Mongoose/Mongodb: Exclude fields from populated query data

Question

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?

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.