Webpacker-React CircleCI

Note: This is the documentation for the Git master branch. Documentation for the latest release (0.3.2) is available here.

Webpacker-React makes it easy to use React with Webpacker in your Rails applications.

It supports Webpacker 1.2+.

An example application is available: https://github.com/renchap/webpacker-react-example/


Your Rails application needs to use Webpacker and have the React integration done. Please refer to their documentation documentation for this: https://github.com/rails/webpacker/blob/master/README.md#ready-for-react

First, you need to add the webpacker-react gem to your Rails app Gemfile:

gem 'webpacker-react', "~> 0.3.2"

Once done, run bundle to install the gem.

Then you need to update your package.json file to include the webpacker-react NPM module:

./bin/yarn add webpacker-react

You are now all set!

Note about versions

Webpacker-React contains two parts: a Javascript module and a Ruby gem. Both of those components respect semantic versioning. When upgrading the gem, you need to upgrade the NPM module to the same minor version. New patch versions can be released for each of the two independently, so it is ok to have the NPM module at version A.X.Y and the gem at version A.X.Z, but you should never have a different A or X.


The first step is to register your root components (those you want to load from your HTML). In your pack file (app/javascript/packs/*.js), import your components as well as webpacker-react and register them. Considering you have a component in app/javascript/components/hello.js:

import Hello from 'components/hello'
import WebpackerReact from 'webpacker-react'

WebpackerReact.setup({Hello}) // ES6 shorthand for {Hello: Hello}

You have to make sure Turbolinks is loaded before calling WebpackerReact.initialize().

For example:

import Hello from 'components/hello'
import WebpackerReact from 'webpacker-react'
import Turbolinks from 'turbolinks'



You may also load turbolinks in regular asset pipeline application.js:

//= require "turbolinks"

In that case, make sure your packs are loaded after application.js

Now you can render React components from your views or your controllers.

Rendering from a view

Use the react_component helper. The first argument is your component's name, the second one is the props:

<%= react_component('Hello', name: 'React') %>

You can pass a tag argument to render the React component in another tag than the default div. All other arguments will be passed to content_tag:

<%= react_component('Hello', { name: 'React' }, tag: :span, class: 'my-custom-component') %>
# This will render <span class="my-custom-component" data-react-class="Hello" data-react-props="..."></span>

Rendering from a controller

class PageController < ApplicationController
  def main
    render react_component: 'Hello', props: { name: 'React' }

You can use the tag_options argument to change the generated HTML, similar to the react_component method above:

render react_component: 'Hello', props: { name: 'React' }, tag_options: { tag: :span, class: 'my-custom-component' }

You can also pass any of the usual arguments to render in this call: layout, status, content_type, etc.

Note: you need to have Webpack process your code before it is available to the browser, either by manually running ./bin/webpack or having the ./bin/webpack-watcher process running.

Hot Module Replacement

HMR allows to reload / add / remove modules live in the browser without reloading the page. This allows any change you make to your React components to be applied as soon as you save, preserving their current state.

First, install react-hot-loader (version 3):

./bin/yarn add react-hot-loader@beta

You then need to update your Webpack config.

We provide a convenience function to add the necessary changes to your config if it's not significantly different than the standard Webpacker config:


const sharedConfig = require('./shared.js')
const configureHotModuleReplacement = require('webpacker-react/configure-hot-module-replacement')

module.exports = merge(configureHotModuleReplacement(sharedConfig), ...)

If you need to change your configuration manually:

  1. add react-hot-loader/babel to your babel-loader rules:

    module: {
      rules: [
          test: /\.jsx?(.erb)?$/,
          exclude: /node_modules/,
          loader: 'babel-loader',
          options: {
            plugins: ['react-hot-loader/babel']
  2. prepend react-hot-loader/patch to your entries:

        { application: [ 'react-hot-loader/patch', '../app/javascript/packs/application.js' ],
  3. you now need to use webpack-dev-server (in place of webpack or webpack-watcher). Make sure the following line is in your development.rb:

    config.x.webpacker[:dev_server_host] = 'http://localhost:8080/'

    and start webpack-dev-server in hot replacement mode:

    ./bin/webpack-dev-server --hot
  4. finally opt in to HMR from your pack files:

    import SomeRootReactComponent from 'components/some-root-react-component'
    import WebpackerReact from 'webpacker-react/hmr'
    if (module.hot)
      module.hot.accept('components/some-root-react-component', () =>
        WebpackerReact.renderOnHMR(SomeRootReactComponent) )

You also need to ensure that output.publicPath are correctly set. This should be already handled by Webpacker.


To work on this gem locally, you first need to clone and setup the example application.

Then you need to change the example app Gemfile to point to your local repository and run bundle afterwise:

gem 'webpacker-react', path: '~/code/webpacker-react/'

Finally, you need to tell Yarn to use your local copy of the NPM module in this application, using yarn link:

$ cd ~/code/webpacker-react/javascript/webpacker_react-npm-module/
$ yarn
$ cd dist/
$ yarn             # compiles the code from src/ to dist/
$ yarn link
success Registered "webpacker-react".
info You can now run `yarn link "webpacker-react"` in the projects where you want to use this module and it will be used instead.
$ cd ~/code/webpacker-react-example/
$ yarn link webpacker-react
success Registered "webpacker-react".

After launching ./bin/webpack-watcher and ./bin/rails server in your example app directory, you can now change the Ruby or Javascript code in your local webpacker-react repository, and test it immediately using the example app.


If you changed the local javascript package, first ensure it is build (see above).

To run the test suite:

$ rake test

If you change the javascript code, please ensure there are no style errors before committing:

$ cd javascript/webpacker_react-npm-module/
$ yarn lint


Bug reports and pull requests are welcome on GitHub at https://github.com/renchap/webpacker-react. Please feel free to open issues about your needs and features you would like to be added.


  • [ ] server-side rendering (#3)


This gem has been inspired by the awesome work on react-rails and react_on_rails. Many thanks to their authors!