Mongoose/Mongodb: Exclude fields from populated query data

Question

Mongoose/Mongodb: Exclude fields from populated query data

I use the following mongoose query in a MEAN-environment to find and output a particular author and his corresponding books.

Author
.findOne({personcode: code})
.select('-_id')
.select('-__v')
.populate('bookids') //referencing to book documents in another collection (->array of bookids)
.select('-_id') //this doens't affect the data coming from the bookids-documents
.select('-__v') //this doens't affect the data coming from the bookids-documents
.exec(function (err, data) {
   //foo
});

I would also like to exclude the "_id" and "__v" fields from the populated data coming from the external documents. How can that be achieved?

javascript
node.js
mongodb
mongoose

Answer 1

The second parameter of populate is a field selection string, so you can do this as:

Author
  .findOne({personcode: code})
  .select('-_id -__v')
  .populate('bookids', '-_id -__v')
  .exec(function (err, data) {
    //foo
});

Note that you should combine your field selections into a single string.