Monkey patching of ObjectId, but still undefined?

[nicolas-urbantz]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

7.6.4

Node.js version

20

MongoDB server version

5.9.1

Typescript version (if applicable)

5.1.6

Description

Hello!

We are upgrading an old codebase from mongoose 5 to 7. I see that mongoose is monkey patching the "native" ObjectId by adding a _id attribute... But I'm wondering if the type is correct because in the code, I can see:

declare module 'bson' {
  interface ObjectId {
    /** Mongoose automatically adds a conveniency "_id" getter on the base ObjectId class */
    _id: this;
  }
}

while, in reality, it's undefined (see steps to reproduce).

I saw that issue, but it doesn't answer my question :/

Steps to Reproduce

This is my unit test:

import { ObjectId as MongoDBObjectId } from 'mongodb';
test('_id is undefined', () => {
	const objectId = new MongoDBObjectId('5b348a71fe5e561dd1c70628');
	expect(objectId._id).toBeUndefined();
});

Expected Behavior

It passes, but shouldn't it fail? Or shouldn't the monkey patch say that _id could be undefined?

[vkarpov15]

_id won't be added as a property on MongoDBObjectId unless you import Mongoose. So your unit test failing looks expected, unless there's an import 'mongoose' somewhere.

[nicolas-urbantz]

Hey, thanks for your quick answer... I tried to run this then, and it passes:

• One test with the "native" ObjectId => Stil no _id
• One test with the ObjectId from mongoose => _id is present

import { ObjectId as MongoDBObjectId } from 'mongodb';
import mongoose from 'mongoose';

describe('Native ObjectId', () => {
	test('_id is undefined', () => {
		const objectId = new MongoDBObjectId('5b348a71fe5e561dd1c70628');
		expect(objectId._id).toBeUndefined();
	});
});

describe('mongoose ObjectId', () => {
	test('_id is undefined', () => {
		const objectId = new mongoose.Types.ObjectId(
			'5b348a71fe5e561dd1c70628'
		);
		expect(objectId._id).toBe(objectId);
	});
});

[github-actions]

This issue is stale because it has been open 14 days with no activity. Remove stale label or comment or this will be closed in 5 days

[nicolas-urbantz]

Up :) I add some clarification, but I don't know if/how I can remove the label @vkarpov15

[IslandRhythms]

Please modify the script to demonstrate your issue.

const mongoose = require('mongoose');
const { ObjectId } = require('mongodb');
let MongoDBObjectID = ObjectId;

const mongodbId = new MongoDBObjectID('5b348a71fe5e561dd1c70628');
console.log('what is mongodbId', mongodbId);

const mongooseObjectId = new mongoose.Types.ObjectId('5b348a71fe5e561dd1c70628');
console.log('what is mongoose object id', mongooseObjectId);
console.log(mongooseObjectId._id);

[vkarpov15]

I modified @IslandRhythms ' script slightly, but still not able to repro this issue:

const mongoose = require('mongoose');
const { ObjectId } = require('mongodb');
let MongoDBObjectID = ObjectId;

const mongodbId = new MongoDBObjectID('5b348a71fe5e561dd1c70628');
console.log('what is mongodbId', mongodbId._id);

const mongooseObjectId = new mongoose.Types.ObjectId('5b348a71fe5e561dd1c70628');
console.log('what is mongoose ObjectId', mongooseObjectId._id);

Output:

$ node gh-14154.js 
what is mongodbId new ObjectId('5b348a71fe5e561dd1c70628')
what is mongoose ObjectId new ObjectId('5b348a71fe5e561dd1c70628')

@nicolas-urbantz can you please run npm run list | grep "mongo" and provide the output? I suspect you have a different version of the MongoDB Node driver than Mongoose.

[nicolas-urbantz]

Thanks, I'll have a look tomorrow 🫶

[nicolas-urbantz]

@vkarpov15 , you are right I think, we have another version.

I copy/paste your script and here is my output:

what is mongodbId undefined
what is mongoose ObjectId new ObjectId("5b348a71fe5e561dd1c70628")

Output of npm list:

├── mongodb@5.9.1
├── mongoose@7.6.4

I see that mongoose is using 5.9.0 in the lock. Do you recommend to not install mongodb "manually", but then use the "mongodb of mongoose", if I want to call mongodb directly (without mongoose)?

[vkarpov15]

@nicolas-urbantz yes I'd recommend you use require('mongoose').mongo, or match your version of the mongodb package to Mongoose's.

[nicolas-urbantz]

Make sense!

Thank you for your time 🙏