babel-plugin-transform-modules-requirejs-babel

0.2.0 verified Sat Apr 25 auth: no javascript

A Babel plugin for transforming ESM modules to AMD modules, designed to work with RequireJS and the requirejs-babel7 plugin. Current stable version 0.2.0 (May 2025). It replaces the combination of @babel/plugin-transform-modules-amd, babel-plugin-amd-checker, babel-plugin-amd-default-export, and babel-plugin-module-resolver-standalone, solving limitations around mixing ESM and AMD modules at any dependency level and handling default exports without wrapping. Supports customising module path resolution via a resolvePath function. Infrequent releases; maintained by a single author.

Common errors

error Error: Module 'babel-plugin-transform-modules-requirejs-babel' not found ↓

cause The plugin is not installed or is missing from node_modules.

fix

Run npm install -D babel-plugin-transform-modules-requirejs-babel to install it as a dev dependency.

error TypeError: resolvePath is not a function ↓

cause The resolvePath option was provided as a string instead of a function.

fix

Provide a function: resolvePath(sourcePath, currentFile) { ... } not a string like 'es6!source'.

error SyntaxError: Unexpected token 'export' ↓

cause Babel is not configured to transpile ES modules; the plugin may not be applied.

fix

Ensure the plugin is listed in your Babel config under 'plugins' (not 'presets') and that Babel is running on the file. Example: plugins: ['transform-modules-requirejs-babel'].

error ReferenceError: define is not defined ↓

cause The AMD module output expects RequireJS to be loaded in the browser, but RequireJS is not present.

fix

Include RequireJS script before your compiled modules. Example: <script src='require.js' data-main='main'></script>.

Warnings

gotcha The plugin assumes that AMD modules without dependencies (empty define) are not mixed with ESM; if you have AMD modules with no deps, they may be transformed incorrectly. ↓

fix Upgrade to >=0.0.4 which fixes recognition of AMD modules without dependencies.

gotcha ResolvePath function must handle the three pseudo-modules 'require', 'module', 'exports' explicitly to avoid prefixing them. ↓

fix Always check sourcePath against 'require', 'module', 'exports' in resolvePath, as shown in the example.

deprecated This plugin replaces a combination of four other plugins; if you are using those, migrate to this single plugin to avoid conflicts and missing features. ↓

fix Remove '@babel/plugin-transform-modules-amd', 'babel-plugin-amd-checker', 'babel-plugin-amd-default-export', 'babel-plugin-module-resolver-standalone' and use this plugin instead.

breaking The plugin now transforms default exports without wrapping in { default: ... } to keep compatibility with RequireJS. This may break code expecting the default property wrapper. ↓

fix Update consuming AMD modules to treat direct exports as the default value; if you need the wrapper, set the addDefaultProperty option (not yet implemented) or use babel-plugin-amd-default-export with addDefaultProperty: true before this plugin.

Install

npm install babel-plugin-transform-modules-requirejs-babel

yarn add babel-plugin-transform-modules-requirejs-babel

pnpm add babel-plugin-transform-modules-requirejs-babel

Imports

default

wrong

import transformModulesRequirejsBabel from 'babel-plugin-transform-modules-requirejs-babel'

correct

module.exports = { plugins: ['transform-modules-requirejs-babel'] }

The plugin is used as a string in Babel config, not imported directly. Use the plugin name in .babelrc or babel.config.js.

resolvePath

wrong

plugins: [['babel-plugin-transform-modules-requirejs-babel', { resolvePath: 'es6!' }]]

correct

['transform-modules-requirejs-babel', { resolvePath: (source, currentFile) => 'es6!' + source }]

resolvePath must be a function, not a string. It receives sourcePath and currentFile arguments.

Plugin as CommonJS require

wrong

const plugin = require('babel-plugin-transform-modules-requirejs-babel').default

correct

const plugin = require('babel-plugin-transform-modules-requirejs-babel'); module.exports = { plugins: [plugin] }

This plugin is CJS-compatible. Using .default would be incorrect as it's not an ESM default export.

Quickstart

Shows basic Babel configuration with the plugin, optional resolvePath customization, and expected AMD output from an ESM module.

// Install: npm i -D babel-plugin-transform-modules-requirejs-babel
// .babelrc or babel.config.js
module.exports = {
  presets: [],
  plugins: [
    // Basic usage: no options
    'transform-modules-requirejs-babel'
  ]
};

// Optionally with custom resolvePath:
// plugins: [
//   [
//     'transform-modules-requirejs-babel',
//     {
//       resolvePath(sourcePath, currentFile) {
//         if (sourcePath.indexOf('!') < 0 && sourcePath !== 'require' &&
//             sourcePath !== 'module' && sourcePath !== 'exports') {
//           return 'es6!' + sourcePath;
//         }
//       }
//     }
//   ]
// ]

// Example ESM input 'src/main.js':
// import { helper } from './helper';
// export default function main() { helper(); }

// After Babel transformation (AMD output):
// define('src/main', ['./helper'], function (_helper) {
//   'use strict';
//   function main() { (0, _helper.helper)(); }
//   return main;
// });