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Need Help with Rails + Webpack + React? Want better performance?

Aloha, I'm Justin Gordon the creator and maintainer of React on Rails. I offer a React on Rails Pro Support Plan, and I can help you with:

• Optimizing your webpack setup for React on Rails.
• Upgrading from older React on Rails to newer versions.
• Better performance client and server side.
• Migrating from Angular to React.
• Best practices based on 4 years of React on Rails experience.
• Early access to the React on Rails Pro Gem and Node code, including:
  • ShakaCode's Node.js rendering server for better performance for server rendering (used now at egghead.io).
  • Performance helpers, especially for server rendering
  • Webpack configuration examples

Please email me for a free half-hour project consultation, on anything from React on Rails to any aspect of web development.

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React on Rails is based on Webpacker!

Given that Webpacker already provides React integration, why would you use "React on Rails"? Additional features of React on Rails include:

1. Server rendering, often for SEO optimization.
2. Easy passing of props directly from your Rails view to your React components rather than having your Rails view load and then make a separate request to your API.
3. Redux and React-Router integration
4. Localization support
5. Rspec test helpers to ensure your Webpack bundles are ready for tests
6. A supportive community

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Steps to a New App with rails/webpacker v3 plus latest React on Rails:

First be sure to run rails -v and check that you are using Rails 5.1.3 or above. If you are using an older version of Rails, you'll need to install webpacker with React per the instructions here.

Basic installation for a new Rails App

See below for steps on an existing Rails app

1. New Rails app: rails new my-app --webpack=react. cd into the directory.
2. Add gem version: gem 'react_on_rails', '11.0.0' # Use the exact gem version to match npm version
3. bundle install
4. Commit this to git (or else you cannot run the generator unless you pass the option --ignore-warnings).
5. Run the generator: rails generate react_on_rails:install
6. Start the app: rails s
7. Visit http://localhost:3000/hello_world

Turn on server rendering

1. Edit app/views/hello_world/index.html.erb and set prerender to true.
2. Refresh the page.

This is the line where you turn server rendering on by setting prerender to true:

<%= react_component("HelloWorld", props: @hello_world_props, prerender: false) %>

---

Community Resources

Please click to subscribe to keep in touch with Justin Gordon and ShakaCode. I intend to send announcements of new releases of React on Rails and of our latest blog articles and tutorials. Subscribers will also have access to exclusive content, including tips and examples.

• Slack Room: Contact us for an invite to the ShakaCode Slack room! Let us know if you want to contribute.
• forum.shakacode.com: Post your questions
• @railsonmaui on Twitter
• For a live, open source, example of this gem, see www.reactrails.com.
• See Projects using and KUDOS for React on Rails. Please submit yours! Please edit either page or email us and we'll add your info. We also love stars as it helps us attract new users and contributors.
• See NEWS.md for more notes over time.

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Testimonials

From Joel Hooks, Co-Founder, Chief Nerd at egghead.io, January 30, 2017:

For more testimonials, see Live Projects and Kudos.

---

Articles, Videos, and Podcasts

Articles

• Introducing React on Rails v9 with Webpacker Support for an overview of the integration of React on Rails with Webpacker.
• Webpacker Lite: Why Fork Webpacker?
• React on Rails, 2000+ 🌟 Stars
• The React on Rails Doctrine
• Simple Tutorial.

Videos

• Video of running the v9 installer with Webpacker v3. History, motivations, philosophy, and overview.

1. GORUCO 2017: Front-End Sadness to Happiness: The React on Rails Story by Justin Gordon
2. egghead.io: Creating a component with React on Rails
3. egghead.io: Creating a redux component with React on Rails
4. React On Rails Tutorial Series
5. History and Motivation
6. Basic Tutorial Walkthrough
7. Code Walkthrough

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React on Rails

Project Objective: To provide an opinionated and optimal framework for integrating Ruby on Rails with React via the Webpacker gem.

React on Rails integrates Facebook's React front-end framework with Rails. React v0.14.x and greater is supported, with server rendering. Redux and React-Router are supported as well, also with server rendering, using execJS.

The ability to use a standalone Node Rendering server for better performance and tooling is supported for React on Rails Pro. Contact [email protected] for more information.

