Add transformation to CJS

Author: lahmatiy

.github/workflows/build.yml

@@ -16,9 +16,6 @@ jobs:
                   cache: "npm"
             - run: npm ci
             - run: npm run lint
-            - run: npm run bundle-and-test
-              env:
-                  REPORTER: "min"
             - run: npm run coverage
               env:
                   REPORTER: "min"

.gitignore

@@ -1 +1,3 @@
 node_modules
+cjs
+cjs-test

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 - Allowed args after and between options
 - Replaced `chalk` with `ansi-colors`
-- Migrated to ESM
+- Migrated to ESM (CommonJS is still supported)
 
 ## 3.0.0-beta.1
 

package-lock.json

@@ -23,6 +23,7 @@
     "./package.json": "./package.json"
   },
   "files": [
+    "cjs",
     "lib"
   ],
   "engines": {
@@ -35,12 +36,19 @@
     "c8": "^7.10.0",
     "eslint": "^8.4.1",
     "mocha": "^9.1.3",
+    "rollup": "^2.61.1",
     "test-console": "^1.1.0"
   },
   "scripts": {
     "lint": "eslint lib test",
     "lint-and-test": "npm run lint && npm test",
     "test": "mocha --reporter ${REPORTER:-progress}",
-    "coverage": "c8 --reporter=lcovonly npm test"
+    "test:cjs": "mocha cjs-test --reporter ${REPORTER:-progress}",
+    "build": "npm run esm-to-cjs",
+    "build-and-test": "npm run esm-to-cjs-and-test",
+    "esm-to-cjs": "node scripts/esm-to-cjs",
+    "esm-to-cjs-and-test": "npm run esm-to-cjs && npm run test:cjs",
+    "coverage": "c8 --reporter=lcovonly npm test",
+    "prepublishOnly": "npm run lint-and-test && npm run build-and-test"
   }
 }

package.json

@@ -0,0 +1,76 @@
+import fs from 'fs';
+import path from 'path';
+import { rollup } from 'rollup';
+
+const external = [
+    'fs',
+    'path',
+    'assert',
+    'test-console',
+    'ansi-colors',
+    'clap'
+];
+
+function removeCreateRequire(id) {
+    return fs.readFileSync(id, 'utf8')
+        .replace(/import .+ from 'module';/, '')
+        .replace(/const require = .+;/, '');
+}
+
+function replaceContent(map) {
+    return {
+        name: 'file-content-replacement',
+        load(id) {
+            const key = path.relative('', id);
+
+            if (map.hasOwnProperty(key)) {
+                return map[key](id);
+            }
+        }
+    };
+}
+
+function readDir(dir) {
+    return fs.readdirSync(dir)
+        .filter(fn => fn.endsWith('.js'))
+        .map(fn => `${dir}/${fn}`);
+}
+
+async function build(outputDir, ...entryPoints) {
+    const startTime = Date.now();
+
+    console.log();
+    console.log(`Convert ESM to CommonJS (output: ${outputDir})`);
+
+    const res = await rollup({
+        external,
+        input: entryPoints,
+        plugins: [
+            replaceContent({
+                'lib/version.js': removeCreateRequire
+            })
+        ]
+    });
+    await res.write({
+        dir: outputDir,
+        entryFileNames: '[name].cjs',
+        format: 'cjs',
+        exports: 'auto',
+        preserveModules: true,
+        interop: false,
+        esModule: false,
+        generatedCode: {
+            constBindings: true
+        }
+    });
+    await res.close();
+
+    console.log(`Done in ${Date.now() - startTime}ms`);
+}
+
+async function buildAll() {
+    await build('./cjs', 'lib/index.js');
+    await build('./cjs-test', ...readDir('test'));
+}
+
+buildAll();

scripts/esm-to-cjs.js

@@ -1,12 +1,12 @@
-import { equal, notDeepEqual, deepEqual } from 'assert';
+import { equal, deepEqual, strictEqual } from 'assert';
 import * as clap from 'clap';
 
 describe('action()', () => {
     it('should have an expected input', () => {
         const calls = [];
         const command = clap.command('test [foo]')
             .option('--bar', 'bar option')
-            .action((...args) => {
+            .action(function(...args) {
                 calls.push({
                     this: this,
                     arguments: args
@@ -16,7 +16,7 @@ describe('action()', () => {
         command.run(['abc', '--', 'rest', 'args']);
 
         equal(calls.length, 1);
-        notDeepEqual(calls[0].this, command);
+        strictEqual(calls[0].this, null);
         deepEqual(calls[0].arguments, [{
             commandPath: ['test'],
             options: { bar: false },