angular detect router change

1import { Component } from '@angular/core'; 
2import { Router, Event, NavigationStart, NavigationEnd, NavigationError } from '@angular/router';
3
4@Component({
5    selector: 'app-root',
6    template: `<router-outlet></router-outlet>`
7})
8export class AppComponent {
9
10    constructor(private router: Router) {
11
12        this.router.events.subscribe((event: Event) => {
13            if (event instanceof NavigationStart) {
14                // Show loading indicator
15            }
16
17            if (event instanceof NavigationEnd) {
18                // Hide loading indicator
19            }
20
21            if (event instanceof NavigationError) {
22                // Hide loading indicator
23
24                // Present error to user
25                console.log(event.error);
26            }
27        });
28
29   }
30}