Table of Contents

• Features
• Why Webpack?
• rails/webpacker or custom setup for Webpack?
• Getting Started with an existing Rails app
  • Installation Overview
  • Initializer Configuration: config/initializers/react_on_rails.rb
  • Including your React Component in your Rails Views
  • I18n
  • Convert rails-5 API only app to rails app
  • NPM
  • Webpacker Configuration
• How it Works
  • Client-Side Rendering vs. Server-Side Rendering
  • Building the Bundles
  • Rails Context and Generator Functions
  • Globally Exposing Your React Components
  • ReactOnRails View Helpers API
  • ReactOnRails JavaScript API
  • React-Router
  • Deployment
• Integration with Node.js for Server Rendering
• Additional Documentation
• Contributing
• License
• Authors
• About ShakaCode

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Features

Like the react-rails gem, React on Rails is capable of server-side rendering with fragment caching and is compatible with turbolinks. While the initial setup is slightly more involved, it allows for advanced functionality such as:

• Redux
• Webpack optimization functionality
• React Router

See the react-webpack-rails-tutorial for an example of a live implementation and code.

Why Webpack?

Webpack is used to generate JavaScript and CSS "bundles" directly to your /public directory. webpacker provides view helpers to access the Webpack generated (and fingerprinted) JS and CSS. These files totally skip the Rails asset pipeline. You are responsible for properly processing your Webpack output via the Webpack config files.

This usage of webpack fits neatly and simply into existing Rails apps. You can include React components on a Rails view with a simple helper.

Compare this to some alternative approaches for SPAs (Single Page Apps) that utilize Webpack and Rails. They will use a separate node server to distribute web pages, JavaScript assets, CSS, etc., and will still use Rails as an API server. A good example of this is our ShakaCode team member Alex's article Universal React with Rails: Part I.

Webpack Configuration: custom setup for Webpack or rails/webpacker?

Version 9 of React on Rails added support for the rails/webpacker view helpers so that Webpack produced assets would no longer pass through the Rails asset pipeline. As part of this change, React on Rails added a configuration option to support customization of the node_modules directory. This allowed React on Rails to support the rails/webpacker configuration of the Webpack configuration.

A key decision in your use React on Rails is whether you go with the rails/webpacker default setup or the traditional React on Rails setup of putting all your client side files under the /client directory. While there are technically 2 independent choices involved, the directory structure and the mechanism of Webpack configuration, for simplicity sake we'll assume that these choices go together.

Traditional React on Rails using the /client directory

Until version 9, all React on Rails apps used the /client directory for configuring React on Rails in terms of the configuration of Webpack and location of your JavaScript and Webpack files, including the node_modules directory. Version 9 changed the default to / for the node_modules location using this value in config/initializers/react_on_rails.rb: config.node_modules_location.

The ShakaCode Team recommends this approach for projects beyond the simplest cases as it provides the greatest transparency in your webpack and overall client-side setup. The big advantage to this is that almost everything within the /client directory will apply if you wish to convert your client-side code to a pure Single Page Application that runs without Rails. This allows you to google for how to do something with Webpack configuration and what applies to a non-Rails app will apply just as well to a React on Rails app.

The two best examples of this patten are the react-webpack-rails-tutorial and the integration test example in spec/dummy.

In this case, you don't need to understand the nuances of customization of your Wepback config via the Webpacker mechanism.

rails/webpacker Setup

Typical rails/webpacker apps have a standard directory structure as documented here. If you follow the steps in the the basic tutorial, you will see this pattern in action. In order to customize the Webpack configuration, you need to consult with the rails/webpacker Webpack configuration.

Version 9 made this the default for generated apps for 2 reasons:

1. It's less code to generate and thus less to explain.
2. rails/webpacker might be viewed as a convention in the Rails community.

The advantage of this is that there is very little code needed to get started and you don't need to understand really anything about Webpack customization. The big disadvantage to this is that you will need to learn the ins and outs of the rails/webpacker way to customize Webpack which differs from the plain Webpack way.

Overall, consider carefully if you prefer the rails/webpacker directory structure and Webpack configuration, over the placement of all client side files within the /client directory along with conventional Webpack configuration.

See Issue 982: Tutorial Generating Correct Project Structure? to discuss this issue.

Getting Started with an existing Rails app

For more detailed instructions on a fresh Rails app, see the React on Rails Basic Tutorial.

