angular - 运行 karma 测试时出现错误无法读取 null 的属性 'extras'

Question

我制作了一个组件，并使用以下代码从 route 获取一些数据。当我尝试 ng test 时出现错误:

TypeError: Cannot read property 'extras' of null

我应该在此组件的规范文件中导入什么来读取“状态”？在我的规范文件中，我添加了 import { RouterTestingModule } from '@angular/router/testing' 但仍然不起作用；

const navigation = this.router.getCurrentNavigation();
        const state = navigation.extras.state;
        console.log(state);

Answer 1

@Component({
  selector: 'app-root',
  template: `<pre>{{ state$ | async | json }}</pre>`,
})
export class AppComponent implements OnInit {
  private state$: Observable<object>;

  constructor(public router: Router) { }

  ngOnInit() {
    this.state$ =  this.router.events.pipe(
      filter(e => e instanceof NavigationStart),
      map(() => this.router.getCurrentNavigation().extras.state)
    )
  }
}

更多信息:Passing Data between Routes in Angular