencies between data-factory-internal and statement
+
+import NamedNode from '../named-node'
+
+export const defaultGraphURI = 'chrome:theSession'
+export const defaultGraphNode = new NamedNode(defaultGraphURI)
diff --git a/src/utils/termValue.ts b/src/utils/termValue.ts
new file mode 100644
index 000000000..43d5630cf
--- /dev/null
+++ b/src/utils/termValue.ts
@@ -0,0 +1,10 @@
+import { Term } from '../tf-types'
+
+/** Retrieve the value of a term, or self if already a string. */
+export function termValue (node: Term | string): string {
+  if (typeof node === 'string') {
+    return node
+  }
+
+  return node.value
+}
diff --git a/src/utils/terms.ts b/src/utils/terms.ts
new file mode 100644
index 000000000..b51871747
--- /dev/null
+++ b/src/utils/terms.ts
@@ -0,0 +1,119 @@
+import {
+  ObjectType, CollectionTermType, NamedNodeTermType, VariableTermType, BlankNodeTermType, LiteralTermType, DefaultGraphTermType,
+} from '../types'
+import Collection from '../collection'
+import IndexedFormula from '../store'
+import Statement from '../statement'
+import {
+  BlankNode,
+  Quad_Graph,
+  Literal,
+  NamedNode,
+  Quad_Object,
+  Quad_Predicate,
+  Quad,
+  Quad_Subject,
+  Term,
+  Variable,
+} from '../tf-types'
+
+/** TypeGuard for RDFLib Statements */
+export function isStatement(obj): obj is Statement {
+  return typeof obj === 'object' && obj !== null && 'subject' in obj
+}
+
+/** TypeGuard for RDFlib Stores */
+export function isStore(obj): obj is IndexedFormula {
+  return typeof obj === 'object' && obj !== null && 'statements' in obj
+}
+
+/** TypeGuard for RDFLib Collections */
+export function isCollection(obj: any): obj is Collection<any> {
+  return isTerm(obj)
+    && (obj as Term).termType === CollectionTermType
+}
+
+/** TypeGuard for valid RDFlib Object types, also allows Collections */
+export function isRDFlibObject(obj: any): obj is ObjectType {
+  return obj && Object.prototype.hasOwnProperty.call(obj, 'termType') && (
+    obj.termType === NamedNodeTermType ||
+    obj.termType === VariableTermType ||
+    obj.termType === BlankNodeTermType ||
+    obj.termType === CollectionTermType ||
+    obj.termType === LiteralTermType
+  )
+}
+
+/** TypeGuard for RDFLib Variables */
+export function isVariable(obj: any): obj is Variable {
+  return isTerm(obj)
+    && (obj as Term).termType === VariableTermType
+}
+
+/** TypeGuard for RDF/JS spec Terms */
+export function isTerm(obj: any): obj is Term {
+  return typeof obj === 'object'
+    && obj !== null
+    && 'termType' in obj
+}
+
+/** TypeGuard for RDF/JS spec Literals */
+export function isLiteral(value: any): value is Literal {
+  return (value as Term).termType === LiteralTermType
+}
+
+/** TypeGuard for RDF/JS spec Quads */
+export function isQuad(obj: any): obj is Quad<any, any, any, any> {
+  return typeof obj === "object" && obj !== null && (
+    'subject' in obj
+    && 'predicate' in obj
+    && 'object' in obj
+  )
+}
+
+/** TypeGuard for RDF/JS spec NamedNodes */
+export function isNamedNode(obj: any): obj is NamedNode {
+  return isTerm(obj) && obj.termType === 'NamedNode'
+}
+
+/** TypeGuard for RDF/JS spec BlankNodes */
+export function isBlankNode(obj: any): obj is BlankNode {
+  return isTerm(obj) && 'termType' in obj && obj.termType === 'BlankNode'
+}
+
+/** TypeGuard for valid RDF/JS spec Subject types */
+export function isSubject(obj: any): obj is Quad_Subject {
+  return isTerm(obj) && (
+    obj.termType === NamedNodeTermType ||
+    obj.termType === VariableTermType ||
+    obj.termType === BlankNodeTermType
+  )
+}
+
+/** TypeGuard for valid RDF/JS spec Predicate types */
+export function isPredicate(obj: any): obj is Quad_Predicate {
+  return isTerm(obj) && (
+    obj.termType === NamedNodeTermType ||
+    obj.termType === VariableTermType
+  )
+}
+
+/** TypeGuard for valid RDF/JS spec Object types */
+export function isRDFObject(obj: any): obj is Quad_Object {
+  return isTerm(obj) && (
+    obj.termType === NamedNodeTermType ||
+    obj.termType === VariableTermType ||
