// See https://github.com/gnarf/jquery-ajaxQueue for license and copyright

(function($) {

// jQuery on an empty object, we are going to use this as our Queue
var ajaxQueue = $({});

$.ajaxQueue = function( ajaxOpts ) {
    var jqXHR,
        dfd = $.Deferred(),
        promise = dfd.promise();

    // run the actual query
    function doRequest( next ) {
        jqXHR = $.ajax( ajaxOpts );
        jqXHR.done( dfd.resolve )
            .fail( dfd.reject )
            .then( next, next );
    }

    // queue our ajax request
    ajaxQueue.queue( doRequest );

    // add the abort method
    promise.abort = function( statusText ) {

        // proxy abort to the jqXHR if it is active
        if ( jqXHR ) {
            return jqXHR.abort( statusText );
        }

        // if there wasn't already a jqXHR we need to remove from queue
        var queue = ajaxQueue.queue(),
            index = $.inArray( doRequest, queue );

        if ( index > -1 ) {
            queue.splice( index, 1 );
        }

        // and then reject the deferred
        dfd.rejectWith( ajaxOpts.context || ajaxOpts, [ promise, statusText, "" ] );
        return promise;
    };

    return promise;
};

})(jQuery);