$.eachDeferred

$.eachDeferred

(function ($, window, document, undefined) {
 	$.extend({
		/*
		* Iterates over elms array/collection using deferred callbacks.
		* the function assigned for iterator should return promise.
		* resolved promises notify the main deferred, so we can track each loop result.
		* returns promise.
		*/
		eachDeferred: function (elms, c) {

			if (!$.isArray(elms)) {
				elms = $.makeArray(elms);
			}

			var that = this,
				dfd = $.Deferred(),
				i = elms.length,
				next = function () {
					setTimeout(function () { elms.length ? cb(elms.shift()) : dfd.resolve(that); }, 0);
				},
				cb = function (elm) {
					$.when(c.call(elm, i - elms.length, elm)).always(function (result) {
						dfd.notify(result);
						next();
					});
				};

			next();

			return dfd.promise();
		}
	});
 }(jQuery, window, document));