undefined jwt token react/express - express

Question

I am implementing a JWT authentication on a login/registration system. When there is a successful login/registration I am setting a user token in localStorage.
Problem is when I check my localStorage the user key is present but the value is undefined. I think the issue might be in my axios post or in my express file but I can't quite figure it out.
// my action creator
export function login(user, history) {
return async (dispatch) => {
axios.post('/api/login', { user })
.then(res => {
dispatch({ type: AUTHENTICATED });
localStorage.setItem('user', res.data.token);
history.push('/');
})
.catch((error) => {
dispatch({
type: AUTHENTICATION_ERROR,
payload: 'Invalid email or password'
});
});
};
}
The data is reaching my api correctly. The item is being set but the value res.data.token is undefined.. Below is my express file
// login.js (/api/login)
router.post('/', function(req, res) {
var email = req.body.user.email;
var password = req.body.user.password;
// TODO: create db file and import connection
var connection = mysql.createConnection({
host: "localhost",
user: "root",
password: "",
database: "dbname",
port: 3307
});
connection.connect(function(err) {
if(err) {
console.log(err);
} else {
connection.query("SELECT ID, Password FROM Users WHERE Email = ?", [email], function(err, result) {
if(err) {
console.log('Could not find account');
res.send(err);
} else {
var id = result[0].ID;
bcrypt.compare(password, result[0].Password, function(err, result) {
if(result) {
console.log(id);
res.json({ id });
} else {
console.log('Incorrect password');
}
});
}
});
}
});
});
Since the res.data.token in my action creator is returning undefined does that mean the response in my express file ( res.json([id]) ) is just returning defined?

Answer 1

You are not sending the response properly.
res.json([id]); Its just sending the array of id. That's why res.data.token is undefined. as data does not contain an object.
Send proper object like:
res.json({id});