If you have rails-5 API only project, first convert the rails-5 API only app to rails app before getting started.

1. Add the following to your Gemfile and bundle install. We recommend fixing the version of React on Rails, as you will need to keep the exact version in sync with the version in your client/package.json file.

gem "react_on_rails", "11.0.0"
gem "webpacker", "~> 3.0"

2. Run the following 2 commands to install Webpacker with React:

   bundle exec rails webpacker:install
   bundle exec rails webpacker:install:react
   
   

3. Commit this to git (or else you cannot run the generator unless you pass the option --ignore-warnings).

4. See help for the generator:

rails generate react_on_rails:install --help

4. Run the generator with a simple "Hello World" example (more options below):

rails generate react_on_rails:install

5. Ensure that you have foreman installed: gem install foreman.

6. Start your Rails server:

foreman start -f Procfile.dev

8. Visit localhost:3000/hello_world. Note: foreman defaults to PORT 5000 unless you set the value of PORT in your environment. For example, you can export PORT=3000 to use the Rails default port of 3000. For the hello_world example this is already set.

Installation Overview

See the Installation Overview for a concise set summary of what's in a React on Rails installation.

Initializer Configuration

Configure the file config/initializers/react_on_rails.rb. You can adjust some necessary settings and defaults. See file docs/basics/configuration.md for documentation of all configuration options.

Including your React Component in your Rails Views

• Normal Mode (React component will be rendered on client):

  <%= react_component("HelloWorld", props: @some_props) %>

• Server-Side Rendering (React component is first rendered into HTML on the server):

  <%= react_component("HelloWorld", props: @some_props, prerender: true) %>

• The component_name parameter is a string matching the name you used to expose your React component globally. So, in the above examples, if you had a React component named "HelloWorld", you would register it with the following lines:

  import ReactOnRails from 'react-on-rails';
  import HelloWorld from './HelloWorld';
  ReactOnRails.register({ HelloWorld });

  Exposing your component in this way is how React on Rails is able to reference your component from a Rails view. You can expose as many components as you like, as long as their names do not collide. See below for the details of how you expose your components via the react_on_rails webpack configuration.

• @some_props can be either a hash or JSON string. This is an optional argument assuming you do not need to pass any options (if you want to pass options, such as prerender: true, but you do not want to pass any properties, simply pass an empty hash {}). This will make the data available in your component:

    # Rails View
    <%= react_component("HelloWorld", props: { name: "Stranger" }) %>

    // inside your React component
    this.props.name // "Stranger"

I18n

You can enable the i18n functionality with react-intl.

React on Rails provides an option for automatic conversions of Rails *.yml locale files into *.js files for react-intl.

See the How to add I18n for a summary of adding I18n.

Convert rails-5 API only app to rails app

1. Go to the directory where you created your app

rails new your-current-app-name

Rails will start creating the app and will skip the files you have already created. If there is some conflict then it will stop and you need to resolve it manually. be careful at this step as it might replace you current code in conflicted files.

2. Resolve conflicts

1. Press "d" to see the difference
2. If it is only adding lines then press "y" to continue
3. If it is removeing some of your code then press "n" and add all additions manually

3. Run bundle install and follow Getting started

NPM

All JavaScript in React On Rails is loaded from npm: react-on-rails. To manually install this (you did not use the generator), assuming you have a standard configuration, run this command (assuming you are in the directory where you have your node_modules):

yarn add react-on-rails --exact

That will install the latest version and update your package.json. NOTE: the --exact flag will ensure that you do not have a "~" or "^" for your react-on-rails version in your package.json.

Webpacker Configuration

React on Rails users should set configuration value compile to false, as React on Rails handles compilation for test and production environments.

How it Works

The generator installs your webpack files in the client folder. Foreman uses webpack to compile your code and output the bundled results to app/assets/webpack, which are then loaded by sprockets. These generated bundle files have been added to your .gitignore for your convenience.

Inside your Rails views, you can now use the react_component helper method provided by React on Rails. You can pass props directly to the react component helper. You can also initialize a Redux store with view or controller helper redux_store so that the store can be shared amongst multiple React components. See the docs for redux_store below and scan the code inside of the /spec/dummy sample app.

