Mongoose transform toObject()

mongoose-transform.js

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/test');

const schema = new mongoose.Schema({
    _id: String,
    name: String,
    email: String,
    old: Number
});

if (!schema.options.toObject) schema.options.toObject = {};
schema.options.toObject.hide = '_id';
schema.options.toObject.transform = function (doc, ret, options) {
    if (options.hide) {
        options.hide.split(' ').forEach(function (prop) {
            delete ret[prop];
        });
    }
    return ret;
}

const User = mongoose.model('User', schema);

const doc = new User({
    _id: 'john',
    name: 'John Doe',
    email: 'john@doe.com',
    old: 31
});

console.log(doc.toObject());
console.log(doc.toObject({ hide: '_id old' }));
console.log(doc.toObject({ hide: '_id old', transform: true }));

Nice! Thank you