TypeScript - Should LeanDocument<T> include _id?

[Bene-Graham]

I am wondering if LeanDocument should include _id? I am migrating form the @type/mongoose to the built in types but _id is missing.

In the below example _id is print out.

import { Schema, model, connect, LeanDocument } from 'mongoose';

interface User {
    name: string;
    email: string;
    avatar?: string;
}

const schema = new Schema<User>({
    name: { type: String, required: true },
    email: { type: String, required: true },
    avatar: String
});

const UserModel = model<User>('User', schema);

run().catch(err => console.log(err));

async function run(): Promise<void> {
    // 4. Connect to MongoDB
    await connect('CONNECTION STRING HERE');

    await UserModel.create({
        email: "abc@abc.com",
        name: "test"
    });

    const docs = await UserModel.find().lean().exec();

    for(const doc of docs) {
        // @ts-expect-error typing should have _id?????
        console.log(doc._id);
    }
}

What is the expected behavior?

typescript: 4.4.4
node: 16.x
mongoose: 6.1.2

[IslandRhythms]

the _id is printing

[Bene-Graham]

Yes it is printing, but the intelisence says there is no property _id.

If you look at how LeanDocument is defined

  export type LeanDocument<T> = Omit<_LeanDocument<T>, Exclude<keyof Document, '_id' | 'id' | '__v'> | '$isSingleNested'>;

you can see that it is excluding _id from the type.

[Bene-Graham]

digging a bit deeper, lean() does not return a LeanDoument type in my example.

lean<LeanResultType = RawDocType extends Document ? LeanDocumentOrArray<ResultType> : LeanDocumentOrArrayWithRawType<ResultType, RawDocType>>(val?: boolean | any): QueryWithHelpers<LeanResultType, DocType, THelpers, RawDocType>;

lean seems to be taking the path with LeanDocumentOrArrayWithRawType

  export type LeanDocumentOrArrayWithRawType<T, RawDocType> = 0 extends (1 & T) ? T :
    T extends unknown[] ? RawDocType[] :
    T extends Document ? RawDocType :
    T;

Then it seems to take the path of RawDocType[]

I am a bit lost on why there all these branch conditions on the type.