app.component.html

<h3>Angular 練習</h3>

<ul>
  <li><a [routerLink]="path.home">練習一</a></li>
  <li><a [routerLink]="path.p2">練習二</a></li>
  <li><a [routerLink]="path.p3">練習三</a></li>
</ul>

<router-outlet></router-outlet>