How to implement multi roles user authentication using express and mongoose? - node.js

Question

I'm trying to create a MERN app where there will be multiple roles like 'principle', 'teacher', 'student', 'guardian'. Primarily I have created userModel to register users and create a role key that will have the different role values pointing to other models (like teacherModel/ studentModel).
My userModel is like that
const mongoose = require('mongoose')
const userSchema = mongoose.Schema(
{
email: {
type: String,
required: [true, 'Please add an email'],
unique: true
},
password: {
type: String,
required: [true, 'Please add a password']
},
role: [
{
type: mongoose.Schema.ObjectId,
ref: 'Teacher'
},
{
type: mongoose.Schema.ObjectId,
ref: 'Student'
}
]
},
{
timestamps: true
}
)
module.exports = mongoose.model('User', userSchema)
and the teacherModel is
const mongoose = require('mongoose')
const teacherSchema = mongoose.Schema({
name: {
type: String,
required: [true, 'Please add your name']
},
teacherId: {
type: Number,
required: [true, 'Please add your teacher id']
}
})
module.exports = mongoose.model('Teacher', teacherSchema)
I have created an userConroller, I want to register a user with their name, email, password, and role. I have put the name into the individual role so that I can search teachers or students separately, not both. Here, is my userController
const asyncHandler = require('express-async-handler')
const bcrypt = require('bcryptjs')
const User = require('../models/userModel')
// #description Register a new user
// #route /api/users
// #access Public
const registerUser = asyncHandler(async (req, res) => {
const { email, password, role } = req.body
// Validation
if (!name || !email || !password || !role) {
res.status(400)
throw new Error('Please include all fields')
}
// Find if user already exists
const userExists = await User.findOne({ email })
if (userExists) {
res.status(400)
throw new Error('User already exists')
}
// Hash Password
const salt = await bcrypt.genSalt(10)
const hashedPassword = await bcrypt.hash(password, salt)
const user = await User.create({
email,
password: hashedPassword,
role,
})
if (user) {
res.status(201).json({
_id: user._id,
email: user.email,
role: user.role
})
} else {
res.status(400)
throw new error('Invalid user data')
}
})
When I try to register with postman, I get this error message,
"User validation failed: role.0: Cast to [ObjectId] failed for value
"[ 'teacher' ]" (type string) at path "role.0" because of
"CastError""
What have I messed up?