12/30/2015 - 7:37 PM

Rails + Browserify + React + es7

Rails + Browserify + React + es7

1. Gemfile

gem 'browserify-rails', '1.5.0' # until fix:
gem 'react-rails'

Browserify-rails allows to use browserify within assets pipeline. React-rails is here only to allow to use #react_component (and thus, prerendering).

Note that jquery-rails can be removed from Gemfile, the npm version of jquery and jquery-ujs will be used instead.

2. package.json

Here is a typical package json for es7 + react + rails:

Versions may need update. npm-check is killing it for that.

  "name": "my app",
  "dependencies": {
    "babel-plugin-syntax-async-functions": "^6.3.13",
    "babel-plugin-transform-regenerator": "^6.3.18",
    "babel-polyfill": "^6.3.14",
    "babel-preset-es2015": "^6.3.13",
    "babel-preset-react": "^6.3.13",
    "babel-preset-stage-0": "^6.3.13",
    "babelify": "^7.2.0",
    "browserify": "^12.0.1",
    "browserify-incremental": "^3.0.1",
    "es6-promise": "^3.0.2",
    "fetch": "^0.3.6",
    "jquery": "^2.1.4",
    "jquery-ujs": "^1.0.4",
    "react": "^0.14.3",
  "license": "MIT",
  "engines": {
    "node": ">= 0.10"
  "devDependencies": {
    "babelify": "^7.2.0"

The fetch plugin is a polyfill that allows to use fetch in any browser.

To add a js plugin in your application, simply add a line in the dependencies object and run npm-check -u (or npm install if you don't like sexyness).

3. config/application.rb

Add at the end of Application class:

config.browserify_rails.commandline_options = "-t [ babelify --presets [ es2015 react stage-0 ] --plugins [ syntax-async-functions transform-regenerator ] ]"
  • es2015 and stage-0 babel presets allow to parse cutting edge es7
  • react babel preset allows to parse jsx
  • syntax-async-function and transform-regenerator allow to use es7 async functions

4. app/assets/javascripts/application.js

//= require_self
//= require react-server
//= require react_ujs

window.$ = window.jQuery = global.$ = require('jquery');
var React = window.React = global.React = require('react');
require( 'jquery-ujs' );
require( 'fetch' );
require( './components' );

Sprockets is only used to require current script and helpers from react-rails. All other files will be imported using browserify.

5. app/assets/javascripts/components.js

require( 'babel-polyfill' );

global.MyFirstComponent = require( 'components/my_first_component' ).default;
global.MySecondComponent = require( 'components/my_second_component' ).default;

This is the central requiring script, that will load all files in the pipeline. Think of it as this root file in ruby gems that just require all the other files (although, I prefer to only require root components, and let them require further subcomponents they need).

A few remarks:

  • this is in components.js rather than application.js, because this is the file server side prerendering will load. Anything declared in application.js won't be available to prerendering
  • requiring babel-polyfill is mandatory to use es7 async functions
  • for a reason I don't understand, it is not possible to use the es7 import syntax in that root file, so you have to use require(...).default instead

6. write some es7 code \o/

Here is an example:

// app/assets/javascripts/components/hello_world.js

import Title      from 'components/title';
import LoremIpsum from 'components/lorem_ipsum';

var propTypes = {
  name: React.PropTypes.string.isRequired,

export default class HelloWorld extends React.Component {
  constructor( props ){
    super( props );
    this.state = { name: };

  changeName = async () => {
    let resp = await fetch( '/get_new_name' );
    resp = await resp.json();
    this.setState({ name: });

    return (
      <div onClick={this.changeName}>
        <Title>Hello {}!</Title>
        <LoremIpsum />

HelloWorld.propTypes = propTypes;

Do not forget to require this file in your component.js:

global.HelloWorld = require( 'components/hello_world' ).default;

7. load the component in view

From here, it's just stuff as usual:

      = react_component 'HelloWorld', { name: }, prerender: true