When I try to use an invaild email adress in the Login form, the app crashes saying: Cannot read properties of undefined (reading 'password').

You can see my auth.js's Login part below:

exports.login = async (req, res) => {
    try {
        const { email, password } = req.body;

        if ( !email || !password ) {
            return res.status(400).render('login', {
                message: 'Please provide an email and password.'
            })
        }

        db.query('SELECT * FROM users WHERE email = ?', [email], async (error, results) => {
            console.log(results);
            if( !results || !(await bcrypt.compare(password, results[0].password) ) ) {
                res.status(401).render('login', {
                    message: 'Email or password is incorrect.'
                })
            } else {
                const id = results[0].id;

                const token = jwt.sign({ id }, process.env.JWT_SECRET, {
                    expiresIn: process.env.JWT_EXPIRES_IN
                });

                console.log('The token is: '   token);

                const cookieOptions = {
                    expires: new Date(
                        Date.now()   process.env.JWT_COOKIE_EXPIRES * 24 * 60 * 60 * 1000
                    ),
                    httpOnly: true
                }

                res.cookie('jwt', token, cookieOptions);
                res.status(200).redirect("/");
            }
        })

    } catch (error) {
        console.log(error);
    }
}

It should show the same line that I can see when I use an incorrect password (That part works just fine).

message: 'Email or password is incorrect.'

CodePudding user response：

If the email is invalid, the query will return an empty array, not an undefined, meaning that your check is wrong - you should check the length of the array.

Of course, you can always leave the check that result is defined just to be on the safe side:

if( !results || !results.length || !(await bcrypt.compare(password, results[0].password) ) ) {
    res.status(401).render('login', {
        message: 'Email or password is incorrect.'
    });
} else {