[JS]dot notation braket notation

dot notation

let user = {
  firstName: "Steve",
  lastName: "Lee",
};

user.firstName; // 'Steve'

braket notation

user["lastName"]; // 'Steve'

추가

user["city"] = "Seoul";

user.isAdult = true;

삭제

delete user.isAdult;

확인

"isAdult" in user; // false