+    obj.termType === BlankNodeTermType ||
+    obj.termType === LiteralTermType
+  )
+}
+
+/** TypeGuard for valid RDF/JS Graph types */
+export function isGraph(obj: any): obj is Quad_Graph {
+  return isTerm(obj) && (
+    obj.termType === NamedNodeTermType ||
+    obj.termType === VariableTermType ||
+    obj.termType === BlankNodeTermType ||
+    obj.termType === DefaultGraphTermType
+  )
+}
diff --git a/src/variable.js b/src/variable.js
deleted file mode 100644
index 65d199e1f..000000000
--- a/src/variable.js
+++ /dev/null
@@ -1,48 +0,0 @@
-'use strict'
-import ClassOrder from './class-order'
-import Node from './node'
-import * as Uri from './uri'
-
-/**
- * Variables are placeholders used in patterns to be matched.
- * In cwm they are symbols which are the formula's list of quantified variables.
- * In sparql they are not visibly URIs.  Here we compromise, by having
- * a common special base URI for variables. Their names are uris,
- * but the ? notation has an implicit base uri of 'varid:'
- * @class Variable
- */
-export default class Variable extends Node {
-  constructor (name = '') {
-    super()
-    this.termType = Variable.termType
-    this.value = name
-    this.base = 'varid:'
-    this.uri = Uri.join(name, this.base)
-  }
-  equals (other) {
-    if (!other) {
-      return false
-    }
-    return (this.termType === other.termType) && (this.value === other.value)
-  }
-  hashString () {
-    return this.toString()
-  }
-  substitute (bindings) {
-    var ref
-    return (ref = bindings[this.toNT()]) != null ? ref : this
-  }
-  toString () {
-    return Variable.toString(this)
-  }
-  static toString (variable) {
-    if (variable.uri.slice(0, variable.base.length) === variable.base) {
-      return '?' + variable.uri.slice(variable.base.length)
-    }
-    return '?' + variable.uri
-  }
-}
-
-Variable.termType = 'Variable'
-Variable.prototype.classOrder = ClassOrder['Variable']
-Variable.prototype.isVar = 1
diff --git a/src/variable.ts b/src/variable.ts
new file mode 100644
index 000000000..03de55c54
--- /dev/null
+++ b/src/variable.ts
@@ -0,0 +1,62 @@
+import ClassOrder from './class-order'
+import Node from './node-internal'
+import { VariableTermType } from './types'
+import * as Uri from './uri'
+import { Variable as TFVariable } from './tf-types'
+
+/**
+* Variables are placeholders used in patterns to be matched.
+* In cwm they are symbols which are the formula's list of quantified variables.
+* In sparql they are not visibly URIs.  Here we compromise, by having
+* a common special base URI for variables. Their names are uris,
+* but the ? notation has an implicit base uri of 'varid:'
+*/
+export default class Variable extends Node implements TFVariable {
+  termType: typeof VariableTermType = VariableTermType
+
+  /** The base string for a variable's name */
+  base = 'varid:'
+  classOrder = ClassOrder.Variable
+  isVar = 1
+  /** The unique identifier of this variable */
+  uri: string
+
+  /**
+   * Initializes this variable
+   * @param name The variable's name
+   */
+  constructor (name = '') {
+    super(name)
+    this.base = 'varid:'
+    this.uri = Uri.join(name, this.base)
+  }
+
+  equals (other) {
+    if (!other) {
+      return false
+    }
+
+    return (this.termType === other.termType) && (this.value === other.value)
+  }
+
+  hashString () {
+    return this.toString()
+  }
+
+  substitute (bindings) {
+    var ref
+    return (ref = bindings[this.toNT()]) != null ? ref : this
+  }
+
+  toString () {
+    return Variable.toString(this)
+  }
+
+  static toString (variable) {
+    if (variable.uri.slice(0, variable.base.length) === variable.base) {
+      return `?${variable.uri.slice(variable.base.length)}`
+    }
+
+    return `?${variable.uri}`
+  }
+}
diff --git a/src/xsd.js b/src/xsd.js
index 8e852ca22..814c5cc16 100644
--- a/src/xsd.js
+++ b/src/xsd.js
@@ -1,4 +1,4 @@
-import CanonicalDataFactory from './data-factory-internal'
+import CanonicalDataFactory from './factories/canonical-data-factory'
 