Client-Side Rendering vs. Server-Side Rendering

In most cases, you should use the prerender: false (default behavior) with the provided helper method to render the React component from your Rails views. In some cases, such as when SEO is vital, or many users will not have JavaScript enabled, you can enable server-rendering by passing prerender: true to your helper, or you can simply change the default in config/initializers/react_on_rails.

Now the server will interpret your JavaScript using ExecJS and pass the resulting HTML to the client. We recommend using mini_racer as ExecJS's runtime. The generator will automatically add it to your Gemfile for you (once we complete #501).

If you open the HTML source of any web page using React on Rails, you'll see the 3 parts of React on Rails rendering:

1. A script tag containing the properties of the React component, such as the registered name and any props. A JavaScript function runs after the page loads, using this data to build and initialize your React components.
2. The wrapper div <div id="HelloWorld-react-component-0"> specifies the div where to place the React rendering. It encloses the server-rendered HTML for the React component.
3. Additional JavaScript is placed to console-log any messages, such as server rendering errors. Note: these server side logs can be configured only to be sent to the server logs.

Note:

• If server rendering is not used (prerender: false), then the major difference is that the HTML rendered for the React component only contains the outer div: <div id="HelloWorld-react-component-0"/>. The first specification of the React component is just the same.

Building the Bundles

Each time you change your client code, you will need to re-generate the bundles (the webpack-created JavaScript files included in application.js). The included Foreman Procfile.dev will take care of this for you by starting a webpack process with the watch flag. This will watch your JavaScript code files for changes. Simply run foreman start -f Procfile.dev.

On production deployments that use asset precompilation, such as Heroku deployments, React on Rails, by default, will automatically run webpack to build your JavaScript bundles. You can see the source code for what gets added to your precompilation here. For more information on this topic, see the doc on Heroku deployment.

If you have used the provided generator, these bundles will automatically be added to your .gitignore to prevent extraneous noise from re-generated code in your pull requests. You will want to do this manually if you do not use the provided generator.

Generator Functions

You have 2 ways to specify your React components. You can either register the React component directly, or you can create a function that returns a React component. Creating a function has the following benefits:

1. You have access to the railsContext. See documentation for the railsContext in terms of why you might need it. You need a generator function to access the railsContext.
2. You can use the passed-in props to initialize a redux store or set up react-router.
3. You can return different components depending on what's in the props.

ReactOnRails will automatically detect a registered generator function. Thus, there is no difference between registering a React Component versus a "generator function."

Another reason to use a generator function is that sometimes in server rendering, specifically with React Router, you need to return the result of calling ReactDOMServer.renderToString(element). You can do this by returning an object with the following shape: { renderedHtml, redirectLocation, error }. Make sure you use this function with react_component_hash.

For server rendering, if you wish to return multiple HTML strings from a generator function, you may return an Object from your generator function with a single top level property of renderedHtml. Inside this Object, place a key called componentHtml, along with any other needed keys. An example scenario of this is when you are using side effects libraries like React Helmet. Your Ruby code will get this Object as a Hash containing keys componentHtml and any other custom keys that you added: { renderedHtml: { componentHtml, customKey1, customKey2} }

Rails Context and Generator Functions

When you use a "generator function" to create react components (or renderedHtml on the server), or you used shared redux stores, you get two params passed to your function that creates a React component:

1. props: Props that you pass in the view helper of either react_component or redux_store
2. railsContext: Rails contextual information, such as the current pathname. You can customize this in your config file. Note: The railsContext is not related to the concept of a "context" for React components.

This parameters (props and railsContext) will be the same regardless of either client or server side rendering, except for the key serverSide based on whether or not you are server rendering.

While you could manually configure your Rails code to pass the "railsContext information" with the rest of your "props", the railsContext is a convenience because it's passed consistently to all invocations of generator functions.

For example, suppose you create a "generator function" called MyAppComponent.

import React from 'react';
const MyAppComponent = (props, railsContext) => (
  <div>
    <p>props are: {JSON.stringify(props)}</p>
    <p>railsContext is: {JSON.stringify(railsContext)}
    </p>
  </div>
);
export default MyAppComponent;

Note: you will get a React browser console warning if you try to serverRender this since the value of serverSide will be different for server rendering.

