角度2:从MockBackend静态解析符号值时遇到错误 [英] Angular 2: Error encountered resolving symbol values statically from MockBackend

问题描述

我是Angular2的新手，正在尝试运行此 Github

解决方案

我在同一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中的useFactory内部调用它.

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

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

这是我修改过的fake-backend.ts文件的链接:tutorial. It uses a fakeBackendProvide to simulate backend calls using MockBackend.

Logic for fackBackend goes like this: export let fakeBackendProvider = {}

index.ts class helps to export the fackBackendProvider with one line: export * from './fake-backend';

app.module.ts looks like this:

providers: [
    AuthGuard,
    AuthenticationService,
    UserService,

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

I am getting this error message: 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

No idea what is going wrong.

Rest of the code, can be found here: Github

解决方案

I had the same issue with the same tutorial. What I did was just create a new function from the lambda expression and then just invoked it inside the useFactory in fakeBackendProvider.

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

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

Here's the link for fake-backend.ts file I modified: https://github.com/cealmees/Angular2-training/blob/master/src/app/entities/login/helpers/fake-backend.ts

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