Angular - What is the meanings of module.id in component?
<p>In an Angular app, I have seen that <code>@Component</code> has property <code>moduleId</code>. What does it mean? </p>

<p>And when <code>module.id</code> is not defined anywhere, the app still works. How can it still work?</p>

<pre class="lang-javascript prettyprint-override"><code>@Component({
  moduleId: module.id,
  selector: 'ng-app',
  templateUrl: 'app.component.html',
  styleUrls: ['app.component.css'],
  directives: [AppComponent]
});
</code></pre>