JavaScript 객체 안에 함수 넣기.

const cat = {
  name: "집사",
  sound: "냥!",
  say: function() {
    console.log(this.sound);
  }
};

const dog = {
  name: "멍멍이",
  sound: "멍?",
  say() {
    console.log(this.sound);
  }
};

cat.say();
dog.say();