Once you have been using the YUI JavaScript framework for a little while, you’ll inevitably need to write your own custom modules. For me, I started creating lots and lots of widgets and needed to figure out how to properly modularize everything. The documentation for creating modules using YUI.add is good, and it got me up and running quickly. So far, so good.

Armed with a handful of widgets in proper YUI modules, I needed a way to actually register them with my YUI instances in order to use them. Again, the docs for the YUI Loader ably pointed the way, with one tiny exception.

The examples shown all look like this:

YUI({
   modules:  {
       "foo_widget": {
           fullpath: "/js/foo_widget.js",
           requires: ["widget"]
           // ... other configuration ...
       },
       // ... other modules ...
   }
}).use("foo_widget", function(Y) {
    // Do stuff...
});

Of course, this works, but it becomes a pain to repeat all my custom module information on each page where they’re used (for each YUI instance, really). The documentation doesn’t readily show (at least, I wasn’t able to find it) how you can set all this information once for your entire application.

Digging around on the forums, however, turned up the YUI_config object. Basically, this is the same map that you would otherwise pass to the YUI object when you want to create a new instance. Sticking it in YUI_config makes it automatically available whenever you create a new instance. What I’ve done is create a file that defines a YUI_config object for my application (loading it up with all my module definition information), and I include that in my pages. It’s dead simple:

YUI_config = {
    modules: {
        "foo_widget": {
            fullpath: "/js/foo_widget.js",
            requires: ["widget"]
        },
        // ... etc.
    },
};

Now, I can reference foo_widget just like I would any other YUI module:

YUI().use("foo_widget",
    function(Y){
        // do interesting things with foo_widget here...
    });

Problem solved.