title: How to know if array / object is empty after delete function?
body: <pre><code>var arr = [30];
  delete arr[0];
  if (arr.length == 0) {
  alert("empty");
  }
  </code></pre>
  
  <p>This code won't work only because of delete. 
  Is there an ultimate way to check if the array is empty no matter what?</p>
  
  <p>Thanks :)</p>