title: JSON.stringify returning []
body: <p>Why would <code>JSON.stringify()</code> return:</p>
  
  <pre><code>[]
  </code></pre>
  
  <p>The same happens with jQuery: <code>$.JSON.encode()</code></p>
  
  <p>What could cause this? I am passing in a simple array of objects, where each object has string properties. I have looped through and alerted each objects properties and all looks fine, but for some reason both the encode methods are returning <code>[]</code>.</p>