Username undefined even though schema and model were already defined - node.js

Question

Please help review my error. I have defined my user schema but it is still undefined. I have spent hours on this error but I cannot seem to find where did I go wrong.
Here's my schema and model:
const { model, Schema } = require("mongoose");
const userSchema = new Schema({
username:String,
employeeId: String,
accessLevel: String,
role: String,
company: String,
password: String,
email: String,
createdAt: Date,
});
module.exports = model("User", userSchema);
Here's controller:
const User = require("../models/user");
const registerUser = (req, res, next) => {
let user = new User({
username: req.body.username,
employeeId: req.body.employeeId,
accessLevel: req.body.accessLevel,
role: req.body.role,
company: req.body.company,
password: req.body.password,
email: req.body.email,
createdAt: new Date(),
});
module.exports = {
registerUser
};
Here's connection to DB and server:
const express = require("express");
const mongoose = require("mongoose");
const { MONGODB } = require("./config");
const userRoute = require("./routes/userRouter");
const PORT = process.env.PORT || 4000;
mongoose
.connect(MONGODB, { useNewUrlParser: true, useUnifiedTopology: true })
.then(console.log("Database connected"))
.catch((err) => {
console.log(err);
});
const server = express();
server.use((err, req, res, next) => {
console.error(err);
res.status(err.statusCode).json(err);
});
server.use("/api/user", userRoute);
server.use(express.urlencoded({ extended: true }));
server.use(express.json());
server.listen(PORT, () => console.log(`Server is listening on ${PORT}`));
Here's router:
const express = require("express");
const usersControllers = require("../controllers/usersControllers");
const router = express.Router();
router.post("/registeruser", usersControllers.registerUser);
module.exports = router;
Post request on Postman: http://localhost:4000/api/user/registeruser
body:
{
"username": "Susan",
"employeeId": "12345",
"accessLevel": "Account Admin",
"role": "MC - Engineer",
"company": "Mello",
"password": "Choochootrain",
"email": "susan#hotmail.com"
}

Answer 1

Try to change the order of your middleware declarations:
const server = express();
server.use(express.urlencoded({ extended: true }));
server.use(express.json());
server.use("/api/user", userRoute);
server.use((err, req, res, next) => {
console.error(err);
res.status(err.statusCode).json(err);
});