import { Injectable } from '@angular/core'; import { NavigationEnd, Router, } from '@angular/router'; @Injectable() export class RouterService { private previousUrl: string = undefined; private currentUrl: string = undefined; constructor(private router: Router) { this.currentUrl = this.router.url; router.events.subscribe((event) => { if (event instanceof NavigationEnd) { this.previousUrl = this.currentUrl; this.currentUrl = event.url; } }); } getPreviousUrl() { return this.previousUrl; } }