Async Image Preloader Using Promises AMD

imageLoader.js

define(['jquery'], function($) {
    'use strict';

    return function(urlArray) {
        return $.when.apply($, urlArray.map(function(url) {
            if(url) {
                var $imgDeferred = new $.Deferred();

                setTimeout(function() {
                    var imageTag = new Image();

                    imageTag.onload = $imgDeferred.resolve;
                    imageTag.onerror = $imgDeferred.reject;

                    imageTag.src = url;
                }, 0);

                return $imgDeferred.promise();
            }
        }));
    };
});