cheatsheets/rollup.md

title	category	layout	updated	keywords	intro
Rollup.js	JavaScript libraries	2017/sheet	2017-11-01	rollup.watch bundle rollup.config.js	[Rollup](https://rollupjs.org/) Rollup is a module bundler for JavaScript which compiles small pieces of code into something larger and more complex, such as a library or application.

Basic config

rollup.config.js

export default {
  input: 'src/main.js',
  output: {
    file: 'bundle.js',
    format: 'cjs'
  }
}

Terminal

npm install -D rollup

| rollup -c -o bundle.js | bundle using config | rollup main.js --o bundle.js --f cjs | bundle | rollup --watch | bundle continuously

You may need to use ./node_modules/.bin/rollup as a command if you did not install rollup globally

Mutiple files

rollup.config.js

export default [
  {
    input: 'src/main.js',
    output: {
      file: __dirname + '/public/main.js',
      format: 'cjs',
      name: 'main'
    }
  },
  {
    input: 'src/vendor.js',
    output: {
      file: __dirname + 'public/vendor.js',
      format: 'cjs',
      name: 'vendor'
    }
  }
]

This creates main.js and vendor.js.

Using plugins

Plugins

Terminal

npm install -D rollup-plugin-json

rollup.config.js

import json from 'rollup-plugin-json';

export default {
  input: 'src/main.js',
  output: {
    file: 'bundle.js',
    format: 'cjs'
  },
  plugins [ json() ]
}

npm packages

Terminal

npm install --save-dev rollup-plugin-node-resolve

rollup.config.js

import resolve from 'rollup-plugin-node-resolve';

export default {
  input: 'src/main.js',
  ouptut: {
    file: 'bundle.js',
    format: 'cjs'
  },
  plugins: [ resolve() ]
}

This time when you run a npm run build, no warning is emitted and contains the imported modules

Peer dependencies

Terminal

npm install -D rollup-plugin-node-resolve

rollup.config.js

import resolve from 'rollup-plugin-node-resolve';

export default {
  input: 'src/main.js',
  output: {
    file: 'bundle.js',
    format: 'cjs'
  },
  plugins: [resolve({
    // pass custom options to the resolve plugin
    customResolveOptions: {
      moduleDirectory: 'node_modules'
    }
  })],
  // indicate which modules should be treated as external
  external: ['lodash']
}

Babel

Terminal

npm install -D rollup-plugin-babel

rollup.config.js

import resolve from 'rollup-plugin-node-resolve';
import babel from 'rollup-plugin-babel';

export default {
  input: 'src/main.js',
  output: {
    file: 'bundle.js',
    format: 'cjs'
  },
  plugins: [
    resolve(),
    babel({
      exclude: 'node_modules/**' // only transpile our source code
    })
  ]
}

src/.babelrc

{
  "presets": [
    ["latest", {
      "es2015": {
        "modules": false
      }
    }]
  ],
  "plugins": ["external-helpers"]
}