Correct way to deal with MySqlRawQueryResult

 db.insert(user).values({
            firstname: data.data.firstname,
            lastname: data.data.lastname,
            username: data.data.username,
            email: data.data.email,
            password: hash
        }).then((newUser) => {
           //How do i check if the user was created?
        }).catch((err) => {
            return res.status(500).json(err)
        })