Claudiu S Claudiu S - 1 year ago 210
Node.js Question

Mongoose query: remove "_id" attribute, keep virtual attribute "id" in results

I am running an Express.js app, and I have the following setup:


var schemaOptions = {
toJSON: {
virtuals: true
toObject: {
virtuals: true

var modelSchema = new mongoose.Schema({
name : { type: String, required: true }

}, schemaOptions);

modelSchema.virtual('id').get(function() { return this._id; });


exports.getModel = function(req, res) {
Model.find().select('name').exec(function(err,model) {
if (err) {
return res.status(500).json({errors:err, message: 'Internal server error'});
return res.status(200).json({model: model});

The result of the above query would be something like:

{ "_id":"dakjdjkakda", "name":"MontyPython", "id":"dakjdjkakda" }

because of the Virtual attribute I defined in the modelSchema.

If I change the query select statement to:

Model.find().select('-_id name').exec(function(err,model) {}

The result would be:

{"name":"MontyPython", "id":null }

I believe this happens because the Virtual attribute points to the _id attribute.

My question is, how can remove the _id attribute in the query, but keep the id alias I created?

Answer Source

You cannot do that. MongoDB requires _id attribute to be present as per documentation.

Your option is to use virtual attribute as in your example and perhaps $project to hide the field in the query result.

Otherwise, your mongo driver, such as Mongoose, should be able to hide or rename the desired field or attribute.

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