angular navigate using component
//ng new routing-app --routing
//ng generate component first
//ng generate component second
    
import { Router } from '@angular/router';
...
export class AboutUserComponent implements OnInit {
  user: User;
  constructor(
    private route: ActivatedRoute, 
    private service: UserService,
    private router: Router
  ) {}
  ngOnInit() {
    // grab the current username
    let username = this.route.snapshot.params['username'];
    this.service.getUser(username).then(user => this.user = user);
  }
  goBack() {
    this.router.navigate(['/about']);
  }
}
