title: Javascript new Date() returns different date
body: <p>I did create a date object out of '31/12/2018':</p>
  
  <pre><code>new Date('2018', '12', '31')
  </code></pre>
  
  <p>It does however create something completely different that I would expect.</p>
  
  <pre><code>Date {Thu Jan 31 2019 00:00:00 GMT+0100 (Central European Standard Time)}
  </code></pre>
  
  <p>What's happening?</p>