 export function createXSD(localFactory = CanonicalDataFactory) {
   class XSD {}
diff --git a/tests/unit/factories/canonical-data-factory-test.ts b/tests/unit/factories/canonical-data-factory-test.ts
new file mode 100644
index 000000000..d0cc69818
--- /dev/null
+++ b/tests/unit/factories/canonical-data-factory-test.ts
@@ -0,0 +1,65 @@
+import { expect } from 'chai'
+
+import Factory from '../../../src/factories/canonical-data-factory';
+import { Feature } from '../../../src/factories/factory-types'
+import NamedNode from '../../../src/named-node'
+import Literal from '../../../src/literal'
+import DefaultGraph from '../../../src/default-graph'
+import Empty from '../../../src/empty'
+
+describe('data-factory', () => {
+  it('supports id', () => { expect(Factory.supports[Feature.id]).to.be.true() })
+  it('supports equalsMethod', () => { expect(Factory.supports[Feature.equalsMethod]).to.be.true() })
+  it('does not supports collections', () => { expect(Factory.supports[Feature.collections]).to.be.false() })
+  it('does not supports defaultGraphType', () => { expect(Factory.supports[Feature.defaultGraphType]).to.be.false() })
+  it('does not supports identity', () => { expect(Factory.supports[Feature.identity]).to.be.false() })
+  it('does not supports reversibleId', () => { expect(Factory.supports[Feature.reversibleId]).to.be.false() })
+
+  describe('equals', () => {
+    const uri = "https://w3.org/"
+    const otherUri = "https://h3h3.org/"
+    it('handles same NamedNodes', () => expect(Factory.namedNode(uri).equals(Factory.namedNode(uri))).to.be.true)
+    it('handles different NamedNodes', () => expect(Factory.namedNode(uri).equals(Factory.namedNode(otherUri))).to.be.false)
+  });
+
+  describe('id', () => {
+    it('handles default graph', () => expect(Factory.id(new DefaultGraph())).to.equal('defaultGraph'))
+  });
+
+  describe('isQuad', () => {});
+
+  describe('literal', () => {
+    const plain = Factory.literal('s')
+    it('keeps the value', () => expect(plain.value).to.equal('s'))
+    it('creates a literal', () => expect(plain).to.be.instanceOf(Literal))
+    it('defaults to string', () => expect(plain.datatype.value).to.equal('http://www.w3.org/2001/XMLSchema#string'))
+
+    const integer = Factory.literal('23', Factory.namedNode('http://www.w3.org/2001/XMLSchema#integer'))
+    it('keeps the datatype', () => expect(integer.datatype.value).to.equal('http://www.w3.org/2001/XMLSchema#integer'))
+
+    const langString = Factory.literal('s', 'en')
+    it('sets a language', () => expect(langString.language).to.equal('en'))
+    it('sets a language', () => expect(langString.datatype.value).to.equal('http://www.w3.org/1999/02/22-rdf-syntax-ns#langString'))
+  });
+
+  describe('namedNode', () => {
+    it('creates a named node', () => expect(Factory.namedNode('about:config')).to.be.instanceOf(NamedNode))
+    it('preserves the value', () => expect(Factory.blankNode('http://example.com/').value).to.equal('http://example.com/'))
+  });
+
+  describe('quad', () => {});
+
+  describe('quadToNQ', () => {});
+
+  describe('termToNQ', () => {
+    it('handles blank nodes', () => expect(Factory.termToNQ(Factory.blankNode('g123'))).to.equal('_:g123'))
+    it('handles default graph', () => expect(Factory.termToNQ(new DefaultGraph())).to.equal(''))
+    it('handles the empty collection', () => expect(Factory.termToNQ(new Empty())).to.equal('<http://www.w3.org/1999/02/22-rdf-syntax-ns#nil>'))
+    it('handles literals', () => expect(Factory.termToNQ(Factory.literal('text with "quotes"'))).to.equal('"text with \\"quotes\\""'))
+    it('handles named nodes', () => expect(Factory.termToNQ(Factory.namedNode('http://example.com/'))).to.equal('<http://example.com/>'))
+  });
+
+  describe('toNQ', () => {});
+
+  describe('variable', () => {});
+})
diff --git a/tests/unit/factories/extended-term-factory-test.ts b/tests/unit/factories/extended-term-factory-test.ts
new file mode 100644
index 000000000..b886b2cf9
--- /dev/null
+++ b/tests/unit/factories/extended-term-factory-test.ts
@@ -0,0 +1,35 @@
+import { expect } from 'chai'
+
+import Factory from '../../../src/factories/extended-term-factory';
+import { Feature } from '../../../src/factories/factory-types'
+import Collection from '../../../src/collection'
+
+/**
+ * @ignore
+ * Inherits from CanonicalDataFactory (internal), so we only have to test the added features
+ * e.g. Collection
+ */
+describe('extended-term-factory', () => {
+  it('supports collections', () => { expect(Factory.supports[Feature.collections]).to.be.true() })
+  it('supports equalsMethod', () => { expect(Factory.supports[Feature.equalsMethod]).to.be.true() })
+  it('supports id', () => { expect(Factory.supports[Feature.id]).to.be.true() })
+  it('does not supports identity', () => { expect(Factory.supports[Feature.identity]).to.be.false() })
+  it('does not supports defaultGraphType', () => { expect(Factory.supports[Feature.defaultGraphType]).to.be.false() })
+  it('does not supports reversibleId', () => { expect(Factory.supports[Feature.reversibleId]).to.be.false() })
+
+  describe('id', () => {
+    it('handles collections', () => {
+      expect(Factory.id(new Collection([
+        Factory.literal('1'),
+        Factory.namedNode('http://example.com/'),
+      ]))).to.equal('( "1", <http://example.com/> )')
+    })
+  })
+
+  describe('termToNQ', () => {
+    it('handles collections', () => {
+      const c = new Collection([ '1', '2' ])
+      expect(Factory.termToNQ(c)).to.equal(`_:${c.id}`)
+    })
+  });
+})
diff --git a/tests/unit/fetcher-egp-test.js b/tests/unit/fetcher-egp-test.js
index 7e38a3b69..05e20277b 100644
--- a/tests/unit/fetcher-egp-test.js
+++ b/tests/unit/fetcher-egp-test.js
@@ -22,7 +22,7 @@ describe('Fetcher', () => {
       let kb = rdf.graph();
       let fetcher = rdf.fetcher(kb, {a:1})
       fetcher.nowOrWhenFetched(kb.sym(goodServer + path), {force: true}, trywrap(done, function (ok, statusOrErrorText, resp) {
-        expect(ok).to.be.true
+        expect(ok).to.be.true()
         expect(resp.status).to.equal(200)
         expect(statusOrErrorText).to.equal('OK')
         expect(resp.responseText.length).to.equal(bodyText.length)
@@ -51,7 +51,7 @@ describe('Fetcher', () => {
         console.log('@@@@@@ resp is ' + resp)
         console.log('@@@@@@ resp.status is ' + resp.status)
 
