title: Array of Array, JSON.stringify() giving empty array instead of entire object
body: <p>Here's my array (from Chrome console):</p>
  
  <p><img src="https://i.stack.imgur.com/RjCE6.png" alt="array in Chrome console"></p>
  
  <p>Here's the pertinent part of code:</p>
  
  <pre><code>console.log(hours);
  var data = JSON.stringify(hours);
  console.log(data);
  </code></pre>
  
  <p>In Chrome's console I get <code>[]</code> from the last line. I should get <code>{'Mon':{...}...}</code></p>
  
  <p>Here is the minimal amount of JavaScript to reproduce the issue:</p>
  
  <pre><code>var test = [];
  test["11h30"] = "15h00"
  test["18h30"] = "21h30"
  console.log(test);    
  console.log(JSON.stringify(test)); // outputs []
  </code></pre>
  
  <p>I tried some other stuff like
  <a href="https://stackoverflow.com/questions/2295496/convert-array-to-json">Convert array to JSON</a> or <a href="https://stackoverflow.com/questions/19970301/convert-javascript-object-or-array-to-json-for-ajax-data">Convert javascript object or array to json for ajax data</a> but the problem remains.</p>