A leaner version of the "executeQueryAsync" method of the ClientContext class

SP.ClientContext.prototype.loadAsync

/*
 * USAGE
 *
 * var ctx = SP.ClientContext.get_current(); 
 *
 * var web = ctx.get_web();
 * var groups = web.get_siteGroups();
 *
 * ctx.loadAsync([web, groups], function (err, clientObjects) {
 *   if (err) {
 *      // do something about it
 *   }
 *
 *   console.log('Site "' + web.get_title() + '" has ' + groups.get_count() + ' groups');
 * });
 *
 * // query strings only work for collections up to now...
 * ctx.loadAsync(groups, 'Include(Id, Title)',function (err, clientObjects) {
 *   ...
 * });
 */

SP.ClientContext.prototype.loadAsync = function() {
    var object = arguments[0];
    var queryString;
    var callback;
    var that = this;
 
    function load(object, queryString) {
        if (queryString) {
            that.load(object, queryString);
        }
        else {
            that.load(object);
        }
    }
 
    if (typeof arguments[1] === 'string') {
        queryString = arguments[1];
        callback = arguments[2];
    }
    else {
        queryString = null;
        callback = arguments[1];
    }
 
    if (object instanceof Array) {
        for (var i = 0, len = object.length; i < len; i++) {
            load(object[i], queryString);
        }
    }
    else {
        load(object, queryString);
    }
 
    if (!callback) {
        return function(loadCallback) {
            that.executeQueryAsync(function() {
                loadCallback(null, object);
            },
            function(sender, args) {
                loadCallback(args);
            });
        };
    }
 
    this.executeQueryAsync(function() {
        callback(null, object);
    },
    function(sender, args) {
        callback(args);
    });
};