策略模式

/* 策略模式
一个问题匹配多个解决方案，不一定要用到哪一个，且有可能随时都会继续增加多个方案
实例：购物车
*/

const calcuPrice = (function () {
  const sale = {
    "100-10": function (price) {
      return (price -= 10);
    },
    "200-25": function (price) {
      return (price -= 25);
    },
    70: function (price) {
      return (price *= 0.7);
    },
  };
  function calcuPrice(price, type) {
    if (sale[type]) {
      return sale[type];
    }
  }
  //添加折扣
  calcuPrice.addDiscount = function (type, fn) {
    if (!sale[type]) {
      sale[type] = fn;
      return '添加成功'
    }
  };
  //删除折扣
  calcuPrice.deleDisCount = function (type) {
    if (sale[type]) {
      delete sale[type];
      return '删除成功'
    }
    return '无'
  };
  return calcuPrice;
})();
const res = calcuPrice(300, "70");
 const res1 = calcuPrice.addDiscount(400, function (price) {
  return price * 0.6;
});
console.dir(res1);
const resdel=calcuPrice.deleDisCount(400)
console.dir(resdel);