So if you register your generator function MyAppComponent, it will get called like:

reactComponent = MyAppComponent(props, railsContext);

and, similarly, any redux store always initialized with 2 parameters:

reduxStore = MyReduxStore(props, railsContext);

Note: you never make these calls. React on Rails makes these calls when it does either client or server rendering. You will define functions that take these 2 params and return a React component or a Redux Store. Naturally, you do not have to use second parameter of the railsContext if you do not need it.

(Note: see below section on how to setup redux stores that allow multiple components to talk to the same store.)

The railsContext has: (see implementation in file react_on_rails_helper.rb, method rails_context for the definitive list).

  {
    railsEnv: Rails.env
    # URL settings
    href: request.original_url,
    location: "#{uri.path}#{uri.query.present? ? "?#{uri.query}": ""}",
    scheme: uri.scheme, # http
    host: uri.host, # foo.com
    port: uri.port,
    pathname: uri.path, # /posts
    search: uri.query, # id=30&limit=5

    # Other
    serverSide: boolean # Are we being called on the server or client? Note: if you conditionally
     # render something different on the server than the client, then React will only show the
     # server version!
  }

Why the railsContext is only passed to generator functions

There's no reason that the railsContext would ever get passed to your React component unless the value is explicitly put into the props used for rendering. If you create a react component, rather than a generator function, for use by React on Rails, then you get whatever props are passed in from the view helper, which does not include the Rails Context. It's trivial to wrap your component in a "generator function" to return a new component that takes both:

import React from 'react';
import AppComponent from './AppComponent';
const AppComponentWithRailsContext = (props, railsContext) => (
  <AppComponent {...{...props, railsContext}}/>
)
export default AppComponentWithRailsContext;

Consider this line in depth:

  <AppComponent {...{ ...props, railsContext }}/>

The outer {... is for the JSX spread operator for attributes and the innner {... is for the Spread in object literals.

Use Cases

Heroku Preboot Considerations

Heroku Preboot is a feature on Heroku that allows for faster deploy times. When you promote your staging app to production, Preboot simply switches the production server to point at the staging app's container. This means it can deploy much faster since it doesn't have to rebuild anything. However, this means that if you use the Define Plugin to provide the rails environment to your client code as a variable, that variable will erroneously still have a value of Staging instead of Production. The Rails.env provided at runtime in the railsContext is, however, accurate.

Needing the current URL path for server rendering

Suppose you want to display a nav bar with the current navigation link highlighted by the URL. When you server-render the code, your code will need to know the current URL/path. The new railsContext has this information. Your application will apply something like an "active" class on the server rendering.

Configuring different code for server side rendering

Suppose you want to turn off animation when doing server side rendering. The serverSide value is just what you need.

Customization of the rails_context

You can customize the values passed in the railsContext in your config/initializers/react_on_rails.rb. Here's how.

Set the config value for the rendering_extension:

  config.rendering_extension = RenderingExtension

Implement it like this above in the same file. Create a class method on the module called custom_context that takes the view_context for a param.

See spec/dummy/config/initializers/react_on_rails.rb for a detailed example.

module RenderingExtension

  # Return a Hash that contains custom values from the view context that will get merged with
  # the standard rails_context values and passed to all calls to generator functions used by the
  # react_component and redux_store view helpers
  def self.custom_context(view_context)
    {
     somethingUseful: view_context.session[:something_useful]
    }
  end
end

In this case, a prop and value for somethingUseful will go into the railsContext passed to all react_component and redux_store calls. You may set any values available in the view rendering context.

Globally Exposing Your React Components

Place your JavaScript code inside of the default app/javascript folder. Use modules just as you would when using webpack alone. The difference here is that instead of mounting React components directly to an element using React.render, you register your components to ReactOnRails and then mount them with helpers inside of your Rails views.

This is how to expose a component to the react_component view helper.

// app/javascript/packs/hello-world-bundle.js
import HelloWorld from '../components/HelloWorld';
import ReactOnRails from 'react-on-rails';
ReactOnRails.register({ HelloWorld });

Different Server-Side Rendering Code (and a Server Specific Bundle)

You may want different initialization for your server-rendered components. For example, if you have an animation that runs when a component is displayed, you might need to turn that off when server rendering. However, the railsContext will tell you if your JavaScript code is running client side or server side. So code that required a different server bundle previously may no longer require this. Note, check if window is defined has a similar effect.

