title: Check Element not in array in java script?
body: <p>Hi I am New to JS i trying below code</p>
  
  <pre><code>a=[0,1,3]
  if (2 in a){ console.log(a)}
  </code></pre>
  
  <p>in above code i am checking element is available are not. but in above case 2 is not in array but condition show true why?</p>
  
  <p>i know we can check condition like this a.includes(2) 
  why in above case showing true?</p>
  
  <p>Thanks Advance.  </p>