結構宣告

 📌 const cart = {
     list: {}
 }

list 裡面會所選的商品資料

商品宣告

 📌 init: function (ID, Name, Price, Amount,Max_Amount, overwrite = true)
 {
     if (overwrite) this.list[ID] = {"Name": Name, "Price": Price, "Amount":          Amount,"Max_Amount":Max_Amount};
 }

新增商品

如果這個商品

在清單不成出現過

新增在清單

如果有出現過

清單裡的商品數量改變

刪除商品

 📌 del: function (ID)
 {
     delete this.list[ID];
 }

刪除清單中的指定編號

總金額計算

 📌 total: () =>
 {
     let price = 0;
     Object.entries(shop.list).forEach(([key, value]) =>
     {
         price += (parseInt(value["Price"]) * parseInt(value["Amount"]));
     });
     return price;
 }

數量 * 價格 = 所選商品須付的總金額

完整程式碼

 📌 const shop = {
 list: {},
 add: function (ID, Name, Price, Amount,Max_Amount)
 {
     if (this.list.hasOwnProperty(ID))
     {
         this.list[ID]["Amount"] = parseInt(this.list[ID]["Amount"]) + parseInt(Amount);
     }
     else
     {
         shop.init(ID, Name, Price, Amount,Max_Amount);
     }
 },
 init: function (ID, Name, Price, Amount,Max_Amount, overwrite = true)
 {
     if (overwrite) this.list[ID] = {"Name": Name, "Price": Price, "Amount":     Amount,"Max_Amount":Max_Amount};
 },
 del: function (ID)
 {
     delete this.list[ID];
 },
 total: () =>
 {
     let price = 0;
     Object.entries(shop.list).forEach(([key, value]) =>
     {
     price += (parseInt(value["Price"]) * parseInt(value["Amount"]));
     });
     return price;
 }
 };

這樣一來就有間的的購物車功能了~