Cacheing of deferred or non-deferred objects with deferred style wait queue

jquery.deferredCache.js

define(["jquery", "jquery.addTimeoutToDeferred"],
		function($, addTimeoutToDeferred) {   
    var cache = $.cache = Class.extend({
		cache: {},
		ready: {},
		init: function(args) {
			this.getput = this.putget;
		},
		contains: function(key) {
			return this.ready[key] !== undefined;
		},
		//
		// Returns a Promise.
		// If resolved, resolves with the value to get.
		// If a maxWait is given, rejects the promise after maxWait milliseconds.
		//
		get: function(key, maxWait) {
			if (this.ready[key] === undefined) {
				var dfd = $.Deferred();
				dfd.reject();
				return dfd.promise();
			} else if (maxWait) {
				return addTimeoutToDeferred(this.ready[key].promise(), maxWait);
			}
			return this.ready[key].promise();
		},
		//
		// Puts the value in the cache
		//
		put: function(key, value) {
			var oldVal = this.cache[key];
			this.cache[key] = value;
			if (this.ready[key] === undefined) {
				this.ready[key] = $.Deferred();
			}
			this.ready[key].resolve(value);
			return oldVal;
		},
		//
		// Returns the same as get().
		// loader may be a value or a function->Promise that resolves the value.
		// maxWait is optional
		// Constructor also aliases this function as getput.
		//
		putget: function(key, loader, maxWait) {
			if (this.ready[key] === undefined) {
				this.ready[key] = $.Deferred();
				if ($.isFunction(loader)) {
					var that = this;
					loader().done(function(value) {
						that.put(key, value);
					});
				} else {
					this.put(key, loader);
				}
			}
			return this.get(key, maxWait);
		}
	});
    return cache;
});