자바스크립트 getter, setter

getter함수

const numbers = {
  a: 1,
  b: 2,
  get sum(){
    console.log('sum함수가 실행됩니다!');
    return this.a + this.b;
  }
};

console.log(numbers.sum);
numbers.b = 5;
console.log(numbers.sum);

 

getter, setter 함수

 

const numbers = {
  _a: 1,
  _b: 2,
  sum: 3,
  calculate() {
    console.log("calculate");
    this.sum = this._a + this._b;
  },
  get a() {
    return this._a;
  },
  get b() {
    return this._b;
  },
  set a(value) {
    this._a = value;
    this.calculate();
  },
  set b(value) {
    this._b = value;
    this.calculate();
  }
};

console.log(numbers.sum);
numbers.a = 5;
numbers.b = 7;
numbers.a = 9;
console.log(numbers.sum);