title: Nativescript Angular async pipe in listview not showing elements
body: <p>I'm trying to get a basic <code>ListView</code> to be populated by a <code>BehaviourSubject</code> using the <code>async</code> pipe. </p>
  
  <p>The markup code is very simple :</p>
  
  <blockquote>
    <p>component.html</p>
  </blockquote>
  
  <pre><code>&lt;ListView [items]="$photos | async" separatorColor="transparent"&gt;
      &lt;ng-template let-item="item"&gt;
          &lt;Label&gt;{{ item.upid }}&lt;/Label&gt;
      &lt;/ng-template&gt;
  &lt;/ListView&gt;
  </code></pre>
  
  <p>Next in the component I use the <code>push</code> <code>ChangeDetectionStrategy</code>,subscribe to the service responsible to data retrieval and populate the <code>BehaviourSubject</code>.
  Here is the relevant code : </p>
  
  <blockquote>
    <p>component.ts</p>
  </blockquote>
  
  <pre><code>user: ComunicationModels.UserDto = {};
    photos: Array&lt;ComunicationModels.PhotoDto&gt; = [];
    $photos: BehaviorSubject&lt;Array&lt;ComunicationModels.PhotoDto&gt;&gt;;
  
    constructor(...) {
        this.$photos = new BehaviorSubject([]);
        this.user.photos.forEach(
          (idPhoto) =&gt; {
            this.postService.getPhoto(idPhoto)
              .subscribe((p) =&gt; {
                this.photos.push(p);
                this.$photos.next([...this.photos]);
                // console.dir(this.$photos.value); -&gt; This shows correct information
              });
          });
    }
  </code></pre>
  
  <p>I don't get errors, but my listview is completely empty not showing up any items... what am I missing?</p>