how to resolve data and hash error in node js bcrypt - node.js

Question

Error: data and hash arguments required
i am doing simple, login signup and forgot password in node js using
bcrypt hash
code : for login
app.post('/login', (req, res) => {
console.log('login');
let {email, password} = req.body;
User.updateOne({email: email}, ' email password', (err, userData) => {
if (!err) {
let passwordCheck = bcrypt.compareSync(password, userData.password);
if (passwordCheck) {
console.log('login2');
req.session.user = {
email: userData.email,
id: userData._id
};
req.session.user.expires = new Date(Date.now() + 3 * 24 * 3600 * 1000);
res.status(200).send('You are logged in, Welcome!');
} else {
res.status(401).send('incorrect password');
console.log('login3');
}
} else {
res.status(401).send('invalid login credentials');
console.log('login4');
}
});
});
code for signUp :
app.post('/signup', (req, res) => {
let {email, password} = req.body;
let userData = {password: bcrypt.hashSync(password, 5, null), email };
console.log('out save');
let newUser = new User(userData);
newUser.save().then(error => {
if (!error) {
console.log('in save');
return res.status(200).json('signup successful');
} else {
if (error.code === 11000) {
return res.status(409).send('user already exist!');
} else {
console.log(JSON.stringigy(error, null, 2));
return res.status(500).send('error signing up user');
}
}
});
});
i have tried console logging few lines and turned out that the code doesn't go into signup
newUser.save();
tell me where i'm going wrong

Answer 1

The issue is with this line newUser.save().then(error => {. Do you notice the .then(). That is a resolved promise so it wouldn't be returning an error. Typically you would see something like this.
Promise()
.then((result) => {
// result is a resolved promise
})
.catch((error) => {
// error is a rejected promise
})
So you should try changing your code to this:
newUser.save()
.then(result => {
console.log('in save')
return res.status(200).json('signup successful')
})
.catch(error => {
if (error.code === 11000) {
return res.status(409).send('user already exist!')
} else {
console.log(JSON.stringigy(error, null, 2))
return res.status(500).send('error signing up user')
}
})
It looks like you're using mongoose, here is the API docs for Document.prototype.save() https://mongoosejs.com/docs/api.html#document_Document-save
Their documentation uses callback functions for the most part but if you scroll to the end of the .save() documentation you will see they show one example with a promise.

Answer 2

bcrypt.compareSync takes 2 parameters; passwordToCheck, passwordHash
You are getting error "bcrypt Error: data and hash arguments required"
This error means one or both parameters are either null or undefined,
In your case you need to make sure that password, userData.password are correctly going in function bcrypt.compareSync