Class CompletesBeforeEmitting

packages/router/test/integration/guards.spec.ts:82–97

    describe('CanActivate', () => {
      describe('guard completes before emitting a value', () => {
        @Injectable({providedIn: 'root'})
        class CompletesBeforeEmitting {
          private subject$ = new Subject<boolean>();

          constructor(destroyRef: DestroyRef) {
            destroyRef.onDestroy(() => this.subject$.complete());
          }

          // Note that this is a simple illustrative case of when an observable
          // completes without emitting a value. In a real-world scenario, this
          // might represent an HTTP request that never emits before the app is
          // destroyed and then completes when the app is destroyed.
          canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) {
            return this.subject$;
          }
        }

        it('should not thrown an unhandled promise rejection', async () => {
          const router = TestBed.inject(Router);