Expertly rolled JavaScript. API + CLI for for bundling opinionated JavaScript with Rollup.js

Usage no npm install needed!

<script type="module">
  import handroll from 'https://cdn.skypack.dev/handroll';



npm build dependencies downloads license chat

Expertly rolled JavaScript

JavaScript API and CLI for for bundling opinionated JavaScript with Rollup. Provides a similar interface to Rollup with many options and plugins automatically configured based on format and package.json.


  • Automatic external module detection
  • Automatic node module resolution with improved resolution strategy
  • Automatic transforms based on filetype with built-in support for many languages
  • Automatic destination and format detection based on package.json:
    • main generates CommonJS module
    • module generates ES module bundle
    • bin generates executable
  • Higher-level formats
    • cli bundles JS into an executable
    • web bundles JS for the browser
  • Built-in minification support
  • Built-in legacy module support
  • Built-in CommonJS support
  • Built-in statistics and details view
  • Improved error handling and logging
  • Sensible defaults


$ npm install handroll -g



  handroll <entry> [options]

  --commonjs     Enable CommonJS support
  --output,   -o Destination to write output
  --format, -f   Format to output
  --formats      Comma separated list of formats to output
  --es           ES module format
  --cjs          CommonJS module format
  --cli          Executable format
  --web          Web format
  --browser      Bundle for browser
  --name         Name to use for iife module
  --sourcemap    Enable source map support
  --minify       Enable minification

  --version      Print version information
  --help         Print this usage

JavaScript API

Handroll's JavaScript API provides an interface similar to Rollup, with the bundle step being optional (and only useful if you want to cache the intermediate bundle). In most cases you'll want to use .write or .generate directly.

handroll.bundle (options) -> Promise

Create a new Bundle and cache result of bundle.rollup.

handroll.write (options) -> Promise

Create new Bundle and immediately export in appropriate format(s).

bundle.write (options) -> Promise

Write bundle in appropriate format(s).

bundle.generate (options) -> Promise

Generate output in appropriate format(s).

bundle.rollup (options) -> Promise

Automatically infer compilers, plugins, formats and other relevant options and Rollup bundle.


All Handroll operations can be passed the similiar options.

const bundle = await handroll.bundle({
  entry: 'src/index.js',  // Path to entry module, required

  // Use `format` or `formats` to customize export format. Handroll defaults to
  // ES module format. Multiple formats may be specified using `formats`:
  // formats: ['cjs', 'es']
  format: 'es',

  // Use `output` to specify where a given format should be written. By default
  // Handroll will infer output based on your package.json:
  //   format -> default output
  //   cjs    -> pkg.main
  //   es     -> pkg.module
  //   cli    -> pkg.bin
  //   web    -> pkg.name + '.js'
  output: 'dist/lib.js',

  // Use `compilers` to customize plugins used per-filetype.
  // compilers: {
  //   coffee: {
  //     verison: 1  // use CS 1.x instead of 2.x
  //   }
  // }
  // Or specify your own:
  // compilers: {
  //   js:   buble()
  //   less: less()
  // }
  compilers: {
    coffee: coffee(),
    json:   json(),
    pug:    pug(),
    styl:   stylus(),

  // Use `legacy` to specificy non-module scripts and corresponding exports.
  // Non-module scripts installed with npm will be automatically resolved.
  // legacy: {
  //   './vendor/some.lib.js': 'someLib',
  //   prismjs: 'Prism'
  // }
  legacy: null,

  // Use `plugins` to override plugins Handroll should use. By default Handroll
  // will try to automatically infer and configure the plugins you should use.
  // plugins: [buble(), commonjs()]
  plugins: null,

  // Use `external` to configure which dependencies Rollup considers external. By
  // default Handroll will try to automatically infer external dependencies based
  // on package.json. Normal dependencies are assumed to be external while
  // devDependencies are assumed to be fully subsumbed during the build step.
  // You can use `external: false` or an explicit list to disable this behavior.
  // external: Object.keys pkg.dependencies
  external: true,

  // Use `commonjs` to enable importing and customize CommonJS adaptor behavior.
  // commonjs:
  //   namedExports:
  //     './module.js': ['foo', 'bar']
  commonjs: false,

  basedir:    './',   // Customize basedir used for resolution
  details:    false,  // Print extra details about bundle
  es3:        false,  // Emit slightly more ES3-compliant output
  executable: false,  // Include shebang and chmod+x output
  minify:     false,  // Use uglify to minify bundle
  quiet:      false,  // Suppress default output
  sourcemap:  true ,  // Collect and save source maps
  strip:      false,  // Remove debugging and console log statements


import handroll from 'handroll'

// Create new bundle
const bundle = await handroll.bundle({
  entry: 'src/index.js'

// Write ES module (for use by bundlers)
await bundle.write({
  format: 'es'
  // output: pkg.module

// Write CommonJS module (for use by Node.js)
await bundle.write({
  format: 'cjs'
  // output: pkg.main

// Write ES module and CommonJS module
await bundle.write({formats: ['cjs', 'es']})

// If you specify 'main' and 'module' in your package.json, both ES module and
// CommonJS formatted bundles will be generated
await bundle.write()

// Write self-executing bundle for web using browser-friendly modules, ensuring no
// dependencies are excluded
await bundle.write({
  format: 'web',
  // external: false,
  // browser:  true,
  // output:     pkg.name + '.js',

// Write executable with shebang using new entry module
await handroll.write({
  entry:  'src/cli.js',
  format: 'cli',
  // executable: true,
  // external:   true,
  // output:     pkg.bin,

// Share options across multiple destinations
const bundle = new handroll.Bundle({
  entry:    'src/index.js',
  external: false
await Promise.all([
  bundle.write({format: 'es'}),
  bundle.write({format: 'cjs'}),

Example package.json

  "name":        "mylib",
  "main":        "lib/mylib.js",  // CommonJS output
  "module":      "lib/mylib.mjs", // ES module output
  "jsnext:main": "lib/mylib.mjs", // For compatibility with outdated bundlers

  // To ensure your generated files are packaged correctly:
  "files": [
  "scripts": {
    "prepublishOnly": "handroll src/index.js --formats cjs,es"