Angular 2：从 MockBackend 静态解析符号值时遇到错误

我是 Angular2 的新手，正在尝试运行它tutorial http://jasonwatmore.com/post/2016/08/16/angular-2-jwt-authentication-example-tutorial。它使用一个fakeBackendProvide使用来模拟后端调用MockBackend.

fackBackend 的逻辑如下：export let fakeBackendProvider = {}

index.ts类有助于导出fackBackendProvider用一行：export * from './fake-backend';

app.module.ts看起来像这样：

providers: [
    AuthGuard,
    AuthenticationService,
    UserService,

    //fake backend providers
    fakeBackendProvider,
    MockBackend,
    BaseRequestOptions
  ],

我收到此错误消息：ERROR in Error encountered resolving symbol values statically. Function calls are not supported. Consider replacing the function or lambda with a reference to an exported function (position 7:15 in the original .ts file), resolving symbol fakeBackendProvider in /Users/hyadav/Documents/hp-app/src/app/helpers/fake-backend.ts, resolving symbol fakeBackendProvider in /Users/hyadav/Documents/hp-app/src/app/helpers/index.ts, resolving symbol AppModule in /Users/hyadav/Documents/hp-app/src/app/app.module.ts, resolving symbol AppModule in /Users/hyadav/Documents/hp-app/src/app/app.module.ts

不知道出了什么问题。

其余代码可以在这里找到：Github https://github.com/himanshuy/hiringplus-ui/tree/master/src/app/helpers

我在同一个教程中遇到了同样的问题。我所做的只是从 lambda 表达式创建一个新函数，然后在 fakeBackendProvider 的 useFactory 中调用它。

export function mockBackEndFactory(backend: MockBackend, options: BaseRequestOptions, realBackend: XHRBackend) { ... }

export let fakeBackendProvider = {
  provide: Http,
  deps: [MockBackend, BaseRequestOptions, XHRBackend],
  useFactory: mockBackEndFactory
};

这是我修改的 fake-backend.ts 文件的链接：https://github.com/cealmees/Angular2-training/blob/master/src/app/entities/login/helpers/fake-backend.ts https://github.com/cealmees/Angular2-training/blob/master/src/app/entities/login/helpers/fake-backend.ts