title: Getting nested values in Immutable.js
body: <p>According to the docs here: <a href="https://facebook.github.io/immutable-js/docs/#/Map/getIn">https://facebook.github.io/immutable-js/docs/#/Map/getIn</a></p>
  
  <p>I should be able to get the deeply nested value by providing an array for the <code>keyPath</code> argument. This is what I've done, however I'm getting <code>undefined</code> as the return value.</p>
  
  <p><a href="http://jsfiddle.net/srxv4mwu/">http://jsfiddle.net/srxv4mwu/</a></p>
  
  <pre><code>var obj = Immutable.Map({categories: {1: 'a', 2: 'b'}});
  var output = obj.getIn(['categories', 1]);
  alert(output);
  </code></pre>
  
  <p>What am I doing wrong?</p>