If you want different code to run, you'd set up a separate webpack compilation file and you'd specify a different, server side entry file. ex. 'serverHelloWorld.jsx'. Note: you might be initializing HelloWorld with version specialized for server rendering.

Renderer Functions

A renderer function is a generator function that accepts three arguments: (props, railsContext, domNodeId) => { ... }. Instead of returning a React component, a renderer is responsible for calling ReactDOM.render to render a React component into the dom. Why would you want to call ReactDOM.render yourself? One possible use case is code splitting.

Renderer functions are not meant to be used on the server since there's no DOM on the server. Instead, use a generator function. Attempting to server render with a renderer function will cause an error.

ReactOnRails View Helpers API

Once the bundled files have been generated in your app/assets/webpack folder and you have registered your components, you will want to render these components on your Rails views using the included helper method, react_component.

react_component

react_component(component_name,
                props: {},
                prerender: nil,
                trace: nil,
                replay_console: nil,
                raise_on_prerender_error: nil,
                id: nil,
                html_options: {})

• component_name: Can be a React component, created using an ES6 class or a generator function that returns a React component (or, only on the server side, an object with shape { redirectLocation, error, renderedHtml }), or a "renderer function" that manually renders a React component to the dom (client side only). All options except props, id, html_options will inherit from your react_on_rails.rb initializer, as described here.

• general options:

  • props: Ruby Hash which contains the properties to pass to the react object, or a JSON string. If you pass a string, we'll escape it for you.
  • prerender: enable server-side rendering of a component. Set to false when debugging!
  • id: Id for the div, will be used to attach the React component. This will get assigned automatically if you do not provide an id. Must be unique.
  • html_options: Any other HTML options get placed on the added div for the component. For example, you can set a class (or inline style) on the outer div so that it behaves like a span, with the styling of display:inline-block.
  • trace: set to true to print additional debugging information in the browser. Defaults to true for development, off otherwise. Only on the client side will you will see the railsContext and your props.

• options if prerender (server rendering) is true:

  • replay_console: Default is true. False will disable echoing server-rendering logs to the browser. While this can make troubleshooting server rendering difficult, so long as you have the configuration of logging_on_server set to true, you'll still see the errors on the server.
  • logging_on_server: Default is true. True will log JS console messages and errors to the server.
  • raise_on_prerender_error: Default is false. True will throw an error on the server side rendering. Your controller will have to handle the error.

redux_store

Controller Extension

Include the module ReactOnRails::Controller in your controller, probably in ApplicationController. This will provide the following controller method, which you can call in your controller actions:

redux_store(store_name, props: {})

• store_name: A name for the store. You'll refer to this name in 2 places in your JavaScript:
  1. You'll call ReactOnRails.registerStore({storeName}) in the same place that you register your components.
  2. In your component definition, you'll call ReactOnRails.getStore('storeName') to get the hydrated Redux store to attach to your components.
• props: Named parameter props. ReactOnRails takes care of setting up the hydration of your store with props from the view.

For an example, see spec/dummy/app/controllers/pages_controller.rb. Note: this is preferable to using the equivalent view_helper redux_store in that you can be assured that the store is initialized before your components.

View Helper

redux_store(store_name, props: {})

This method has the same API as the controller extension. HOWEVER, we recommend the controller extension instead because the Rails executes the template code in the controller action's view file (erb, haml, slim, etc.) before the layout. So long as you call redux_store at the beginning of your action's view file, this will work. However, it's an easy mistake to put this call in the wrong place. Calling redux_store in the controller action ensures proper load order, regardless of where you call this in the controller action. Note: you won't know of this subtle ordering issue until you server render and you find that your store is not hydrated properly.

redux_store_hydration_data

Place this view helper (no parameters) at the end of your shared layout so ReactOnRails will render the redux store hydration data. Since we're going to be setting up the stores in the controllers, we need to know where on the view to put the client-side rendering of this hydration data, which is a hidden div with a matching class that contains a data props. For an example, see spec/dummy/app/views/layouts/application.html.erb.

