[TypeScript] watch().on doesn't have correct type on callback, so can't access fullDocument

[tomups]

Prerequisites

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

Mongoose version

7.0.2 (but happening since 6.4.0, with the switch to mongodb driver 4.7.0)

Node.js version

19.8.1

MongoDB server version

6.0.4

Typescript version (if applicable)

5.0.2

Description

watch().on is returning the generic ChangeStreamDocument<T> as argument for the on callback, which doesn't include fullDocument and other properties from other types of specialized ChangeStreamDocument types like ChangeStreamInsertDocument or ChangeStreamUpdateDocument that were introduced in mongodb driver 4.6.0.

I suppose it's because the current type for watch() accepts only 1 argument, but since mongodb 4.6.0, watch type requires two arguments to be able to provide the specialized return types:

https://github.com/mongodb/node-mongodb-native/releases/tag/v4.6.0

See current docs https://mongodb.github.io/node-mongodb-native/5.1/classes/Collection.html#watch

Steps to Reproduce

model.watch<Schema>([], { fullDocument: "updateLookup" }).on("change", (change) => {
  console.log(change.fullDocument);
});

Will give a TypeScript error: Property 'fullDocument' does not exist on type 'ChangeStreamDocument<Schema>'.

Expected Behavior

Being able to call watch with specialized type, like:

model
  .watch<Schema, ChangeStreamInsertDocument<Schema> | ChangeStreamUpdateDocument<Schema>>([], {
    fullDocument: "updateLookup",
  })
  .on("change", (change) => {
    console.log(change.fullDocument);
  });

So the change argument of the on callback has the correct type, to for example be able to access fullDocument.

Workaround

As a workaround, I'm setting the type of the on parameter explicitly to the specialized types I need:

model
  .watch<Schema>([], { fullDocument: "updateLookup" })
  .on("change", (change: ChangeStreamInsertDocument<Schema> | ChangeStreamUpdateDocument<Schema>) => {
    console.log(change.fullDocument);
  });

But I think it makes more sense to align the current mongoose's watch to how it is in the current mongodb driver.