rollup-plugin-commonjs

Convert CommonJS modules to ES6, so they can be included in a Rollup bundle

Installation

npm install --save-dev rollup-plugin-commonjs

Usage

Typically, you would use this plugin alongside rollup-plugin-node-resolve, so that you could bundle your CommonJS dependencies in node_modules.

import { rollup } from 'rollup';
import commonjs from 'rollup-plugin-commonjs';
import nodeResolve from 'rollup-plugin-node-resolve';

rollup({
  entry: 'main.js',
  plugins: [
    nodeResolve({
      jsnext: true,
      main: true
    }),

    commonjs({
      // non-CommonJS modules will be ignored, but you can also
      // specifically include/exclude files
      include: 'node_modules/**',  // Default: undefined
      exclude: [ 'node_modules/foo/**', 'node_modules/bar/**' ],  // Default: undefined

      // search for files other than .js files (must already
      // be transpiled by a previous plugin!)
      extensions: [ '.js', '.coffee' ],  // Default: [ '.js' ]

      // if true then uses of `global` won't be dealt with by this plugin
      ignoreGlobal: false,  // Default: false

      // if false then skip sourceMap generation for CommonJS modules
      sourceMap: false,  // Default: true
      
      // explicitly specify unresolvable named exports
      // (see below for more details)
      namedExports: { './module.js': ['foo', 'bar' ] }  // Default: undefined 
    })
  ]
}).then(...)

Custom named exports

This plugin will attempt to create named exports, where appropriate, so you can do this...

// importer.js
import { named } from './exporter.js';

// exporter.js
module.exports = { named: 42 }; // or `exports.named = 42;`

...but that's not always possible:

// importer.js
import { named } from 'my-lib';

// my-lib.js
var myLib = exports;
myLib.named = 'you can\'t see me';

In those cases, you can specify custom named exports:

commonjs({
  namedExports: {
    // left-hand side can be an absolute path, a path
    // relative to the current directory, or the name
    // of a module in node_modules
    'node_modules/my-lib/index.js': [ 'named' ]
  }
});

License

MIT