Example of using require.js to load jQuery from a CDN

This example shows one way to load jQuery and jQuery plugins with require.js. In this example, we have modified the plugins to be wrapped in a define(), rather than using the shim configuration. If you'd like to see how to load jQuery plugins that do not call define, without modifying the source, see the example with shim config

In this example, we set the path of jQuery to point to a google-hosted CDN. That can benefit users, who might already have the file in their browser cache, and therefore don't have to download it again.

Please note that in order to be able to load an asset from a CDN in the built files, all the plugins that needs that asset as a dependency have to call define().

###Project structure

tools/

• build.js
• r.js

www/app.html

www/js/

• app.js
• lib/
  • jquery.alpha.js
  • jquery.beta.js
  • require.js
• app/
  • main.js

###How it's set up The main file of this setup is www/js/app.js. It is loaded from app.html by this line:

<script data-main="js/app" src="js/lib/require.js"></script>

App.js is mainly about path configuration. We point out the special paths to our app code, and to the google CDN for jQuery. Finally, our main code is loaded at the bottom of the file:

requirejs.config({
    "baseUrl": "js/lib",
    "paths": {
      "app": "../app",
      "jquery": "//ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min"
    }
});

// Load the main app module to start the app
requirejs(["app/main"]);

App/main.js is where the app logic is:

define(["jquery", "jquery.alpha", "jquery.beta"], function($) {
    //the jquery.alpha.js and jquery.beta.js plugins have been loaded.
    $(function() {
        $('body').alpha().beta();
    });
});

###How to see it in action

Just serve up the www/ folder using any web server you'd like. To get you set up quickly, we include a node.js static file server in tools/. Start the server by typing node tools/server.js from the command line, and then go to localhost:8888/www/app.html in your browser.

###How to optimize it using r.js To use the optimizer, you need node.js or Java 6 installed. These instructions assume Node is being used. See the Optimization page for more information.

r.js and a build configuration is included in the tools/ folder. To build, navigate to tools/ and type node r.js -o build.js. You will find the built product in the www-build folder. If you serve that directory instead, you can see in the network panel of the web developer tools that the files aren't loaded separately any more.

Because jQuery is loaded from a network path, r.js will automatically exclude jQuery from the built product, and keep loading it from the CDN.