title: How to calculate difference between two Maps in ImmutableJS?
body: <p>I have one parent Map and want to divide it with some logic.</p>
  
  <pre><code>let m = Map();
  let sub1 = m.filter((el) =&gt; el.isFiltered());
  </code></pre>
  
  <p>How can I get the rest of the Map? I know that I can invert condition inside filter, but I want to know if there is some method which is analogue to <a href="http://underscorejs.org/#difference" rel="nofollow">_.difference in underscore</a>?</p>