Ruby gem for automatically transforming JSX and using React in Rails.
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react-rails is a ruby gem which makes it easier to use React and JSX in your Ruby on Rails application.

This is done in 2 ways:

  1. making it easy to include react.js as part of your dependencies in application.js.
  2. transforming JSX into regular JS on request, or as part of asset precompilation.


We're specifically targeting versions of Ruby on Rails which make use of the asset pipeline, which means Rails 3.1+.

As with all gem dependencies, we strongly recommend adding react-rails to your Gemfile and using bundler to manage your application's dependencies.

# Gemfile

gem 'react-rails', '~> 1.0.0'



In order to use React client-side in your application, you must make sure the browser requests it. One way to do that is to drop react.js into vendor/assets/javascript/ and by default your application manifest will pick it up. There are downsides to this approach, so we made it even easier. Once you have react-rails installed, you can just add a line into your config file (see Configuring) and require react directly in your manifest:

You can require it in your manifest:

// app/assets/application.js

//= require react

Alternatively, you can include it directly as a separate script tag:

# app/views/layouts/application.erb.html

<%= javascript_include_tag "react" %>


To transform your JSX into JS, simply create .js.jsx files, and ensure that the file has the /** @jsx React.DOM */ docblock. These files will be transformed on request, or precompiled as part of the assets:precompile task.

Unobtrusive javascript

react_ujs will call React.renderComponent for every element with data-react-class attribute. React properties can be specified by data-react-props attribute in JSON format. For example:

<!-- react_ujs will execute `React.renderComponent(HelloMessage({name:"Bob"}), element)` -->
<div data-react-class="HelloMessage" data-react-props="<%= {:name => 'Bob'}.to_json %>" />

react_ujs will also scan DOM elements and call React.unmountComponentAtNode on page unload. If you want to disable this behavior, remove data-react-class attribute in componentDidMount.

To use react_ujs, simply require it after react (and after turbolinks if Turbolinks is used):

// app/assets/application.js

//= require turbolinks
//= require react
//= require react_ujs

Viewer helper

There is a viewer helper method react_component. It is designed to work with react_ujs and takes React class name, properties, HTML options as arguments:

react_component('HelloMessage', :name => 'John')
# <div data-react-class="HelloMessage" data-react-props="{&quot;name&quot;:&quot;John&quot;}"></div>

By default, a <div> element is used. Other tag and HTML attributes can be specified:

react_component('HelloMessage', {:name => 'John'}, :span)
# <span data-...></span>

react_component('HelloMessage', {:name => 'John'}, {:id => 'hello', :class => 'foo', :tag => :span})
# <span class="foo" id="hello" data-...></span>



There are 2 variants available. :development gives you the unminified version of React. This provides extra debugging and error prevention. :production gives you the minified version of React which strips out comments and helpful warnings, and minifies.

# config/environments/development.rb
MyApp::Application.configure do
  config.react.variant = :development

# config/environments/production.rb
MyApp::Application.configure do
  config.react.variant = :production


Beginning with React v0.5, there is another type of build. This build ships with some "add-ons" that might be useful - take a look at the React documentation for details. In order to make these available, we've added another configuration (which defaults to false).

MyApp::Application.configure do
  config.react.addons = true


It is possible to use JSX with CoffeeScript. The caveat is that you will still need to include the docblock. Since CoffeeScript doesn't allow /* */ style comments, we need to do something a little different. We also need to embed JSX inside backticks so CoffeeScript ignores the syntax it doesn't understand. Here's an example:

###* @jsx React.DOM ###

Component = React.createClass
  render: ->
    `<ExampleComponent videos={this.props.videos} />`

Changing react.js and JSXTransformer.js versions

In some cases you may want to have your react.js and JSXTransformer.js files come from a different release than the one, that is specified in the react-rails.gemspec. To achieve that, you have to manually replace them in your app.


Just put another version of react.js or JSXTransformer.js under /vendor/assets/react directory. If you need different versions of react.js for production and development, then use a subdirectory named after config.react.variant, e.g. you set config.react.variant = :development so for this environment react.js is expected to be in /vendor/assets/react/development

Things to remember

If you replace JSXTransformer.js in production environment, you have to restart your rails instance, because the jsx compiler context is cached.

Name of the JSXTransformer.js file is case-sensitive.