重構 Observable 以避免類型斷言錯誤

Question

我正在為CanDeactive Guard 編寫單元測試，並且我的 jasmine 規范出現類型斷言錯誤：

// Mock Guard defined at top of spec file
class MockGuardComponent implements ComponentCanDeactivate {
  // Set this value to the value you want to mock being returned from 
GuardedComponent
  returnValue: boolean | Observable<boolean>;

  canDeactivate(): boolean | Observable<boolean> {
    return this.returnValue || this.openConfirmDialog();
  }
}

it('will not route if guarded and user rejected the dialog', () => {
    // Mock the behavior of the MockGuardedComponent
    const subject$ = new Subject<boolean>();
    mockGuardComponent.returnValue = subject$.asObservable();
    const canDeactivate$ = <Observable<boolean>>(
      service.canDeactivate(mockGuardComponent)
    );
    canDeactivate$.subscribe((deactivate) => {
      // this is the real test
      expect(deactivate).toBeFalsy();
    });
    // Emulate the reject
    subject$.next(false);

}。 );

該規范正確地引發了以下錯誤：

Type assertion using the '<>' syntax is forbidden. Use the 'as' syntax instead.

它不喜歡這部分：

<Observable<boolean>>

我知道使用BehaviorSubject可能會更好，但我已經在使用Subject ，所以我不確定如何結合我在這里所做的事情。 有小費嗎？

Answer 1

改變

const canDeactivate$ = <Observable<boolean>>(
      service.canDeactivate(mockGuardComponent)
    );

至

const canDeactivate$ = service.canDeactivate(mockGuardComponent) as Observable<boolean>;