title: Composite key representation in javascript
body: <p>I have a C# dictionary with a composite key:</p>
  
  <pre><code>IDictionary&lt;Tuple&lt;int, int?&gt;, MyObject&gt; MyObjects
  </code></pre>
  
  <p>What is the best way to represent this data structure in Javascript?</p>
  
  <p>I'd like to be able to access my objects like:</p>
  
  <pre><code>var obj = MyObjects[[3,2]];
  </code></pre>
  
  <p>or </p>
  
  <pre><code>var obj = MyObjects[[3,null]];
  </code></pre>