title: Get keys of a document in MongoDB Document
body: <p>Is there any way to get the list of keys of a particular document in MongoDB other than iterate through the document?</p>
  
  <p>i.e I want to get the keys for the document returned by </p>
  
  <pre><code>db.users.find({username:'xyz@abc.com})
  </code></pre>
  
  <p>Are there any inline commands.If not,can anybody give an idea on how to do? </p>