Lazyload Google Maps Angular Service

deferMaps.js

/* 
usage: 
Initializer.mapsInitialized.then(function(){
  initMap(); // do stuff with maps
});
*/
angular.module('ngApp', []).
factory('Initializer', function($window,$q){
    var asyncUrl = '//maps.googleapis.com/maps/api/js?callback=',
    mapsDefer = $q.defer();
    $window.googleMapsInitialized = mapsDefer.resolve;
    var asyncLoad = function(asyncUrl, callbackName) {
    	var script = document.createElement('script');
    	script.src = asyncUrl + callbackName;
    	document.body.appendChild(script);
    };
    asyncLoad(asyncUrl, 'googleMapsInitialized');
    return {
      mapsInitialized : mapsDefer.promise
    };
})