엘리 [자바스크립트 기초 강의] 콜백지옥 수정

    loginUser (id, password) {
        return new Promise((resolve, reject) => {
            setTimeout(() => {
                if (
                    (id === 'dongdu' && password === 'jjang')||
                    (id === 'umma' && password == 'jjangjjang')
                ) {
                    resolve(id);
                } else {
                    reject(new Error('not found'));
                }
            }, 2000);
        }); 
    }

    getRoles (user) {
        return new Promise((resolve, reject) => {
            setTimeout(() => {
                if (user === 'dongdu') {
                    resolve({name: 'dongju', role: 'admin'});
                } else {
                    reject(new Error('no access'));
                }
            }, 1000);
        })
    }
}

const userStorage = new UserStorage();
const id = prompt('enter your id.');
const password = prompt('enter your password.');
userStorage.loginUser(id, password)
    .then(userStorage.getRole)
    .then(user => alert(`Hello ${user.name}, you have a ${user.role} role.`))
    .catch(console.log)