Using custom headers with Backbone.sync backbone restful token

a.js

/*
 * Using AMD/RequireJS
 *
 * The `auth` module handles OAuth and stores the
 * access token that needs to be sent in a header
 */
define(['api/auth'], function (auth) {
    'use strict';

    /*
     * Store a version of Backbone.sync to call from the
     * modified version we create
     */
    var backboneSync = Backbone.sync;

    Backbone.sync = function (method, model, options) {
        /*
         * The jQuery `ajax` method includes a 'headers' option
         * which lets you set any headers you like
         */
        options.headers = {
            /*
             * Set the 'Authorization' header and get the access
             * token from the `auth` module
             */
            'Authorization': 'Bearer ' + auth.getAccessToken()
        };

        /*
         * Call the stored original Backbone.sync method with
         * extra headers argument added
         */
        backboneSync(method, model, options);
    };
});