1. <!DOCTYPE html>
    2. <html lang="en">
    3.     <head>
    4.         <meta charset="UTF-8" />
    5.         <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    6.         <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    7.         <title>策略模式</title>
    8.     </head>
    9.     <body>
    10.         <div class="eg2"></div>
    12.         <script>
    13.             const calcPrice = (() => {
    14.                 const sale = {
    15.                     "100_10": (price) => (price -= 10),
    16.                     "200_25": (price) => (price -= 25),
    17.                     "80%": (price) => (price *= 0.8),
    18.                 };
    20.                 function calcPrice(price, type) {
    21.                     if (!sale[type]) return "没有这个折扣";
    22.                     return sale[type](price);
    23.                 }
    25.                 calcPrice.add = (type, fn) => {
    26.                     if (sale[type]) return "该折扣已经存在";
    28.                     sale[type] = fn;
    29.                     return "添加成功";
    30.                 };
    32.                 calcPrice.del = (type) => {
    33.                     delete sale[type];
    34.                 };
    36.                 return calcPrice;
    37.             })();
    39.             calcPrice.add("70%", (price) => {
    40.                 return (price *= 0.7);
    41.             });
    42.             const res = calcPrice(320, "70%");
    43.             console.dir(res);
    45.             calcPrice.del("100_10");
    46.             const res2 = calcPrice(320, "100_10");
    47.             console.log(res2);
    48.         </script>
    49.     </body>
    50. </html>