How to count records with one distinct field in mongoose?

Question

While exploring mongoose for nodejs I ran into the problem of needing to know the amount of user in my collection:

My collection has records, each record has a user

Answer 1

If you just want get the number of queried collections, you can use this:

Record.find()
      .distinct('user_id')
      .count(function (err, count) {
          //The number of unique users is 'count'
      });