NodeJS and MongoDB - Array of ObjectId how to return Objects

Question

I have in a collection an reference array of ObjectId. And I want to return the object's data linked with those Ids in the json response.

retrieveFromUser: function( req, res ) {
    var user_id =   req.params.user_id;
    User.findById( user_id, function( err, user ) {
        if( err ) {
            res.send( 404, "Unable to find user");
        } else {
            // This returns the array but I want the objects data
            return res.json( user.constructions );
        }
    });
}

How can I do that ?
thanks a lot !

Answer 1

Try to use populate() method

retrieveFromUser: function( req, res ) {
 var user_id =   req.params.user_id;
    User.findOne({ _id: user_id }).populate('constructions').exec(function( err, user ) {
        if( err ) {
            res.send( 404, "Unable to find user");
        } else {
            // This returns the array but I want the objects data
            return res.json( user.constructions );
        }
    });
}