The 2nd parameter to `mongoose.model()` should be a schema, but it is a schema

Question

I'm trying to add user to my users collection in MongoDB. I'm using mongoose with NodeJS and Typescript, and when I try to run the project, I get the error:

The 2nd parameter to `mongoose.model()` should be a schema or a POJO
at Mongoose.model

The error states that the problem is in this file:

import { Router, Request, Response } from "express";
const UserType = require("../enums/UserType");
const UserSchema: mongoose.Schema = require("../schemas/UserSchema");
import mongoose from "mongoose";
import { v4 as uuidv4 } from "uuid";


export class UserRouter {
  router: Router;
  private userSchema = mongoose.model("UserSchema", UserSchema, "Users");

  constructor() {
    this.router = Router();
    this.init();
  }

  init() {
    this.router.post("/create", this.createUser);
  }

  //@ts-ignore
  async createUser(req: Request, res: Response) {
    const uid = uuidv4();
    const info = req.body;
    var user = new this.userSchema({
      uid: uid,
      username: info.username,
      password: info.password,
      type: UserType.User,
    });

    console.log(user);
  }
}

const userRouter = new UserRouter();
const router = userRouter.router;

export default router;

UserSchema is of type mongoose.Schema<any>, when hovering on it with the pointer, this is what pops up: const UserSchema: mongoose.Schema<any>

This is my UserSchema:

import mongoose from "mongoose";

const UserSchema = new mongoose.Schema({
  uid: {
    type: String,
    required: true,
    unique: true,
  },
  username: {
    type: String,
    required: true,
    unique: true,
  },
  password: {
    type: String,
    required: true,
  },
  type: {
    type: Number,
    required: true,
  },
  createdAt: {
    type: Date,
    default: Date.now,
  },
});

module.exports = mongoose.model("UserSchema", UserSchema);

Why do I keep getting this error message, even though it seems like the error should not be present?

Answer 1

The reason why you get this error is you declared the mongoose model in a recursive way: mongoose.model(UserSchema,mongoose.model(),"Users") in your code. You should export UserSchema instead of creating a schema model and exporting it. your code should look like this: module.exports.UserSchema = UserSchema; In the other module you could import the schema : const {UserSchema} = require("../schemas/UserSchema"); and eventually create a new model of the schema in the UserRouter class: private userSchema = mongoose.model("UserSchema", UserSchema);

It is possible to get the same error if you define mongoose.model() twice for the same schema:

Answer 2

import mongoose from 'mongoose';
const { Schema } = mongoose;

const blogSchema = new Schema

const UserSchema = new mongoose.Schema // delete new......