-        expect(ok).to.be.false
+        expect(ok).to.be.false()
         expect(statusOrErrorText).to.include(404)
         expect(resp.status).to.match(/404/)
       }))
@@ -64,7 +64,7 @@ describe('Fetcher', () => {
       let kb = rdf.graph();
       let fetcher = rdf.fetcher(kb, {a:1})
       fetcher.nowOrWhenFetched(kb.sym(badServer + path), {force: true}, trywrap(done, function (ok, statusOrErrorText, resp) {
-        expect(ok).to.be.false
+        expect(ok).to.be.false()
         expect(statusOrErrorText).to.match(/ENOTFOUND/);
         expect(resp.status).to.equal(999)
       }))
diff --git a/tests/unit/fetcher-test.js b/tests/unit/fetcher-test.js
index 182c0942b..f9b66dfe9 100644
--- a/tests/unit/fetcher-test.js
+++ b/tests/unit/fetcher-test.js
@@ -10,7 +10,7 @@ import nock from 'nock'
 import * as rdf from '../../src/index'
 import NamedNode from '../../src/named-node'
 import IndexedFormula from '../../src/store'
-import CanonicalDataFactory from '../../src/data-factory-internal'
+import CanonicalDataFactory from '../../src/factories/canonical-data-factory'
 
