Setting up the user login

Now that we have successfully implemented the login process for a user, let's start building the functionality to log users in to our app.

Modifying the User model

To log in users to the app, we will take the following two parameters: the user's email and their password. We will need to query the database to find the record with their given email; so, let's add a method that will extract the user according to the username:

...
const User = mongoose.model('User', UserSchema);
module.exports = User;

module.exports.createUser = (newUser, callback) => {
  bcryptjs.genSalt(10, (err, salt) => {
    bcryptjs.hash(newUser.password, salt, (error, hash) => {
      // store the hashed password
      const newUserResource = newUser;
      newUserResource.password = hash;
      newUserResource.save(callback);
    });
  });
};

module.exports.getUserByEmail = (email, callback) => {
  const query = { email };
  User.findOne(query, callback);
};

The preceding method will...