'Cannot read properties of undefined (reading 'name')'

localhost:4000 can load Appointment.html properly but when i click on button submit it get routed to localhost:4000/add and shows errorCannot read properties of undefined (reading 'name')

app.js

const app = express();
const bodyParser = require('body-parser');
const router = require('./route/router');
app.use(router)

app.use(express.static(__dirname + '/public'));

app.use(bodyParser.json);
app.use(
  bodyParser.urlencoded({
    extended: false,
  }),
);

app.listen(4000);

router.js

const express = require('express');
const bodyParser = require('body-parser');
const controller = require('../controller/controller');

const router = express.Router();
router.get('/',controller.homePage);
router.get('/add',controller.getItem);
router.post('/add',(res,req)=>{console.log(res.body.name)})


module.exports = router;

controller.js

const { query } = require('express');
const Item = require('../models/item')


exports.getItem = (req, res, next) => {
    console.log('get!'+req)
}
exports.postItem = (req, res, next) => {
    console.log(req.body.name)
};

exports.homePage = (req, res, next) =>{
    res.sendFile(__dirname + '/Appointment.html');
}

In router.js try adding one line router.use(express.json());

As when you pass body from client if you are passing as an object it can’t de structure it. And while making request from client side also said frontend pass object as {name : “name”, ….}. Make sure the key name of the object is exactly same as you’re trying to de structure.