title: How to check whether <ng-content> is empty? (in Angular 2+ till now)
body: <p>Suppose I have a component:</p>
  
  <pre class="lang-js prettyprint-override"><code>@Component({
      selector: 'MyContainer',
      template: `
      &lt;div class="container"&gt;
          &lt;!-- some html skipped --&gt;
          &lt;ng-content&gt;&lt;/ng-content&gt;
          &lt;span *ngIf="????"&gt;Display this if ng-content is empty!&lt;/span&gt;
          &lt;!-- some html skipped --&gt;
      &lt;/div&gt;`
  })
  export class MyContainer {
  }
  </code></pre>
  
  <p>Now, I would like to display some default content if <code>&lt;ng-content&gt;</code> for this component is empty. Is there an easy way to do this without accessing the DOM directly?</p>