An interface for asynchronously loading the Google Maps API and queuing callbacks.

maps-queue.js

define(function() {

    return {

        /**
         * Queue
         * @type {Array}
         */
        queue: [],

        /**
         * Init
         */
        init: function() {
            var self = this;
            var script = document.createElement('script');
            script.src = 'https://maps.googleapis.com/maps/api/js?sensor=false&callback=mapsQueueCallback';
            document.head.appendChild(script);

            window.mapsQueueCallback = function() {
                self.execute();
            };
        },

        /**
         * Add
         * @param {Function} callback
         */
        add: function(callback) {
            if ( ! window.mapsQueueCallback) {
                this.init();
            }

            this.queue.push(callback);
        },

        /**
         * Execute
         */
        execute: function() {
            while (this.queue.length) {
                this.queue.pop().call(window);
            }

            if (window.mapsQueueCallback) {
                delete window.mapsQueueCallback;
            }
        }
    };

});