title: how to check if object is null or undefined in angular in ngIF condition
body: <p>I have this inside my code:</p>
  <pre><code> &lt;div *ngIf=&quot;(listCount$| async) &gt; 0 &quot;&gt;
  </code></pre>
  <p>but it won't pass the pipeline because it says</p>
  <pre><code>Object is possibly 'null' or 'undefined'.
  </code></pre>
  <p>in ts file:</p>
  <pre><code>readonly listCount$ = new BehaviorSubject&lt;number | undefined&gt;(undefined);
  </code></pre>
  <p>any help, can i do this in one line?</p>