RequireJS for Rails
Integrates RequireJS into the Rails 3+ Asset Pipeline.
UPGRADE NOTES: Users upgrading within the 0.x series should read the Changes section for relevant usage changes. We're pushing hard to 1.0, when the configuration and setup details will be declared stable. Until that time expect some bumps as things bake out.
Usage
-
Add this to your Rails app's
Gemfile:gem 'requirejs-rails' -
Remove all Sprockets directives such as
//= require jqueryfromapplication.jsand elsewhere. Instead establish JavaScript dependencies using AMD-styledefine()andrequire()calls. -
Use
requirejs_include_tagat the top-level of your app's layout(s). Other modules will be pulled in dynamically byrequire.jsin development and for production builds optimized byr.js. Here's a basicapp/views/layouts/application.html.erbmodified forrequirejs-rails:<!DOCTYPE html> <html> <head> <title>Frobnitz Online</title> <%= stylesheet_link_tag "application" %> <%= requirejs_include_tag "application" %> <%= csrf_meta_tags %> <meta charset="utf-8"> </head> <body> <%= yield %> </body> </html>
-
Organize your JavaScript or CoffeeScript code into modules using
define():# app/assets/javascripts/views/tweet_view.js.coffee define ['backbone'], (Backbone) -> class TweetView extends Backbone.View # ...
-
Instantiate your app using
require()from a top-level module such asapplication.js:# app/assets/javascripts/application.js.coffee require ['jquery', 'backbone', 'TheApp'], ($, Backbone, TheApp) -> # Start up the app once the DOM is ready $ -> window.App = new TheApp() Backbone.history.start pushState: true window.App.start()
-
When ready, build your assets for production deployment as usual.
requirejs-railsdefaults to a single-file build ofapplication.js. Additional modules and r.js layered builds may be specified viaconfig/requirejs.yml; see the Configuration section below.rake assets:precompile
Configuration
The Basics
Configuration lives in config/requirejs.yml. These values are inspected and
used by requirejs-rails and passed along as configuration for require.js and
r.js. The default configuration declares application.js as the sole
top-level module. This can be overridden by creating
a config/requirejs.yml, such as:
modules:
- name: 'mytoplevel'You may pass in require.js config options as needed. For example, to add path parameters:
paths:
d3: "d3/d3"
"d3.time": "d3/d3.time"Layered builds
Only modules specified in the configuration will be created as build artifacts
by r.js. Layered r.js
builds be
configured like so:
modules:
- name: 'appcommon'
- name: 'page1'
exclude: ['appcommon']
- name: 'page2'
exclude: ['appcommon']
priority: ['appcommon']In this example, only modules page1 and page2 are intended for direct
loading via requirejs_include_tag. The appcommon module contains
dependencies shared by the per-page modules. As a guideline, each module in
the configuration should be referenced by one of:
- A
requirejs_include_tagin a template - Pulled in via a dynamic
require()call. Modules which are solely referenced by a dynamicrequire()call (i.e. a call not optimized by r.js) must be specified in the modules section in order to produce a correct build. - Be a common library module like
appcommon, listed in thepriorityconfig option.
Almond support
This gem supports single-file builds with
almond. Use the following setting in
application.rb to enable it:
config.requirejs.loader = :almondAlmond builds have the restriction that there must be exactly one modules entry in
requirejs.yml. Typically the wrap option will be used to create a self-contained build:
modules:
- name: 'main'
wrap: trueBuild-time asset filter
The requirejs-rails build process uses the Asset Pipeline to assemble assets
for the r.js build. By default, assets ending in .js, .html, and .txt
will be made available to the build. If you have other asset suffixes to
include, use the logical_path_patterns config setting to add them.
For example, if your templates all end in .templ like so...
// in app/assets/javascripts/myapp.js
define(function (require) {
var stuff = require('text!stuff.templ');
// ...
});... then this config setting will ensure they're picked up in the build:
# in config/application.rb
config.requirejs.logical_path_patterns += [/\.templ$/]Advanced features
Additional data attributes
requirejs_include_tag accepts an optional block which should return a hash.
This hash will be used to populate additional data-... attributes like so:
<%= requirejs_include_tag "page1" do |controller|
{ 'foo' => controller.foo,
'bar' => controller.bar
}
end
%>This will generate a script tag like so:
<script data-main="/assets/page1.js" data-foo="..." data-bar="..." src="/assets/require.js"></script>
External domain (CDN) support
There are two ways in which requirejs-rails supports the use of different domains for serving built JavaScript modules, as is the case when using a CDN.
-
URLs in paths config in
requirejs.yml:If requirejs-rails encounters an URL as the right-hand side of a paths configuration, it will correctly emit that as
"empty:"during the build process so that r.js will do the right thing.Example:
paths: jquery: "https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"
-
Deploying all requirejs-rails assets to a CDN:
In
config/environments/production.rb(or another environment) set the run_config as follows:config.requirejs.run_config['baseUrl'] = 'http://mycdn.example.com/12345abc/assets'
The
asset_syncgem is one tool that can be used to deploy your built assets to a CDN (S3, in this case).
Troubleshooting
Avoid config.assets.precompile
Don't set config.assets.precompile to reference any of your AMD module code.
Avoid it altogether, except to reference non-AMD code that you're loading via
javascript_include_tag, and which is never referenced by the AMD codebase.
Using AMD libraries
I currently recommend placing your AMD libraries into
vendor/assets/javascripts. The needs of a few specific libraries are
discussed below.
jQuery
jQuery users must use jQuery 1.7 or later (jquery-rails >= 1.0.17) to use it as an AMD module with RequireJS. To use jQuery in a module:
# app/assets/javascripts/hello.js
define ['jquery'], ($) ->
(id) ->
$(id).append('<div>hello!</div>')Backbone.js
Backbone 0.9.x doesn't support AMD natively. I recommend the amdjs fork of Backbone which adds AMD support and actively tracks mainline.
Underscore.js
Underscore 1.3.x likewise doesn't have AMD support. Again, see the amdjs fork of Underscore.
0.x API Changes
Usage changes that may break functionality for those upgrading along the 0.x series are documented here. See the Changelog for the full list of feature additions, bugfixes, etc.
v0.9.2
- Support for Rails 4.
v0.9.0
- The upgrade to RequireJS and r.js 2.0 includes changes that will break some apps.
v0.5.1
-
requirejs_include_tagnow generates a data-main attribute if given an argument, ala:<%= requirejs_include_tag "application" %>
This usage is preferred to using a separate
javascript_include_tag, which will produce errors from require.js or r.js if the included script uses define anonymously, or not at all.
v0.5.0
application.jsis configured as the default top-level module for r.js builds.- It is no longer necessary or desirable to specify
baseUrlexplicitly in the configuration. - Users should migrate application configuration previously in
application.js(alarequire.config(...)) toconfig/requirejs.yml
TODOs
Please check out our GitHub issues page to see what's upcoming and to file feature requests and bug reports.
Copyright 2011-2014 John Whitley. See the file MIT-LICENSE for terms.