Ability to check for previous route with router.events.subscribe

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[ ] bug report => search github for a similar issue or PR before submitting
[X] feature request
[ ] support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

Current behavior The NavigationStart event object only returns the target url.

Expected/desired behavior Have the event also return the previous url

What is the motivation / use case for changing the behavior? I am having to call window.scrollTo(0,0) on every route call so that the new route doesn’t load at a random point on the page. But I don’t want this to happen on every route, and in some cases I want this to not happen when the routes are both children of the same component route.

Please tell us about your environment:

• Angular version: 2.0.0-rc.5
• Browser: [all ]
• Language: [all]

[jjlorenzo]

After following your recommendation. This is my working code.

import { Component }           from '@angular/core';
import { OnInit }              from '@angular/core';
import { Router }              from '@angular/router';
import { LocalStorageService } from 'angular-2-local-storage';


@Component({
  selector: 'app-root',
  template: `<router-outlet></router-outlet>`,
})
export class AppComponent implements OnInit {

  constructor(
    private router: Router,
    private storage: LocalStorageService,
  ) { }

  ngOnInit() {
    this.router.events
      .filter(e => e.constructor.name === 'RoutesRecognized')
      .pairwise()
      .subscribe((e: any[]) => {
        this.storage.set('referrer', e[0].urlAfterRedirects);
      });
  }

}

Thank you very much!

[DzmitryShylovich]

import { RoutesRecognized} from '@angular/router';
.filter(e => e instanceof RoutesRecognized)