title: How to get all empty values with null in document.find() mongodb along with existing values
body: <p>I am querying and retrieving all data from a collection to json . The collection has 50 fields.But all 50 fields are not filled in the records. When I retrieve the record to json ,I am getting only existing fields .. For example if name is not there in the document,it wont be there.. I want it to come as {'name':'null'}.</p>
  
  <p>As there are 50 fields,it is difficult to do a manual check..</p>