Build CommonJS version of gavel

package.json

@@ -3,6 +3,8 @@
   "version": "0.0.0-semantically-released",
   "description": "Validator of HTTP transactions (JavaScript implementation)",
   "main": "build/index.js",
+  "unpkg": "build/index.umd.js",
+  "jsdelivr": "build/index.umd.js",
   "typings": "typings.d.ts",
   "engines": {
     "node": ">= 10.18"

rollup.config.js

@@ -5,10 +5,12 @@ const { terser } = require('rollup-plugin-terser');
 
 const packageJson = require('./package.json');
 
+const dependencies = Object.keys(packageJson.dependencies);
+
 const buildUmd = {
   input: 'lib/index.js',
   output: {
-    file: packageJson.main,
+    file: packageJson.unpkg,
     format: 'umd',
     name: 'gavel',
     exports: 'named',
@@ -28,4 +30,41 @@ const buildUmd = {
   ]
 };
 
-module.exports = [buildUmd];
+const buildCjs = {
+  input: 'lib/index.js',
+  output: {
+    file: packageJson.main,
+    format: 'cjs',
+    exports: 'named'
+  },
+  external: (id) => {
+    if (dependencies.includes(id)) {
+      return true;
+    }
+
+    // url is a built-in module and should not be bundled either
+    if (id === 'url') {
+      return true;
+    }
+
+    // There are some deep imports of ajv files
+    if (id.startsWith('ajv/')) {
+      return true;
+    }
+
+    return false;
+  },
+  plugins: [
+    resolve({
+      browser: false,
+
+      // Forbid bundling of NodeJS built-ins (i.e. "fs", "path").
+      // Throw when such modules are present in the bundle.
+      preferBuiltins: false
+    }),
+    json(),
+    commonjs()
+  ]
+};
+
+module.exports = [buildUmd, buildCjs];