Mongoose 8.8.2 returns back level MongoClient

[nigel-daniels]

Prerequisites

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

Mongoose version

8.8.2

Node.js version

v20.18.0

MongoDB server version

8.0.3

Typescript version (if applicable)

5.7.2

Description

I am using LangGraph which has a Mongo DB backed checkpoint memory, to connect it is looking for a MongoClient, so I have attempted to get the MongoClient object from Mongoose. This is the code I have so far:

import { MongoDBSaver } from '@langchain/langgraph-checkpoint-mongodb';
import { type MongoClient } from 'mongodb';
import mongoose from 'mongoose';

const client = /** @type {MongoClient} */ ( mongoose.connection.getClient() );

const mongoDBParams = {
	checkpointCollectionName: 'checkpoints',
	client: client,
    dbName: process.env.MONGO_NAME
}

const memory = new MongoDBSaver(mongoDBParams);

Unfortunately this throws the following error:

ERROR in /usr/local/quoterion/server/graphs/email_quote.ts
18:32-45
[tsl] ERROR in /usr/local/quoterion/server/graphs/email_quote.ts(18,33)
TS2345: Argument of type '{ checkpointCollectionName: string; client: mongoose.mongo.MongoClient; dbName: string; }' is not assignable to parameter of type 'MongoDBSaverParams'.
Types of property 'client' are incompatible.
Property 'timeoutMS' is missing in type 'import("/usr/local/quoterion/server/node_modules/mongoose/node_modules/mongodb/mongodb").MongoClient' but required in type 'import("/usr/local/quoterion/server/node_modules/mongodb/mongodb").MongoClient'.

It seems the 'MongoClientreturned is not compatible as its parameters are missing thetimoutMS`. In the Current MongoDB driver I can see this property but the version of the documentation on the Mongoose reference links to am older version that does not have this property (maybe a v4 version?). AFAIK LangGraph is using a v6.11.0 Mongo Driver.

Note in the rest of my code the mongoose driver is already up and running ok, hence I just thought I could get the underlying MongoClient.

Steps to Reproduce

Install LangGraph.JS, TypeScript, Mongoose and the MongoDB Types. Create a typescript file with the above and attempt to build.

Expected Behavior

This should build and run.

[vkarpov15]

Can you run npm list mongodb? It looks like you have 2 versions of the MongoDB node driver installed: 1 as a top level dep in package.json and one that Mongoose uses.

[nigel-daniels]

@vkarpov15 hi, I had installed a mongoldb library in order to try casting the type in case it was necessary. I removed the library I had installed and reverted the client assignment line to be:

const client = mongoose.connection.getClient();

When I run npm list mongodb I now see:

/Users/nigel/git/quoterion/server
├─┬ @langchain/[email protected]
│ └── [email protected]
├─┬ @langchain/[email protected]
│ └── [email protected] deduped
├─┬ [email protected]
│ └── [email protected] deduped
└─┬ [email protected]
  └── [email protected]

Regrettably the error still remains.

[vkarpov15]

Because it looks like your langchain and connect-mongo packages use [email protected], but Mongoose is still using [email protected]. We will ship Mongoose 8.9, which will have support for [email protected] in the next day or two. But in the meantime, you should add [email protected] as a top-level dependency, that should help fix this issue.