Redux Store Notes

Note: you don't need to initialize your redux store. You can pass the props to your React component in a "generator function." However, consider using the redux_store helper for the two following use cases:

1. You want to have multiple React components accessing the same store at once.
2. You want to place the props to hydrate the client side stores at the very end of your HTML so that the browser can render all earlier HTML first. This is particularly useful if your props will be large.

server_render_js

server_render_js(js_expression, options = {})

• js_expression, like 2 + 3, and not a block of js code. If you have more than one line that needs to be executed, wrap it in an IIFE. JS exceptions will be caught, and console messages will be handled properly
• Currently, the only option you may pass is replay_console (boolean)

This is a helper method that takes any JavaScript expression and returns the output from evaluating it. If you have more than one line that needs to be executed, wrap it in an IIFE. JS exceptions will be caught and console messages handled properly.

Multiple React Components on a Page with One Store

You may wish to have 2 React components share the same the Redux store. For example, if your navbar is a React component, you may want it to use the same store as your component in the main area of the page. You may even want multiple React components in the main area, which allows for greater modularity. Also, you may want this to work with Turbolinks to minimize reloading the JavaScript. A good example of this would be something like a notifications counter in a header. As each notification is read in the body of the page, you would like to update the header. If both the header and body share the same Redux store, then this is trivial. Otherwise, we have to rely on other solutions, such as the header polling the server to see how many unread notifications exist.

Suppose the Redux store is called appStore, and you have 3 React components that each needs to connect to a store: NavbarApp, CommentsApp, and BlogsApp. I named them with App to indicate that they are the registered components.

You will need to make a function that can create the store you will be using for all components and register it via the registerStore method. Note: this is a storeCreator, meaning that it is a function that takes (props, location) and returns a store:

function appStore(props, railsContext) {
  // Create a hydrated redux store, using props and the railsContext (object with
  // Rails contextual information).
  return myAppStore;
}

ReactOnRails.registerStore({
  appStore
});

When registering your component with React on Rails, you can get the store via ReactOnRails.getStore:

// getStore will initialize the store if not already initialized, so creates or retrieves store
const appStore = ReactOnRails.getStore("appStore");
return (
  <Provider store={appStore}>
    <CommentsApp />
  </Provider>
);

From your Rails view, you can use the provided helper redux_store(store_name, props) to create a fresh version of the store (because it may already exist if you came from visiting a previous page). Note: for this example, since we're initializing this from the main layout, we're using a generic name of @react_props. In other words, the Rails controller would set @react_props to the properties to hydrate the Redux store.

app/views/layouts/application.html.erb

...
<%= redux_store("appStore", props: @react_props) %>;
<%= react_component("NavbarApp") %>
yield
...

Components are created as stateless function(al) components. Since you can pass in initial props via the helper redux_store, you do not need to pass any props directly to the component. Instead, the component hydrates by connecting to the store.

_comments.html.erb

<%= react_component("CommentsApp") %>

_blogs.html.erb

<%= react_component("BlogsApp") %>

Note: You will not be doing any partial updates to the Redux store when loading a new page. When the page content loads, React on Rails will rehydrate a new version of the store with whatever props are placed on the page.

ReactOnRails JavaScript API

See ReactOnRails JavaScript API.

Using Rails built-in CSRF protection in JavaScript

Rails has built-in protection for Cross-Site Request Forgery (CSRF), see Rails Documentation. To nicely utilize this feature in JavaScript requests, React on Rails provides two helpers that can be used as following for POST, PUT or DELETE requests:

import ReactOnRails from 'react-on-rails';

// reads from DOM csrf token generated by Rails in <%= csrf_meta_tags %>
csrfToken = ReactOnRails.authenticityToken();

// compose Rails specific request header as following { X-CSRF-Token: csrfToken, X-Requested-With: XMLHttpRequest }
header = ReactOnRails.authenticityHeaders(otherHeader);

If you are using jquery-ujs for AJAX calls, then these helpers are not needed because the jquery-ujs library updates header automatically, see jquery-ujs documentation.

React Router

React Router is supported, including server-side rendering! See:

1. React on Rails docs for react-router
2. Examples in spec/dummy/app/views/react_router and follow to the JavaScript code in the spec/dummy/client/app/startup/ServerRouterApp.jsx.
3. Code Splitting docs for information about how to set up code splitting for server rendered routes.

Caching and Performance

Consider fragment and http caching of pages that contain React on Rails components. See Caching and Performance for more details.

