title: If else shorthand inside array .push()
body: <p>Why I can do <code>if else shorthand</code> inside <code>.push()</code> function ? like</p>
  
  <pre><code>var arr = [];
  arr.push(test||null);
  // nothing
  </code></pre>
  
  <p>But</p>
  
  <pre><code>var arr = [];
  var test = test||null;
  arr.push(test);
  // [null]
  </code></pre>
  
  <p>I need to insert <code>null</code> if variable is undefined.</p>
  
  <p>Why I cant use <code>test||null</code> inside <code>.push()</code> function ?</p>