How to use require and esm in 1 project?

Question

I use node version 16.14.2, and I try to use ES Module in my project. Below my package.json.

{
  "name": "community",
  "version": "0.0.1",
  "description": "community",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "start": "nodemon server.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "dotenv": "^16.0.0",
    "express": "^4.17.3",
    "express-async-handler": "^1.2.0",
    "jsonwebtoken": "^8.5.1",
    "mysql": "^2.18.1",
    "mysql2": "^2.3.3",
    "nodemon": "^2.0.15",
    "sequelize": "^6.19.0"
  },
  "devDependencies": {
    "sequelize-cli": "^6.4.1"
  }
}

I use Sequelize for ORM, and I use sequelize-cli to generate model. My model models/userModel.js

'use strict';
const {
  Model
} = require('sequelize');
module.exports = (sequelize, DataTypes) => {
  class User extends Model {
    static associate(models) {
    }
  }
  User.init({
    email: DataTypes.STRING,
    password: DataTypes.STRING,
  }, {
    sequelize,
    modelName: 'User',
  });
  return User;
};

and this is my controllers/userController.js

import User from '../models/userModel.js'
import asyncHandler from 'express-async-handler'
import generateToken from '../utils/generateToken.js'

const registerUser = asyncHandler(async(req, res) => {
  const { first_name, last_name, email, password } = req.body
  const userExists = await User.findOne({
    where: { email: email },
    order: [ [ 'createdAt', 'DESC' ]],
  });
  res.send('ok', userExists);
})

I have tried this :

a).I use import on my controller

import User from '../models/userModel.js'

But then I get an error

SyntaxError: The requested module '../models/userModel.js' does not provide an export named 'default'

b). So I change my Model to be like this one (use import and export default)

'use strict';
import { Model } from 'sequelize'
const userModel = (sequelize, DataTypes) => {
  class User extends Model {
    static associate(models) {
    }
  }
  User.init({
    email: DataTypes.STRING,
    password: DataTypes.STRING,
  }, {
    sequelize,
    modelName: 'User',
  });
  return User;
};
export default userModel;

I don't get any error on server, but when I try to fecth data (register user), I get error on my postman.

"message": "User.findOne is not a function",
"stack": "TypeError: User.findOne is not a function\n ....

Thank you.

Answer 1

How to use require and esm in 1 project?

Don't. It creates a mess. Use modern module syntax when not working in a legacy project.

I use Sequelize for ORM, and I use sequelize-cli to generate model.

The sequelize-auto command supports a -l esm parameter to generate ES6 ESM modules.