Deployment

• React on Rails puts the necessary precompile steps automatically in the rake precompile step. You can, however, disable this by setting certain values to nil in the config/initializers/react_on_rails.rb.
  • build_production_command: Set to nil to turn off the precompilation of the js assets.
  • config.symlink_non_digested_assets_regex: Default is nil, turning off the setup of non-js assets. This should be nil except when when using Sprockets rather than Webpacker.
• See the Heroku Deployment doc for specifics regarding Heroku. The information here should apply to other deployments.

Integration with Node.js for Server Rendering

If you want to use a node server for server rendering, get in touch. ShakaCode has built a premium Node rendering server for React on Rails.

Additional Documentation

Try out our Documentation Gitbook for improved readability & reference.

• Rails

  • Rails Assets
  • Rails Engine Integration
  • Rails View Rendering from Inline JavaScript
  • RSpec Configuration
  • Turbolinks

• Javascript

  • Node Dependencies, NPM, and Yarn
  • Babel
  • React Router
  • React & Redux
  • Webpack
  • Webpack Configuration
  • Webpack Cookbook
  • Developing with the Webpack Dev Server
  • Node Server Rendering
  • Server Rendering Tips
  • Code Splitting
  • AngularJS Integration and Migration to React on Rails
  • Webpack, the Asset Pipeline, and Using Assets w/ React

• Development

  • React on Rails Basic Installation Tutorial (live demo)
  • Installation Overview
  • Configuration
  • Migration from react-rails
  • Recommended Project Structure
  • Generator Tips
  • Hot Reloading of Assets For Rails Development
  • Heroku Deployment
  • Updating Dependencies
  • Caching and Performance

• API

  • JavaScript API
  • Ruby API
  • Setting up Hot Reloading during Rails Development, API docs

• Misc

  • Upgrading
  • Tips
  • Changelog
  • Projects
  • Shaka Code Style
  • React on Rails, Slides
  • Code of Conduct
  • The React on Rails Doctrine
  • React on Rails, 2000+ 🌟 Stars
  • Generator Testing
  • Linting
  • Releasing
  • CONTRIBUTING

Demos

• www.reactrails.com with the source at shakacode/react-webpack-rails-tutorial.
• spec app: Great simple examples used for our tests.

  cd spec/dummy
  bundle && yarn
  foreman start
  

Dependencies

• Ruby 2.1 or greater
• Rails 3.2 or greater
• Node 5.5 or greater

Contributing

Bug reports and pull requests are welcome. This project is intended to be a welcoming space for collaboration, and contributors are expected to adhere to our version of the Contributor Covenant Code of Conduct).

See Contributing to get started. See contribution help wanted.

License

The gem is available as open source under the terms of the MIT License.

Authors

The Shaka Code team!

The origins of the project began with the need to do a rich JavaScript interface for a ShakaCode's client. The choice to use Webpack and Rails is described in Fast Rich Client Rails Development With Webpack and the ES6 Transpiler.

The gem project started with Justin Gordon pairing with Samnang Chhun to figure out how to do server rendering with Webpack plus Rails. Alex Fedoseev then joined in. Rob Wise, Aaron Van Bokhoven, and Andy Wang did the bulk of the generators. Many others have contributed.

The gem was initially inspired by the react-rails gem.

Thanks!

The following companies support open source, and ShakaCode uses their products!

• JetBrains
• 

If you'd like to support React on Rails and have your company listed here, get in touch.

---

Thank you from Justin Gordon and ShakaCode

Thank you for considering using React on Rails.

We at ShakaCode are a small, boutique, remote-first application development company. We fund this project by:

• Providing priority support and training for anything related to React + Webpack + Rails in our Pro Support program.
• Building custom web and mobile (React Native) applications. We typically work with a technical founder or CTO and instantly provide a full development team including designers.
• Migrating Angular + Rails to React + Rails. You can see an example of React on Rails and our work converting Angular to React on Rails at egghead.io.
• Augmenting your team to get your product completed more efficiently and quickly.

My article "Why Hire ShakaCode?" provides additional details about our projects.

If any of this resonates with you, please email me, [email protected]. I offer a free half-hour project consultation, on anything from React on Rails to any aspect of web or mobile application development for both consumer and enterprise products.

We are currently looking to hire like-minded developers that wish to work on our projects, including Hawaii Chee.

Aloha and best wishes from Justin and the ShakaCode team!