Store a YUI instance and re-use it.

// How awful is this approach? Really awful? Not awful?
// Cuz it seems not awful, and actually really convenient.
// Note how MyComponent has a single instance of YUI(),
// but without having to wrap the whole thing in the YUI call.
// This means that MyComponent can be extended later on,
// and still use the same single instance of YUI.

MyComponent = (function () {
	var myYUI = null
	var load = function (fn) {
		if (myYUI && fn) return fn();
		myYUI || YUI().use(
			'log', 'lang', 'node', 'event', 'dom', 'json',
			function (y) {
				myYUI = y;
				return fn();
			});
		return false;
	};
	var doSomething = function (asdf) {
		if (!myYUI) throw new Error("Not loaded yet!");
		// do something with the myYUI instance.
	};
	return { load:load, doSomething:doSomething };
})();

MyComponent.load(function () {
	MyComponent.doSomething("foo");
});