rollup-plugin-externals

0.0.1 verified Mon Apr 27 auth: no javascript

A Rollup plugin that mimics webpack's externals configuration, allowing you to mark dependencies as external and provide global variable names for bundling with script tags. Currently at v0.0.1, it is a lightweight alternative to @rollup/plugin-node-resolve combined with manual external handling. It maps module IDs to global variable names, emitting `module.exports = window.VariableName` stubs at build time. Suitable for library authors bundling for browser environments. No dependencies and ships TypeScript types.

Common errors

error TypeError: (0 , rp.default) is not a function ↓

cause CommonJS require used without destructuring, getting the module object instead of the externals function.

fix

Use const { externals } = require('rollup-plugin-externals') instead of const externals = require('rollup-plugin-externals').

error RollupError: Could not resolve './some-internal-module' from 'node_modules/rollup-plugin-externals/index.js' ↓

cause The plugin's internal import resolution fails when used as a transitive dependency or with hoisted node_modules.

fix

Ensure rollup-plugin-externals is installed as a direct devDependency, and delete node_modules/.cache if needed.

error Uncaught ReferenceError: module is not defined ↓

cause Using the plugin with output.format: 'es' or 'iife' but the plugin generates CJS-style stubs.

fix

Set Rollup's output.format to 'cjs' or 'iife' and ensure the target environment supports module.

Warnings

gotcha The plugin emits `module.exports = window.VariableName` for CJS output; may cause issues with Rollup's `output.format: 'es'` if not configured correctly. ↓

fix Use `output.format: 'iife'` or ensure your output format supports global variable assignments.

gotcha Only works with Rollup; not compatible with other bundlers like webpack or esbuild. ↓

fix For webpack, use built-in `externals` config; for esbuild, use `external` option with `globalName`.

deprecated Plugin is at v0.0.1; API may change in future versions without major version bump. ↓

fix Pin to exact version and test upgrades thoroughly.

Install

npm install rollup-plugin-externals

yarn add rollup-plugin-externals

pnpm add rollup-plugin-externals

Imports

externals

wrong

import externals from 'rollup-plugin-externals'

correct

import { externals } from 'rollup-plugin-externals'

This package only exports a named function; there is no default export.

externals (require)

wrong

const externals = require('rollup-plugin-externals')

correct

const { externals } = require('rollup-plugin-externals')

CommonJS require must destructure; using it as a default will not work.

TypeScript type
```
import type { ExternalsOptions } from 'rollup-plugin-externals'
```
TypeScript users can import the type for options object.

Quickstart

Demonstrates how to use the externals plugin in a Rollup config to map 'react' and 'react-dom' to global variables for IIFE output.

import { defineConfig } from 'rollup';
import { externals } from 'rollup-plugin-externals';

export default defineConfig({
  input: 'src/index.js',
  output: {
    dir: 'dist',
    format: 'iife',
  },
  plugins: [
    externals({
      'react': 'React',
      'react-dom': 'ReactDOM',
    }),
  ],
});