 chai.use(sinonChai)
 chai.use(dirtyChai)
@@ -46,7 +46,7 @@ describe('Fetcher', () => {
       }
       let fetcher = new Fetcher()
 
-      expect(fetcher.store.fetcher === fetcher).to.be.true
+      expect(fetcher.store.fetcher === fetcher).to.be.true()
     })
   })
 
@@ -70,6 +70,7 @@ describe('Fetcher', () => {
         status: 200,
       })
       const options = {
+        req: store.rdfFactory.blankNode(),
         resource: store.rdfFactory.namedNode('https://example.com/resource/1')
       }
 
diff --git a/tests/unit/indexed-formula-test.js b/tests/unit/indexed-formula-test.js
index 0bc02ca39..d95d1cf77 100644
--- a/tests/unit/indexed-formula-test.js
+++ b/tests/unit/indexed-formula-test.js
@@ -1,12 +1,12 @@
 /* eslint-env mocha */
 import { expect } from 'chai'
-import CanonicalDataFactory from '../../src/data-factory-internal'
+import CanonicalDataFactory from '../../src/factories/canonical-data-factory'
 import Formula from '../../src/formula'
 
 import IndexedFormula from '../../src/store'
 import NamedNode from '../../src/named-node'
-import DataFactory from '../../src/data-factory'
-import { RDFArrayRemove } from '../../src/util'
+import { RDFArrayRemove } from '../../src/utils-js'
+import DataFactory from '../../src/factories/rdflib-data-factory'
 
 describe('IndexedFormula', () => {
   const g0 = NamedNode.fromValue('https://example.com/graph0')
diff --git a/tests/unit/literal-test.js b/tests/unit/literal-test.js
index 1529e3e20..6bf09db3a 100644
--- a/tests/unit/literal-test.js
+++ b/tests/unit/literal-test.js
@@ -104,17 +104,17 @@ describe('Literal', () => {
     it('compares termType, value, language, and datatype', () => {
       const a = new Literal('hello world', 'en', XSD.langString)
       const b = new Literal('', '', null)
-      expect(a.equals(b)).to.be.false
-      expect(b.equals(a)).to.be.false
+      expect(a.equals(b)).to.be.false()
+      expect(b.equals(a)).to.be.false()
       b.value = 'hello world'
-      expect(a.equals(b)).to.be.false
-      expect(b.equals(a)).to.be.false
+      expect(a.equals(b)).to.be.false()
+      expect(b.equals(a)).to.be.false()
       b.language = 'en'
-      expect(a.equals(b)).to.be.false
-      expect(b.equals(a)).to.be.false
+      expect(a.equals(b)).to.be.false()
+      expect(b.equals(a)).to.be.false()
       b.datatype = XSD.langString
-      expect(a.equals(b)).to.be.true
-      expect(b.equals(a)).to.be.true
+      expect(a.equals(b)).to.be.true()
+      expect(b.equals(a)).to.be.true()
     })
   })
 })
diff --git a/tests/unit/parse-test.js b/tests/unit/parse-test.js
index 9ffb399bd..6cacdc9fe 100644
--- a/tests/unit/parse-test.js
+++ b/tests/unit/parse-test.js
@@ -2,10 +2,9 @@
 import { expect } from 'chai'
 
 import parse from '../../src/parse'
-import CanonicalDataFactory from '../../src/data-factory-internal'
-import DataFactory from '../../src/data-factory'
-import Node from '../../src/node'
+import CanonicalDataFactory from '../../src/factories/canonical-data-factory'
 import defaultXSD from '../../src/xsd'
+import DataFactory from '../../src/factories/rdflib-data-factory'
 
