How to configure Mongoose with an already existing Mongo connection

Question

I have an app that is already working with the native Node Mongo driver (v3.0). I'm now trying to slowly implement Mongoose in order to make the app easier to maintain. I would like to do this in a gradual way so I rewrote all the user related operations with Mongoose and the rest like it was before. I noticed that my app now creates two connections to my Mongo db. This is clearly because Mongoose knows nothing about my existing connection.

I would like to handle connecting and disconnecting to Mongo myself and give Mongoose a reference to the already existing connection but I can't find anything like this in the docs.

Is this even possible or will I need two different connections until my app is fully rewritten to use Mongoose exclusively?

EDIT: My app is being run as an AWS Lambda function which has to connect and disconnect to mongo on every request so having two concurrent connections per request is effectively halving my mongo db available connections. That's why I'm concerned about having an extra connection.

Answer 1

Turns out the answer to this is to do it the other way around. Just connect to Mongoose and then grab the connection.

let mongoConnection = mongoose.connection.client