这个文件在page 同名的js下面（https://opendocs.alipay.com/mini/framework/page-detail）

    1. ```java
    3. //变量定义
    4. var dish_all_cost = 0;
    5. var dish_all_menu = "";
    6. var current_bottom_menu_show = false;
    8. //
    9. Page({
    11.   //页面的数据
    12.   data: {
    13.     dish_count: 0,
    14.     dish_menu: "当前购物车是空的",
    15.     bottom_menu_show: false,
    17.     done_dishes: [
    18.       {
    19.         id: 1,
    20.         name: "可乐",
    22.       },
    23.       {
    24.         id: 2,
    25.         name: "薯条",
    27.       },
    29.     ]
    30.     ,
    32.   },
    35.   //这里定义的事件
    36.   handlebottomView(e) {
    37.     console.log("底部菜单被点击了");
    38.     if (!current_bottom_menu_show) {
    39.       this.setData({ bottom_menu_show: true });
    40.     } else {
    41.       this.setData({ bottom_menu_show: false });
    42.     }
    43.     current_bottom_menu_show = !current_bottom_menu_show;
    44.   },
    47.   handleDish(e) {
    48.   // 获取到当前事件
    49.     const dishInfo = e.target.dataset.dishInfo || {};
    50.     console.info("CLICK" + dishInfo.name);
    51.     dish_all_cost = dish_all_cost + dishInfo.price;
    52.     dish_all_menu = dish_all_menu + dishInfo.name + ";";
    53.     this.setData({ dish_menu: dish_all_menu });
    54.     this.setData({ dish_count: dish_all_cost });
    55.     var valueAble = false;
    56.     console.log("dishInfo"+dishInfo.id);
    60.         //https://www.cnblogs.com/m2maomao/p/7743143.html
    61.     //这里的循环为什么要of
    62.     //总结来说:for in总是得到对像的key或数组,字符串的下标,而for of和forEach一样,是直接得到值
    63.     for (var item of this.data.dishes) {
    64.       console.log("item"+item.id);
    65.       if( item.id == dishInfo.id){
    66.         valueAble = true;
    67.         break;
    68.       } else {
    69.         continue;
    70.       }
    71.     }
    72.     if(!valueAble){
    73.       console.log("当前点击不合法");
    74.       return;
    75.     } else {
    76.        console.log("当前点击合法");
    77.     }
    78.     for (var itemDone of this.data.done_dishes){
    79.       if(itemDone.id == dishInfo.id) {
    80.         var count = itemDone.amount;
    81.         var price = itemDone.price;
    82.         count = count + 1;
    83.         var totalCast = price * count;
    87.         //  这里相当于直接修改了值，
    91.         itemDone.amount = count;
    92.         itemDone.total_cost = totalCast;
    93.         // var SS= "itemDone.amount";
    94.         // this.setData({SS :count});
    95.         //  this.data.itemDone.amount = count;
    96.         console.log("this.setData.itemDone.amount"+itemDone.amount +"   "+count);
    98.       }
    99.     }
    101.     //更新当前的数组
    102.     this.setData({
    103.       'done_dishes':    this.data.done_dishes
    105.  });
    106.   },
    110. });

    ```