 describe('Parse', () => {
   describe('ttl', () => {
@@ -114,7 +113,7 @@ describe('Parse', () => {
       })
 
       it('uses the specified base IRI', () => {
-        expect(store.rdfFactory.supports["COLLECTIONS"]).to.be.false
+        expect(store.rdfFactory.supports["COLLECTIONS"]).to.be.false()
         const homePageHeight = 5 // homepage + height + 3 x name
         const list = 2 * 3 + 1 // (rdf:first + rdf:rest) * 3 items + listProp
         expect(store.statements).to.have.length(homePageHeight + list)
@@ -208,7 +207,7 @@ describe('Parse', () => {
       })
 
       it('uses the specified base IRI', () => {
-        expect(store.rdfFactory.supports["COLLECTIONS"]).to.be.true
+        expect(store.rdfFactory.supports["COLLECTIONS"]).to.be.true()
         expect(store.statements).to.have.length(1)
 
         const collection = store.statements[0]
diff --git a/tests/unit/query-test.js b/tests/unit/query-test.js
index 443eeaa23..e0baf969e 100644
--- a/tests/unit/query-test.js
+++ b/tests/unit/query-test.js
@@ -189,8 +189,8 @@ describe('Query', () => {
         result[(bindings['?x'].value)] = true
       }, null, () => { // fetcher, done callback
         result.sort()
-        expect(result[alice.uri]).to.be.true
-        expect(result[bob.uri]).to.be.true
+        expect(result[alice.uri]).to.be.true()
+        expect(result[bob.uri]).to.be.true()
         done()
       })
     })
@@ -365,8 +365,8 @@ describe('Synchronous Query', () => {
         result[(bindings['?x'].value)] = true
       }, null, () => { // fetcher, done callback
         result.sort()
-        expect(result[alice.uri]).to.be.true
-        expect(result[bob.uri]).to.be.true
+        expect(result[alice.uri]).to.be.true()
+        expect(result[bob.uri]).to.be.true()
         done()
       })
     })
diff --git a/tests/unit/typings-test.ts b/tests/unit/typings-test.ts
new file mode 100644
index 000000000..e76ce8160
--- /dev/null
+++ b/tests/unit/typings-test.ts
@@ -0,0 +1,18 @@
+
+import Statement from '../../src/statement'
+import Literal from '../../src/literal'
+import { expect } from 'chai'
+
+/**
+ * These test do some assertions, but their main test is that they don't create compiler errors.
+ */
+describe('typings', () => {
+  it('allows calling Literal.equal with non-literal', () => {
+    const test = (): Statement => ({}) as unknown as Statement
+
+    const b = test()
+    const c = new Literal("")
+
+    expect(c.equals(b.object)).to.be.false()
+  })
+})
diff --git a/tests/unit/util-test.js b/tests/unit/util-test.js
index 697ead171..b51bc73e5 100644
--- a/tests/unit/util-test.js
+++ b/tests/unit/util-test.js
@@ -1,32 +1,57 @@
 /* eslint-env mocha */
 import { expect } from 'chai'
 
-import CanonicalDataFactory from '../../src/data-factory-internal'
+import CanonicalDataFactory from '../../src/factories/canonical-data-factory'
 import Literal from '../../src/literal'
 import NamedNode from '../../src/named-node'
 import Statement from '../../src/statement'
-import { arrayToStatements, isNamedNode, isStatement, isTerm } from '../../src/util'
+import { arrayToStatements } from '../../src/utils'
+import {
+  isBlankNode,
+  isCollection,
+  isNamedNode,
+  isQuad,
+  isRDFlibObject,
+  isRDFObject,
+  isStatement,
+  isStore,
+  isTerm,
+  isVariable,
+  isLiteral,
+} from '../../src/utils/terms'
+import IndexedFormula from '../../src/store'
+import BlankNode from '../../src/blank-node'
+import Collection from '../../src/collection'
+import Variable from '../../src/variable'
 
