Queue ajax requests in Javascript

ajax-queue.js

    $(function() {
        var initialLoad = 0;
         
        var AjaxRequestsCompleted = (function() {
            var numRequestToComplete,
                requestsCompleted,
                callBacks;
    
            return function(options) {
                if (!options) options = {};
    
                numRequestToComplete = options.numRequest || 0;
                requestsCompleted = options.requestsCompleted || 0;
                callBacks = [];
                var fireCallbacks = function() {
                    for (var i = 0; i < callBacks.length; i++) callBacks[i]();
                };
                if (options.singleCallback) callBacks.push(options.singleCallback);
    
                this.addCallbackToQueue = function(isComplete, callback) {
                    if (isComplete) requestsCompleted++;
                    if (callback) callBacks.push(callback);
                    if (requestsCompleted === numRequestToComplete) fireCallbacks();
                };
                this.requestComplete = function(isComplete) {
                    if (isComplete) requestsCompleted++;
                    if (requestsCompleted === numRequestToComplete) fireCallbacks();
                };
                this.setCallback = function(callback) {
                    callBacks.push(callback);
                };
            };
        })();
        
    });

    // Example of queue implementation
    $("#TriggerId")
        .change(function(e) {
            e.preventDefault();
            var requestCallback = new AjaxRequestsCompleted({
                numRequest: 4
            });
            if (initialLoad === 1) {
                // Use this to check if the Ajax call has already run before
                // and implement anything
            }
            $.ajax({
                url: "url",
                data: {
                    format: 'json',
                    id: triggerId
                },
                type: "POST",
                success: function(data) {
                    requestCallback.addCallbackToQueue(true,
                        function() {
                            // Do something on success
                        });
                },
                error: function() {
                    console
                        .log("It's worse than that, he's dead Jim.");
                }
        });