title: comparing ECMA6 sets for equality
body: <p>How do you compare two javascript sets? I tried using <code>==</code> and <code>===</code> but both return false.</p>
  
  <pre><code>a = new Set([1,2,3]);
  b = new Set([1,3,2]);
  a == b; //=&gt; false
  a === b; //=&gt; false
  </code></pre>
  
  <p>These two sets are equivalent, because by definition, <a href="https://en.wikipedia.org/wiki/Set_(abstract_data_type)" rel="noreferrer">sets do not have order</a> (at least not usually). I've looked at <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set" rel="noreferrer">the documentation for Set on MDN</a> and found nothing useful. Anyone know how to do this?</p>