title: How can I get an array with a nested array whose elements have a unique order?
body: <p>I have an array of arrays. How can I get an array with a nested array whose elements have a unique order?</p>
  <p>What I have:</p>
  <pre><code>[[1, 2], [1, 2, 3], [3, 4]]
  </code></pre>
  <p>Expected Output:</p>
  <pre><code>[[1, 2, 3], [3, 4]]
  </code></pre>
  <p>I think, that I can format to JSON, and get my result with filter and indexOf ,I have tried this:</p>
  <pre><code>var unique = x2.map(ar=&gt;JSON.stringify(ar).replace(/[\[\]']+/g,''))
    .filter((itm, idx, arr) =&gt; arr.indexOf(itm) === idx);
  </code></pre>