azu / commonjs-to-es-module-codemod

Codemod that convert CommonJS(require/exports) to ES Modules(import/export) for JavaScript/TypeScript

commonjs-to-es-module-codemod

jscodeshift codemod that convert CommonJS(require/exports) to ES Modules(import/export) for JavaScript/TypeScript

Support Patterns

Exports

• named export: module.exports.foo = foo & exports.foo = foo to export { foo }
• named export: module.exports.bar = foo & exports.bar = foo to export { foo as bar }
• default export: module.exports = foo to export default foo
• ignore multiple module.exports = x

Imports

• require("mod") to import "mod"
• const foo = require("mod") to import foo from "mod"
• const { foo } = require("mod") to import { foo } from "mod"
• const foo = require("mod").foo to import { foo } from "mod"
• const bar = require("mod").foo to import { foo as bar } from "mod"
• const o = { foo: require("foo") } to import foo from "mod"; const o = { foo }

Usage

commonjs-to-es-module-codemod is published on npm.

You can convert index.js and index.ts to ES Modules using jscodeshift and unpkg.

# Install jscodeshift
npm install --global jscodeshift
# Transform using latest version
LATEST_VERSION=$(npm view commonjs-to-es-module-codemod version)
jscodeshift -t "https://unpkg.com/commonjs-to-es-module-codemod@${LATEST_VERSION}/dist/index.js" "index.js"
# Transform TypeScript
jscodeshift -t "https://unpkg.com/commonjs-to-es-module-codemod@${LATEST_VERSION}/dist/index.js" --extensions ts "index.ts"

Convert src/*.js:

LATEST_VERSION=$(npm view commonjs-to-es-module-codemod version)
find src -name "*.js" | xargs jscodeshift -t "https://unpkg.com/commonjs-to-es-module-codemod@${LATEST_VERSION}/dist/index.js"

Related

• azu/eslint-cjs-to-esm: ESLint wrapper for migration from CJS to ESM.

Tests

yarn test

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

License

MIT © azu

It includes BuonOmo/CommonJS-to-ES6-codemod.

MIT © Ulysse Buonomo [email protected]

Related

• lebab/lebab: Turn your ES5 code into readable ES6. Lebab does the opposite of what Babel does.

commonjs-to-es-module-codemod's Issues

more import transform

https://github.com/lebab/lebab/tree/master/src/transform/commonjs

Possible to use programmatically?

Is there a way to transfrom code without the command line?
Something as the pseudo code below.

import { transform } from 'jscodeshift'
import { createRequire } from 'node:module'

const require = createRequire(import.meta.url)

const cjsToEsModule = require('commonjs-to-es-module-codemod')

const out = transform('exports.toto = true', cjsToEsModule)
out // "export const toto = true"

Wrong output code from `module.exports.b = a;`

Input:

const a = () => {
    return 42;
};
module.exports.a = a;
module.exports.b = a;

Current output:

const a = () => {
    return 42;
};
export { a };
export { b as a };

Expected output:

const a = () => {
    return 42;
};
export { a };
export { a as b };

`module.exports = { a, b, ... }` may be able to be converted to `export { a, b, ... }`

module.exports = { a, b, ... } may be able to be converted to ESM named export.

Input

module.exports = { a, b, ... }

Current output

export default { a, b, ... }

Recommended output

export { a, b, ... }

Support `exports`

Support both exports and module.exports

Error: Cannot find module 'jscodeshift'

I am trying to follow the instructions that I am getting this error.
Any suggestion? I am using node v18

Error: Cannot find module 'jscodeshift'
Require stack:
- /private/var/folders/r9/0wyqy74d7630p6sxb_cfvrgr0000gp/T/jscodeshift202317-80737-16g8is6.q5z5.js
- /Users/<USER>/.nvm/versions/node/v18.12.1/lib/node_modules/jscodeshift/src/Worker.js

Wrong output code from `const fs = require('fs').promises`

Input

const fs = require('fs').promises

Current output

import { promises } from 'fs'

Expected output

import { promises as fs } from 'fs'

Fails on shebang

Hi! thanks for this mod 💖

I just tried it on some cli files that started with:

#!/usr/bin/env node

'use strict'

const commander = require('commander')

And that is translated to:

#!/usr/bin/env node'use strict'

import commander from 'commander';

Naturally after running the script it will complain that node'use strict' is not an existing interpreter.

The added semicolons are fine, but the corrupted shebang sadly makes it that we cannot use your tool as is.

If you have an idea how to fix that would be nice, otherwise i may run some kind of post-cleanup job perhaps.

All the best :)