title: Set of Tuples in JavaScript?
body: <p>What is the best way to implement a <code>Set</code> of coordinates in JavaScript? I would like to be able to do things like:</p>
  <pre><code>let s=new Set();
  s.add([1,1]);
  if (s.has([1,1])) // false, since these are different arrays
  </code></pre>
  <p>The above doesn't work, since the <code>Set</code> is storing a reference to the array instead of the contents.</p>