title: Mongodb query to Count days between two dates of each document
body: <p><strong>Sample Docs :</strong></p>
  
  <pre><code>{
      "_id" : ObjectId("5e7331614dd99d1a30143a58"),
      "status" : "rejected",
      "from" : ISODate("2020-03-17T08:46:02.552Z"),
      "to" : ISODate("2020-03-18T08:46:07.124Z")
  },
  {
      "_id" : ObjectId("5e7331614dd99d1a30143a58"),
      "status" : "rejected",
      "from" : ISODate("2020-03-02T08:08:32.819Z"),
      "to" : ISODate("2020-03-05T08:08:37.125Z"),
  }
  </code></pre>
  
  <p>I am new to mongodb, I want to count the number of days between dates (to and from fields) of each document where status is equal to 'rejected'</p>