Merge branch 'lindsvg-1.1.0'

.eslintignore

@@ -1 +1,2 @@
-dist/
+dist/
+test/

README.md

@@ -78,6 +78,25 @@ let {pathData, minX, minY, width, height} = getSVGData(lsParams);
 
 An object returned by `getSVGData` contains [path data](https://www.w3.org/TR/SVG11/paths.html#PathData) needed to draw the L-system, and also the drawing boundaries that are essential for the `viewBox` attribute.
 
+In case of invalid input L-system parameters, the methods throw a custom exception. You may use it to get a detailed explanation of which parameter(s) failed to pass validation, and format the message as you wish.
+
+```javascript
+let {getSVGCode} = require("lindsvg");
+let yaml = require("js-yaml");
+
+try {
+    console.log(getSVGCode(lsParams, svgParams));
+} catch (error) {
+    // Log the original message
+    console.error(error);
+    if (error.name === "LSError") {
+        // Get a JSON representation of the error list and format it as YAML
+        let errorJSON = error.toJSON();
+        console.log(yaml.dump(errorJSON, {indent: 4}));
+    }
+}
+```
+
 ### Compatibility note
 
 lindsvg utilizes the ECMAScript 2018 syntax. If you want to use the module in environments that do not support ES 2018, please transpile the sources with babel or whatever for your needs.

dist/lindsvg.esm.js

@@ -1,5 +1,5 @@
 /*!
-lindsvg v1.0.0
+lindsvg v1.1.0
 https://amphiluke.github.io/l-systems/
 (c) 2020 Amphiluke
 */
@@ -25,17 +25,17 @@ function checkRule(rule, msg = messages.RULE) {
 }
 
 function checkRules(rules, letterMsg, ruleMsg) {
-    let errors = new Map();
+    let errors = Object.create(null);
     Object.entries(rules).forEach(([letter, rule]) => {
         let result = checkLetter(letter, letterMsg);
         if (result === true) {
             result = checkRule(rule, ruleMsg);
         }
         if (result !== true) {
-            errors.set(letter, result);
+            errors[letter] = result;
         }
     });
-    return errors.size ? errors : true;
+    return Object.keys(errors).length ? errors : true;
 }
 
 function checkStep(step, msg = messages.STEP) {
@@ -51,7 +51,7 @@ function checkAngle(angle, msg = messages.NUMBER) {
 }
 
 function validate(lsParams) {
-    let errors = new Map();
+    let errors = Object.create(null);
     Object.entries(lsParams).forEach(([param, value]) => {
         let result = true;
         switch (param) {
@@ -73,21 +73,42 @@ function validate(lsParams) {
                 break;
         }
         if (result !== true) {
-            errors.set(param, result);
+            errors[param] = result;
         }
     });
-    return errors.size ? errors : true;
+    return Object.keys(errors).length ? errors : true;
 }
 
-function formatErrors(errors) {
-    return [...errors].reduce((accumulator, [param, error]) => {
-        if (error instanceof Map) {
-            return `${accumulator}\n${param}:${formatErrors(error).replace(/\n/g, "\n  ")}`;
-        }
-        return `${accumulator}\n${param}: ${error}`;
-    }, "");
+class LSError extends Error {
+    /**
+     * LSError constructor
+     * @param {Object} errors - Error map “parameter->message(s)”
+     * @constructor
+     */
+    constructor(errors) {
+        let message = JSON.stringify(errors, null, 2);
+        super(message);
+        // Using JSON.parse for deep cloning
+        Object.defineProperty(this, "lsErrors", {value: JSON.parse(message)});
+    }
+
+    /**
+     * Get raw object representation of the errors
+     * @return {Object}
+     */
+    toJSON() {
+        return JSON.parse(JSON.stringify(this.lsErrors));
+    }
 }
 
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/toString
+Object.defineProperty(LSError.prototype, "name", {
+    configurable: true,
+    enumerable: false,
+    writable: true,
+    value: "LSError"
+});
+
 /** @type {Rules} */
 let ctrlRules = {
     F: "",
@@ -114,7 +135,7 @@ let defaults = {
 function generate(lsParams) {
     let validity = validate(lsParams);
     if (validity !== true) {
-        throw new Error(formatErrors(validity));
+        throw new LSError(validity);
     }
     let {axiom: code, iterations} = {...defaults, ...lsParams};
     let rules = {...ctrlRules, ...lsParams.rules};

dist/lindsvg.js

@@ -1,5 +1,5 @@
 /*!
-lindsvg v1.0.0
+lindsvg v1.1.0
 https://amphiluke.github.io/l-systems/
 (c) 2020 Amphiluke
 */
@@ -31,17 +31,17 @@ https://amphiluke.github.io/l-systems/
     }
 
     function checkRules(rules, letterMsg, ruleMsg) {
-        let errors = new Map();
+        let errors = Object.create(null);
         Object.entries(rules).forEach(([letter, rule]) => {
             let result = checkLetter(letter, letterMsg);
             if (result === true) {
                 result = checkRule(rule, ruleMsg);
             }
             if (result !== true) {
-                errors.set(letter, result);
+                errors[letter] = result;
             }
         });
-        return errors.size ? errors : true;
+        return Object.keys(errors).length ? errors : true;
     }
 
     function checkStep(step, msg = messages.STEP) {
@@ -57,7 +57,7 @@ https://amphiluke.github.io/l-systems/
     }
 
     function validate(lsParams) {
-        let errors = new Map();
+        let errors = Object.create(null);
         Object.entries(lsParams).forEach(([param, value]) => {
             let result = true;
             switch (param) {
@@ -79,21 +79,42 @@ https://amphiluke.github.io/l-systems/
                     break;
             }
             if (result !== true) {
-                errors.set(param, result);
+                errors[param] = result;
             }
         });
-        return errors.size ? errors : true;
+        return Object.keys(errors).length ? errors : true;
     }
 
-    function formatErrors(errors) {
-        return [...errors].reduce((accumulator, [param, error]) => {
-            if (error instanceof Map) {
-                return `${accumulator}\n${param}:${formatErrors(error).replace(/\n/g, "\n  ")}`;
-            }
-            return `${accumulator}\n${param}: ${error}`;
-        }, "");
+    class LSError extends Error {
+        /**
+         * LSError constructor
+         * @param {Object} errors - Error map “parameter->message(s)”
+         * @constructor
+         */
+        constructor(errors) {
+            let message = JSON.stringify(errors, null, 2);
+            super(message);
+            // Using JSON.parse for deep cloning
+            Object.defineProperty(this, "lsErrors", {value: JSON.parse(message)});
+        }
+
+        /**
+         * Get raw object representation of the errors
+         * @return {Object}
+         */
+        toJSON() {
+            return JSON.parse(JSON.stringify(this.lsErrors));
+        }
     }
 
+    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/toString
+    Object.defineProperty(LSError.prototype, "name", {
+        configurable: true,
+        enumerable: false,
+        writable: true,
+        value: "LSError"
+    });
+
     /** @type {Rules} */
     let ctrlRules = {
         F: "",
@@ -120,7 +141,7 @@ https://amphiluke.github.io/l-systems/
     function generate(lsParams) {
         let validity = validate(lsParams);
         if (validity !== true) {
-            throw new Error(formatErrors(validity));
+            throw new LSError(validity);
         }
         let {axiom: code, iterations} = {...defaults, ...lsParams};
         let rules = {...ctrlRules, ...lsParams.rules};