title: Is the double asterisk ** a valid JavaScript operator?
body: <p>I solved a kata on CodeWars and was looking through some of the other solutions when I came across the double asterisk to signify to the power of. I have done some research and can see that this is a valid operator in python but can see nothing about it in JavaScript documentation.</p>
  
  <pre><code>var findNb = m =&gt;
  {
    var n = Math.floor((4*m)**.25);
    var sum = x =&gt; (x*(x+1)/2)**2;
    return sum(n) == m ? n : -1;
  }
  </code></pre>
  
  <p>Yet when I run this solution on CodeWars, it seems to work. I am wondering if this is new in ES6, although I have found nothing about it.</p>