实现存取器方法

const obj = {};

function add(o, name) {
  let value;

  obj["get" + name] = function () {
    return value;
  };
  obj["set" + name] = function (v) {
    value = v;
  };
}

// 存值
add(obj, "item");
obj.setitem(100000);
obj.getitem();

const obj = {
  val: 0,

  set myVal(age) {
    this.val = ++age;
  },

  get oct() {
    return this.val * 100;
  },
};

// 存
obj.myVal = 100;

// 取
console.log(obj.oct);

function counter() {
  let n = 0;

  return {
    count: function () {
      return n++;
    },

    reset: function () {
      n = 0;
    },
  };
}

const c = counter();
console.log(c.count()); //0
console.log(c.count()); //1