title: Angular Check if property exists within template
body: <p>I have an HTML table and its rows are being generated by an <code>ngFor</code> loop. I need to add a class to these table cells if some criteria is met.</p>
  
  <p>The issue is that that I need to check if the value of a property is empty AND see if the property even if the property even exists in the first place.</p>
  
  <pre><code>&lt;tbody&gt;
   &lt;tr *ngFor="let e of (modalData.compareData | filter: filterString)"&gt;
    &lt;td [class.success]="e.NewRuleVersionID === ''"&gt;{{ (e.OldRuleVersionID ? e.OldRuleVersionID  : 'New') }}&lt;/td&gt;
    &lt;td [class.success]="e.NewRuleVersionID === ''"&gt;{{ (e.OldOutcome ? e.OldOutcome : 'New') }}&lt;/td&gt;
    &lt;td [class.danger]="e.OldRuleVersionID === ''"&gt;{{ (e.NewRuleVersionID ? e.NewRuleVersionID : 'Removed') }}&lt;/td&gt;
    &lt;td [class.danger]="e.OldRuleVersionID === ''"&gt;{{ (e.NewOutcome ? e.NewOutcome : 'Removed') }}&lt;/td&gt;
   &lt;/tr&gt;
  &lt;/tbody&gt;
  </code></pre>
  
  <p>In the above code, I am adding a class to those cells if the value doesn't exist. However, there are some records where that property doesn't exist at all. Can this be checked inline within the template so I can account for it?</p>