<!-- #docregion -->
<h3>Heroes:</h3>
<ul>
  <li *ngFor="let hero of heroes">
    {{ hero.name }}
  </li>
</ul>
New Hero:
<input #newHero />
<button (click)="addHero(newHero.value); newHero.value=''">
  Add Hero
</button>
<div class="error" *ngIf="errorMessage">{{errorMessage}}</div>
