Cannot read properties of undefined (reading 'username')

May 10, 2023

hello i got this problem . And i still not find out my issue. thanks you for helping me
this is code of login.js

    var express = require('express');
var router = express.Router();
var db=require('../database');
/* GET users listing. */
router.get('/login', function(req, res, next) {
  res.render('login');
});

router.post('/login', function(req, res){
    var username = req.body.username;
    var password = req.body.password;

    var sql='SELECT * FROM users WHERE username =? AND password =?';
    db.query(sql, [username, password], function (err, data, fields) {
        if(err) throw err
        if(data.length>0){
            req.session.loggedinUser= true;
            req.session.username= username;
            res.redirect('/dashboard');
        }else{
            res.render('login',{alertMsg:"Your username or password is wrong"});
        }
    })

})

module.exports = router;

and this is my login page (

<!DOCTYPE html>
<html>
<head>  
</head>
<body>
<div class="login-form">
  <h3>Login Form</h3>
<p><%=(typeof alertMsg!='undefined')? alertMsg:''%></p>
<form method="post" action="/login">
      <input type="text" placeholder="Username" name="username" required">
      <input type="password" placeholder="Password" name="password" required">
       <button type="submit">Login Now</button>
       <a href="/register">New Registration</a>
  </div>
</form>
</div>

</body>
</html>

and when i enter username and password and click login button it get this error :

TypeError: Cannot read properties of undefined (reading ‘username’)

Image of the error . Click here

Im happy if you can help me

>Solution :

It seems that the issue is with accessing the ‘username’ property of the ‘req.body’ object, which is resulting in a TypeError.

You can try adding a middleware function to your ‘login.js’ file that parses the request body. You can do this by adding the following line at the top of your ‘login.js’ file:

router.use(express.urlencoded({ extended: true }));

This will enable you to access the ‘username’ and ‘password’ properties from the request body. Make sure to restart your server after making this change.

Hope this helps 🙂