title: Get key from value with this node.js dictionary
body: <p>I am using this node.js collection module. 
  <a href="http://www.collectionsjs.com/" rel="nofollow">http://www.collectionsjs.com/</a></p>
  
  <p>I would like to get the key from value inside a dictionary. Here is my code;</p>
  
  <pre><code>"use strict";
  var Dict = require("collections/dict");
  
  var Data_type = new Dict(
      {
          "00": "DATA_NOT",
          "01": "DATA_SENSOR",
          "02": "DATA_SENSOR2",
          "03": "DATA_SENSOR3",
      });
  </code></pre>
  
  <p>Getting the value from key is easy. <code>Data_type.get("00");</code> will return <code>DATA_NOT</code>. However, I am encountering problem in getting the key from value. Preferably, I would like to do something like  <code>Data_type.getKey("DATA_NOT");</code> and have it return <code>"00"</code>. Any other methods are welcomed.</p>