title: Typescript - specify type for destructed variable alias
body: <pre><code>ngOnChanges(changes: SimpleChanges) {
      const {previousValue: prevDate, currentValue: currDate}: SimpleChange = changes.dateFilter;
  }
  </code></pre>
  
  <p>In the above code snippet I want to specify type <code>DateFilter</code> to the <code>prevDate</code> and <code>currDate</code> variables. How can I achieve that?
  I tried like <code>&lt;DateFilter&gt;prevDate</code> and is not working.</p>