title: How do I construct a Set with an Array
body: <p>I am playing with <code>Set</code> in Node.JS v0.11.3 and the <code>--harmony</code> flag. The API works fine, I can <code>add</code>, <code>remove</code>, <code>clear</code>, etc. I have however not been able to initialise a set with an array. I have tried (as prompted by <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set" rel="nofollow">the MDN page</a>)</p>
  
  <pre><code>var mySet = new Set([1, 1, 2]);
  </code></pre>
  
  <p>How can I convert an array to a set? Is MDN outdated? Has Node.JS simply not implemented the feature?</p>