Prototype YUI Loader Stand Alone

This repo contains a little build script to create a stand alone version of the latest YUI 3.5.0pr2 Loader.

It includes:

yui-core
get
loader-base

Currently it's 225k raw, 43k minimized and 16K minned and gzipped.

This can easily be worked on once I modularize the YUI core more so it doesn't contain things that are not needed all the time.

Example here: http://dl.dropbox.com/u/5669457/loader-alone/test/index.html

Notice that YUI is not loaded on the page, it's there but wrapped up in an anonymous function.

Usage

Everything you need to use Loader is already on this repo, the build directory contains a loader.js and loader-min.js

var loader = new YUILoader({
    root: '',
    base: '',
    groups: {
        local: {
            modules: {
                foo: {
                    type: 'js',
                    path: 'foo/foo.js',
                    requires: [ 'bar', 'baz' ]
                },
                baz: 'path/to/baz.js',
                bar: 'bar.js',
                somecss: 'my/css/files.css'
            }
        }
    },
    require: [ 'foo', 'somecss' ]
});

loader.load(function(e) {
    log('All items have been loaded..', e);
});

Concept

The concept here is pretty simple, it concats yui-core, get & loader-base into a single file. Then it wraps that code with something like this:

(function() {
    var YUI;
    var exports = {};

    //Concatted Source here

    YUI.Env.core.push('loader-base');

    var Y = YUI();

    window.YUILoader = Y.Loader;

    Y.Loader.expose = Y.Loader.prototype.expose = function(cb) {
        YUI.Env.core = [].concat(YUI.Env.core, ['loader-yui3', 'features', 'intl-base']);
        if (!window.YUI) { //Have to globally expose now for YUI.add calls.
            window.YUI = YUI;
        }
        Y.use('loader-yui3', 'features', 'intl-base', function() {
            delete YUI.Env._loader;
            delete YUI.Env._renderedMods;
            
            cb(window.YUI);
        });
    }


}());

This wrapping code is boilerplate for forcing YUI to attach itself to the exports object. Then augment the core to autoload the loader-base module, then expose a global YUILoader var. Then it adds a expose method as a static method and into Loader's prototype. This method is used to expose the exported YUI module and fetch the other parts of YUI needed to make it fully functional (features, loader metadata, intl-base).

Exposing YUI

This prototype scopes the global YUI onto a local exports object, holding it in a private scope so that it only exposes Loader globally. Maybe you want to load simple modules up front, but later on in your code you need other things from the library. That's where expose comes in. Simply call YUILoader.expose(cb) with a callback and Loader will fetch the parts of YUI it needs to complete the transaction and fire your callback when all the dependencies are complete.

YUILoader.expose(function() {
    YUI().use('node', fn);
});