hi
amazing project , helped me a lot and works easily
I got response 401 wrong email or password
it was because syntax mistake at line 30 of server.js

// Check if the user exists in database
function isAuthenticated({ email, password }) {
------>>>> // return userdb.users.findIndex(user => user.email === email && user.password === password) !== -1 <<<<-------
return userdb.users.findIndex(user => (user.email === email && user.password === password) !== -1)
}

just brackets