loginUser(e) {
  e.preventDefault();
  let username = e.target.elements[0].value;
  let password = e.target.elements[1].value;

  if(username == 'test' && password == 'test'){
    this.service.login().subscribe(userIsLoggedIn =>
      this.router.navigate(['admin/overview']));
  }
}

{
  path: 'admin',
  component: AdminLoginComponent,
  data: {title: 'Admin'}
},
{
  path: 'admin/overview',
  component: AdminOverviewComponent,
  canActivate: [AuthGuard],
  data: {title: 'Overview'}
}