Excluding _id and including another prop in projection returns TS error

[DavideViolante]

Prerequisites

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

Mongoose version

8.15.0

Node.js version

22.x

MongoDB server version

idk

Typescript version (if applicable)

5.8.3

Description

I've the same bug reported also here by @msalafia
Note also my next comment there.
The bug is related to that PR changes.

In my project I have the error on this line:

const items = await User.find({}, { lastName: 1, _id: 0 });

Either if I remove lastName or _id it works, but is not the intended projection I want.

Error:

No overload matches this call.
  Overload 1 of 5, '(filter: RootFilterQuery<IUser>, projection?: ProjectionType<IUser>, options?: QueryOptions<IUser>): Query<...>', gave the following error.
    Type '0' is not assignable to type 'true | 1'.
  Overload 2 of 5, '(filter: RootFilterQuery<IUser>, projection?: ProjectionType<IUser>): Query<(Document<unknown, {}, IUser, {}> & IUser & Required<...> & { ...; })[], ... 4 more ..., {}>', gave the following error.
    Type '0' is not assignable to type 'true | 1'.ts(2769)

Steps to Reproduce

const items = await User.find({}, { lastName: 1, _id: 0 });

Schema:

import { Document, model, Schema, Types } from 'mongoose';

const userSchema = new Schema<IUser>({
  username: { type: String, trim: true },
  firstName: { type: String, required: true, trim: true },
  lastName: { type: String, required: true, trim: true },
  // ...
});

export interface IUser extends Document {
  _id: Types.ObjectId;
  username: string;
  firstName: string;
  lastName: string;
  // ...
}

const User = model<IUser>('User', userSchema);

export default User;

Expected Behavior

Ability to use _id: 0 and another prop.

[vkarpov15]

We're working on a fix, quick workaround is to do the following:

User.find({}, { lastName: 1, _id: 0 } as ProjectionType<any>);