Using toJSON() and _id with Mongoose

[carrickkv2]

With the old versions of mongoose, we could do something like this

interface IUser extends Document {
  name: string;
  email: string;
  avatar?: string;
}

On the documentation page, this is discouraged as it hurts performance.
So I followed the new advice by doing something like this.

export interface UserInterface {
  email: string;
  name: string;
  password: string;
  createdAt?: Date;
  updatedAt?: Date;
  comparePassword(candidatePassword: string): Promise<boolean>; // Not a field but a function. This is why it should be omitted.
}

// Create a schema
const userSchema = new Schema<UserInterface>(
  {
    email: { type: String, required: true, unique: true },
    name: { type: String, required: true },
    password: { type: String, required: true },
  },
  {
    timestamps: true, // Set the date field for a schema.
  }
);

Unfortunately, if I try to access the default _id field and the toJSON() method, the ts compiler gives me an error.
Property 'toJSON' does not exist on type 'UserInterface'.ts(2339)
Property '_id' does not exist on type

For clarification, this is one of the functions I use toJSON() in.

export async function createUserHandler(
  req: Request,
  res: Response
): Promise<Response> {
  try {
    const user = await createUser(req.body);
    return res.json(omit(user.toJSON(), "password"));
  } catch (error: unknown) {
    const errorMessage = getErrorMessage(error);
    log.error(errorMessage);
    return res.status(409).json({ message: errorMessage });
  }
}

Since I can't extend the default document, I'm here to ask what I can do to access these fields and methods. I have read the documentation and looked at the code examples but so far I've seen nothing which can help me. Thanks

[vkarpov15]

The below script compiles with Mongoose 6.8.2, try this out:

import mongoose from 'mongoose';

export interface UserInterface {
  email: string;
  name: string;
  password: string;
  createdAt?: Date;
  updatedAt?: Date;
}

export interface UserMethods {
  comparePassword(candidatePassword: string): Promise<boolean>;
}

// Create a schema
const userSchema = new mongoose.Schema<UserInterface>(
  {
    email: { type: String, required: true, unique: true },
    name: { type: String, required: true },
    password: { type: String, required: true },
  },
  {
    timestamps: true, // Set the date field for a schema.
  }
);

type UserModel = mongoose.Model<UserInterface, {}, UserMethods>;
const UserModel = mongoose.model<UserInterface, UserModel>('User', userSchema);

const user = new UserModel({ email: 'test', name: 'test', password: 'test' });

const id: mongoose.Types.ObjectId = user.toJSON()._id;