Browserify transform to apply Rollup (UNMAINTAINED)
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rollupify Build Status No Maintenance Intended

Browserify transform to apply Rollup, converting ES6/ES2015 modules into one big CommonJS module.

This tends to result in smaller bundle sizes, due to Rollup's tree-shaking and scope-hoisting capabilities.

⚠️ Maintenance notice: This repo is unmaintained. I consider it largely a hack for migrating existing Browserify/CommonJS projects to Rollup/ESM. Probably you should just use Rollup instead, with plugins like rollup-plugin-commonjs and rollup-plugin-node-resolve, or manually run rollup before browserify.


npm install rollupify


browserify -t rollupify index.js > output.js

Or in your package.json:

"browserify": {
  "transform": ["rollupify"]



// index.js
import hello from './hello';
export default hello;
// hello.js
export default "hello world";


(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
'use strict';

var hello = "hello world";


module.exports = hello;

Using alongside other transforms

If you are using other transforms like babelify, make sure you apply the transforms in the right order. rollupify should apply before babelify:

browserify -t rollupify -t babelify index.js > output.js

Or when configuring:

"browserify": {
  "transform": ["rollupify", "babelify"]


rollupify only works on ES6/ES2015 modules. Any require() statements will be left untouched, and passed on to Browserify like normal.

Sourcemaps are supported, assuming you pass --debug or {debug: true} into Browserify.

Need more evidence that Rollup and ES6 modules are awesome? See rollup-comparison and A better build system with Rollup.

Need to get started converting your CommonJS codebase into ES6? Try cjs-to-es6.

Customising rollup

Given a rollup.config.js like:

module.exports = {
  plugins: [
      exclude: 'node_modules/**'

Use it through the command line:

browserify -t [ rollupify --config rollup.config.js ] index.js > output.js

Or in your package.json:

"browserify": {
  "transform": ["rollupify", {"config": "rollup.config.js"}]

If you are using Browserify in JavaScript, you can also pass in the config object directly:

var b = browserify('./')
  .transform('rollupify', {
    config: { /* your rollup config goes here */ }