 describe('util', () => {
   describe('isTerm', () => {
     it('handles undefined', () => {
-      expect(isNamedNode(undefined)).to.be.false()
+      expect(isTerm(undefined)).to.be.false()
     })
 
     it('handles null', () => {
-      expect(isNamedNode(null)).to.be.false()
+      expect(isTerm(null)).to.be.false()
     })
 
     it('handles other objects', () => {
-      expect(isNamedNode(1)).to.be.false()
-      expect(isNamedNode(true)).to.be.false()
-      expect(isNamedNode(NaN)).to.be.false()
-      expect(isNamedNode({})).to.be.false()
+      expect(isTerm(1)).to.be.false()
+      expect(isTerm(true)).to.be.false()
+      expect(isTerm(NaN)).to.be.false()
+      expect(isTerm({})).to.be.false()
     })
 
-    it ('handles literals', () => {
+    it('handles literals', () => {
       expect(isTerm(new Literal('test'))).to.be.true()
     });
+
+    it('handles namedNodes', () => {
+      expect(isTerm(new NamedNode('https://example.com/test'))).to.be.true()
+    });
+
+    it('handles blankNodes', () => {
+      expect(isTerm(new BlankNode('test'))).to.be.true()
+    });
   })
 
   describe('isNamedNode', () => {
@@ -43,16 +68,185 @@ describe('util', () => {
       expect(isNamedNode(new NamedNode('http://example.org/'))).to.be.true()
     })
 
+    it('handles Literal instances', () => {
+      expect(isNamedNode(new Literal('http://example.org/'))).to.be.false()
+    })
+
+    it('handles plain objects', () => {
+      expect(isNamedNode({ termType: 'NamedNode', value: '' })).to.be.true()
+    })
+
+    it('handles prototype based objects', () => {
+      const proto = {
+        termType: 'NamedNode'
+      }
+      const obj = Object.create(proto)
+      obj.value = ''
+      expect(isNamedNode(obj)).to.be.true()
+    })
+
     it('handles plain objects', () => {
       expect(isNamedNode({ termType: 'NamedNode', value: '' })).to.be.true()
     })
   })
 
