Angular 2 typescript error when using subscribe fu

问题:

I am trying to set up authentication for my Angular 2 app with the new router. Someone suggested to try the following:

constructor (private _router: Router) {} 

ngOnInit(){
  this._router.subscribe(
    next => {
      if (!userIsLoggedInOrWhatever) {
        this._router.navigate(['Login']);
      }
    }
  )    
}

This problem however is that this results in the typescript error

(app.component.ts(47,22): error TS2339: Property 'subscribe' does not exist on type 'Router'.

This is strange because the documentation clearly shows that a Router object does have this function. I am able to call other functions like router.navigate(['/url']). Do you guys have an idea what could be the problem?

回答1:

new router

constructor(router:Router) {
  router.events.subscribe(event:Event => {
    if(event instanceof NavigationStart) {
    }
    // NavigationEnd
    // NavigationCancel
    // NavigationError
    // RoutesRecognized
  })
}

original

The Router class has an EventEmitter changes you can subscribe to:

ngOnInit(){
  this._router.changes.subscribe(
    next => {
      if (!userIsLoggedInOrWhatever) {
        this._router.navigate(['Login']);
      }
    }
  )    
}

For how to get the previous route see How to detect a route change in Angular 2? (pairwise())