title: Is it possible to check if the object is available before Destructuring?
body: <p>I have an object of values to <code>Destructure</code>, But before doing so i would like to check if the object is available,</p>
  
  <pre><code>const  { contactno, contactemail } =  this.props.app.user;
  </code></pre>
  
  <p>In this case the object <code>user</code> is not available always, Due to this I am getting following error,</p>
  
  <pre><code>TypeError: Cannot read property 'contactno' of undefined.
  </code></pre>
  
  <p>Hence, Is there nay way to check if the object is available before <code>Destructure</code>?</p>