   describe('isStatement', () => {
-    it ('handles Statement objects', () => {
+    it('handles Statement objects', () => {
       const t = new NamedNode('http://example.org')
       expect(isStatement(new Statement(t, t, t))).to.be.true()
     })
+
+    it('handles other objects', () => {
+      const t = new NamedNode('http://example.org')
+      expect(isStatement(t)).to.be.false()
+    })
+  })
+
+  describe('isStore', () => {
+    it('handles IndexedFormula objects', () => {
+      const t = new IndexedFormula()
+      expect(isStore(t)).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      expect(isStore(NaN)).to.be.false()
+    })
+  })
+
+  describe('isCollection', () => {
+    it('handles Collection objects', () => {
+      const t = new Collection()
+      expect(isCollection(t)).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      const t = new NamedNode('http://example.org')
+      expect(isCollection(t)).to.be.false()
+    })
+  })
+
+  describe('isRDFlibObject', () => {
+    it('handles Collection objects', () => {
+      const t = new Collection()
+      expect(isRDFlibObject(t)).to.be.true()
+    })
+
+    it('handles NamedNode objects', () => {
+      const t = new NamedNode('http://example.org')
+      expect(isRDFlibObject(t)).to.be.true()
+    })
+
+    it('handles Variable objects', () => {
+      const t = new Variable()
+      expect(isRDFlibObject(t)).to.be.true()
+    })
+
+    it('handles BlankNode objects', () => {
+      const t = new BlankNode()
+      expect(isRDFlibObject(t)).to.be.true()
+    })
+
+    it('handles Literal objects', () => {
+      const t = new Literal()
+      expect(isRDFlibObject(t)).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      const t = {
+        some: "object"
+      }
+      expect(isRDFlibObject(t)).to.be.false()
+    })
+  })
+
+  describe('isVariable', () => {
+    it('handles Variable objects', () => {
+      const t = new Variable()
+      expect(isVariable(t)).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      const t = new NamedNode('http://example.org')
+      expect(isVariable(t)).to.be.false()
+      expect(isVariable(undefined)).to.be.false()
+      expect(isVariable(2)).to.be.false()
+    })
+  })
+
+  describe('isLiteral', () => {
+    it('handles Literal objects', () => {
+      const t = new Literal()
+      expect(isLiteral(t)).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      const nn = new NamedNode('http://example.org')
+      expect(isLiteral(nn)).to.be.false()
+      const v = new Variable('http://example.org')
+      expect(isLiteral(v)).to.be.false()
+      const bn = new BlankNode('http://example.org')
+      expect(isLiteral(bn)).to.be.false()
+    })
+  })
+
+  describe('isQuad', () => {
+    it('handles Statement objects', () => {
+      const t = new NamedNode('http://example.org')
+      expect(isQuad(new Statement(t, t, t))).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      const nn = new NamedNode('http://example.org')
+      expect(isQuad(nn)).to.be.false()
+      const v = new Variable('http://example.org')
+      expect(isQuad(v)).to.be.false()
+      const bn = new BlankNode('http://example.org')
+      expect(isQuad(bn)).to.be.false()
+    })
+  })
+
+  describe('isBlankNode', () => {
+    it('handles BlankNode objects', () => {
+      const t = new BlankNode()
+      expect(isBlankNode(t)).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      const nn = new NamedNode('http://example.org')
+      expect(isBlankNode(nn)).to.be.false()
+      const v = new Variable('http://example.org')
+      expect(isBlankNode(v)).to.be.false()
+      const bn = new Literal('http://example.org')
+      expect(isBlankNode(bn)).to.be.false()
+    })
+  })
+
+  describe('isObject', () => {
+    it('handles BlankNode objects', () => {
+      const t = new BlankNode()
+      expect(isRDFObject(t)).to.be.true()
+    })
+
+    it('handles Variable objects', () => {
+      const t = new Variable()
+      expect(isRDFObject(t)).to.be.true()
+    })
+
+    it('handles Literal objects', () => {
+      const t = new Literal()
+      expect(isRDFObject(t)).to.be.true()
+    })
+
+    it('handles NamedNode objects', () => {
+      const t = new NamedNode("https://someurl.com")
+      expect(isRDFObject(t)).to.be.true()
+    })
+
+    it('handles other objects', () => {
+      expect(isRDFObject(2)).to.be.false()
+      expect(isRDFObject({})).to.be.false()
+      expect(isRDFObject(undefined)).to.be.false()
+    })
   })
 
   describe('arrayToStatements', () => {
diff --git a/tsconfig.json b/tsconfig.json
index 4b78c20c4..485ae3d98 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -3,13 +3,16 @@
     "allowSyntheticDefaultImports": true,
     "checkJs": false,
     "allowJs": true,
-    "target": "es6",
-    "module": "es6",
+    "target": "es2019",
+    "module": "esnext",
     "strict": true,
     "noImplicitAny": false,
+    "noUnusedLocals": true,
     "lib": [
-      "es2019"
-    ]
+      "es2019",
+      "dom"
+    ],
+    "outDir": "./temp_ts_output"
   },
   "include": [
     "src/**/*"
diff --git a/typedoc.js b/typedoc.js
new file mode 100644
index 000000000..c3592bae5
--- /dev/null
+++ b/typedoc.js
@@ -0,0 +1,18 @@
+module.exports = {
+  src: ['./src'],
+  mode: "file",
+  out: "doc",
+  tsconfig: "tsconfig.json",
+  theme: "default",
+  hideGenerator: true,
+  ignoreCompilerErrors: true,
+  excludePrivate: true,
+  excludeNotExported: "true",
+  target: "ES6",
+  moduleResolution: "node",
+  preserveConstEnums: "true",
+  stripInternal: "true",
+  suppressExcessPropertyErrors: "true",
+  suppressImplicitAnyIndexErrors: "true",
+  module: "commonjs"
+}
diff --git a/webpack.config.js b/webpack.config.js
index 5198dab44..5d76939a2 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -26,6 +26,7 @@ module.exports = (env, args) => {
         }
       ]
     },
+    resolve: { extensions: ['.js', '.ts'] },
     plugins: [
       new WrapperPlugin({
         // Fall back to window.fetch when solid-auth-client is not present,