Last active
March 31, 2026 18:51
-
-
Save DaggieBlanqx/0c7c8340d32f60d65fa1ec42ba1ddb78 to your computer and use it in GitHub Desktop.
For converting ESM to CJS
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| const fs = require('fs') | |
| const path = require('path') | |
| const files = process.argv.slice(2) | |
| function convertFile (filePath) { | |
| let src = fs.readFileSync(filePath, 'utf8') | |
| const original = src | |
| // 1. import X from 'y' → const X = require('y') | |
| src = src.replace(/^import\s+(\w+)\s+from\s+(['"`][^'"`]+['"`]);?/gm, 'const $1 = require($2);') | |
| // 2. import { a, b, c } from 'y' → const { a, b, c } = require('y') | |
| src = src.replace(/^import\s+(\{[^}]+\})\s+from\s+(['"`][^'"`]+['"`]);?/gm, 'const $1 = require($2);') | |
| // 3. import * as X from 'y' → const X = require('y') | |
| src = src.replace(/^import\s+\*\s+as\s+(\w+)\s+from\s+(['"`][^'"`]+['"`]);?/gm, 'const $1 = require($2);') | |
| // 4. export default X → module.exports = X | |
| src = src.replace(/^export\s+default\s+/gm, 'module.exports = ') | |
| // 5. export const X = ... → const X = ... then append module.exports.X = X | |
| const namedExports = [] | |
| src = src.replace(/^export\s+const\s+(\w+)\s*=/gm, (match, name) => { | |
| namedExports.push(name) | |
| return `const ${name} =` | |
| }) | |
| // 6. export { a, b, c } → module.exports = { a, b, c } | |
| src = src.replace(/^export\s+\{([^}]+)\};?/gm, (match, names) => { | |
| return `module.exports = {${names}};` | |
| }) | |
| // 7. export function X → function X then append module.exports.X = X | |
| src = src.replace(/^export\s+function\s+(\w+)/gm, (match, name) => { | |
| namedExports.push(name) | |
| return `function ${name}` | |
| }) | |
| // Append named export assignments at the end | |
| if (namedExports.length > 0) { | |
| const unique = [...new Set(namedExports)] | |
| src = src.trimEnd() + '\n\n' + unique.map(n => `module.exports.${n} = ${n};`).join('\n') + '\n' | |
| } | |
| if (src !== original) { | |
| fs.writeFileSync(filePath, src, 'utf8') | |
| console.log('✅ Converted:', filePath) | |
| } else { | |
| console.log('⚠️ No changes:', filePath) | |
| } | |
| } | |
| files.forEach(f => { | |
| try { | |
| convertFile(f) | |
| } catch (err) { | |
| console.error('❌ Error on', f, err.message) | |
| } | |
| }) | |
| // Usage: | |
| // node convert-esm-to-cjs.js <file1> [file2] [file3] ... | |
| // | |
| // Examples: | |
| // node convert-esm-to-cjs.js src/utils.js | |
| // node convert-esm-to-cjs.js src/utils.js src/helpers.js lib/index.js | |
| // node convert-esm-to-cjs.js src/**/*.js | |
| // | |
| // Before (ESM): | |
| // import path from 'path' | |
| // import { readFile } from 'fs' | |
| // import * as _ from 'lodash' | |
| // | |
| // export default function main() { return 42 } | |
| // | |
| // export function greet(name) { return `Hello, ${name}` } | |
| // export const PI = 3.14 | |
| // | |
| // export { greet, PI } | |
| // | |
| // After (CJS): | |
| // const path = require('path'); | |
| // const { readFile } = require('fs'); | |
| // const _ = require('lodash'); | |
| // | |
| // module.exports = function main() { return 42 } | |
| // | |
| // function greet(name) { return `Hello, ${name}` } | |
| // const PI = 3.14 | |
| // | |
| // module.exports = { greet, PI }; | |
| // | |
| // module.exports.greet = greet; | |
| // module.exports.PI = PI; |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment