[6.x] Why does Model's find methods returns Documet & { _id: any }

[imduchy]

I've noticed that after upgrading to 6.0.7, Model's find methods specify different return types. In 5.x, UserModel.findOne would return IUserDocument but now it returns IUserDocument & { _id: any }. I've noticed some changes in the TypeScript` part of the docs. Does that make my schema & types definitions obsolete?

export interface IUser {
  username: string;
  email: string;
  password: string;
  bets: Array<IBet>;
  groupId: Types.ObjectId;
}

// Looking into mongoose's type definitions, passing Types.ObjectId to Document should specify 
// type of _id. Doesn't seem to work with my current schema def.
export interface IUserDocument extends IUser, Document<Types.ObjectId> {
  _version: number;
  bets: Types.Array<IBetDocument>; // IBetDocument = IBet & Types.SubDocument
}

export type IUserModel = Model<IUserDocument>;

export const UserSchema = new Schema<IUserDocument, IUserModel>(
  {
    _version: { type: Number, required: true, default: 1 },
    username: { type: String, required: true, unique: true },
    email: { type: String, required: true, unique: true },
    password: { type: String, required: true },
    bets: [{ type: BetSchema, default: [], required: true }],
    groupId: { type: Schema.Types.ObjectId, ref: 'group' }
  },
  { timestamps: true }
);

[imduchy]

I refactored all my models into something like this.

export interface IUser {
  _version: number;
  username: string;
  email: string;
  password: string;
  bets: Array<IBet>; // Instead of IBetDocument = IBet & Types.Subdocument
  groupId: Types.ObjectId;
}

export type IUserModel = Model<IUser>;

export const UserSchema = new Schema<IUser, IUserModel>(
  {
    _version: { type: Number, required: true, default: 1 },
    username: { type: String, required: true, unique: true },
    email: { type: String, required: true, unique: true },
    password: { type: String, required: true },
    bets: [{ type: BetSchema, default: [], required: true }],
    groupId: { type: Schema.Types.ObjectId, ref: 'group' }
  },
  { timestamps: true }
);

Now, find queries return

const user = await User.findOne({ filter });
// user: (Document<any, any, IGroup> & IGroup & { _id: Types.ObjectId; }) | null

Seems more like it, right? But I can also see that user.bets is of type IBet[] instead of mongoose.Types.Array<IBet>. I'm not sure if that's correct.

[vkarpov15]

@Duchynko your models are correct. Does the fact that user.bets is of type IBet[] cause you any issues?

[imduchy]

@vkarpov15 models in the initial post/question or in the above comment?

That way I don't have access to $push and other methods of mongoose.Types.Array. I don't know if that causes any issues and if they can be used interchangeably with JS array's methods.

[vkarpov15]

They can be used interchangeably with JS array methods. Your models in #10833 (comment) look correct.