mongoose find populate example
Example 1: mongoose populate filter
Story.
find(...).
populate({
path: 'fans',
// filtering field, you can use mongoDB syntax
match: { age: { $gte: 21 } },
// Explicitly exclude `_id`, see http://bit.ly/2aEfTdB
select: 'name -_id'
}).
exec();
Example 2: populate mongoose array select
User.findById(id).populate({
path: 'contacts.user',
select: 'email'
})