$window.Firebase不是构造函数错误消息，Firebase未加载

我已经“正确”地设置了一切。使用AngularFire1版本1的内容不适用于AngularFire1版本2。我收到一条错误消息，上面说：

$window.Firebase is not a constructor

守则：

我做对了的事情：

• 包括firebase.js和angularfire.js
• 将“firebase”添加到应用程序包含的库中
• 使用我的firebase配置文件的地址创建了firebase配置文件
• 创建了位于app/scripts/services/firebaseref.js的firebase参考文件

  'use strict';
  
  /**
   * @ngdoc overview
   * @name angularFireDemoApp
   * @description
   * # angularFireDemoApp
   *
   * Main module of the application.
   */
  angular
    .module('angularFireDemoApp', [
      'ngAnimate',
      'ngCookies',
      'ngResource',
      'ngRoute',
      'ngSanitize',
      'ngTouch',
      'firebase'
    ])
    .config(function ($routeProvider) {
      $routeProvider
        .when('/', {
          templateUrl: 'views/main.html',
          controller: 'MainCtrl',
          controllerAs: 'main'
        })
        .when('/about', {
          templateUrl: 'views/about.html',
          controller: 'AboutCtrl',
          controllerAs: 'about'
        })
        .otherwise({
          redirectTo: '/'
        });
    });
  

  'use strict';
  
  /**
   * @ngdoc service
   * @name angularFireDemoApp.FirebaseRef
   * @description
   * # FirebaseRef
   * Factory in the angularFireDemoApp.
   */
  angular.module('angularFireDemoApp')
      .factory('FirebaseRef', function ($window, FirebaseConfig) {
          return new $window.Firebase(FirebaseConfig);
      });
  

  'use strict';
  
  /**
   * @ngdoc service
   * @name angularFireDemoApp.FirebaseConfig
   * @description
   * # FirebaseConfig
   * Constant in the angularFireDemoApp.
   */
  angular.module('angularFireDemoApp')
    .constant('FirebaseConfig', 'https://enviedsolutionsangularfire.firebaseio.com');