title: Object to json string in node.js
body: <p>I have a problem with node.js to object to json string</p>
  
  <pre><code>var chat = {};
  chat.messages = [];
  chat.messages['en'] = [];
  chat.messages['fr'] = [];
  console.log(chat.messages)
  console.log(JSON.stringify(chat.messages));
  </code></pre>
  
  <p>I got</p>
  
  <pre><code>[ en: [], fr: [] ]
  []
  </code></pre>
  
  <p>I don't know why this is not correctly convert</p>