title: ExpressionChangedAfterItHasBeenCheckedException since Angular 2 beta
body: <p>I updated Angular 2 to beta.0. and use the firebaseevent pipe from: <a href="https://github.com/sararob/angular2base" rel="nofollow">https://github.com/sararob/angular2base</a></p>
  
  <pre><code>&lt;tr *ngFor="#t of DBSERVER | firebaseevent:'child_added'"&gt;
      &lt;td&gt;{{t.Message}}&lt;/td&gt;
      &lt;td&gt;{{t.Source}}&lt;/td&gt;
  &lt;/tr&gt;
  </code></pre>
  
  <p>Now I get the error: </p>
  
  <pre><code>Error: Expression 'DBSERVER | firebaseevent:'child_added' in Log@21:10' has changed after it was checked. Previous value: 'null'. Current value: 'undefined'
      at ExpressionChangedAfterItHasBeenCheckedException.BaseException [as constructor]
  </code></pre>
  
  <p>It worked with alpha46. Any ideas?</p>