javascript - Please help with the problem of implementing shopping cart array! ! ! ! ! !

Each product has an id, title, and price. Every time I click to buy, I add it to the array. However, I want to judge based on the Id. When adding a product to the shopping cart repeatedly, add the same product to an array. How to write a dimensional array?

<code>[
    [
        {鸡腿},{鸡腿},{鸡腿},{鸡腿}
    ],
    [
        {狗腿},{狗腿},{狗腿}
    ],
    [
        {猫咪},{猫咪},{猫咪},{猫咪},{猫咪},{猫咪}
    ]
]




</code>

Thank you everyone, it’s true that my idea is really stupid, thank you for your suggestions!

Reply content:

Each product has an id, title, and price. Every time I click to buy, I add it to the array. However, I want to judge based on the Id. When adding a product to the shopping cart repeatedly, add the same product to an array. How to write a dimensional array?

<code>[
    [
        {鸡腿},{鸡腿},{鸡腿},{鸡腿}
    ],
    [
        {狗腿},{狗腿},{狗腿}
    ],
    [
        {猫咪},{猫咪},{猫咪},{猫咪},{猫咪},{猫咪}
    ]
]




</code>

Thank you everyone, it’s true that my idea is really stupid, thank you for your suggestions!

The friend above is right, your idea is not advisable. Two-dimensional arrays are all the same thing. . A bit of a trap.
This format is better, please refer to it

<code>var cart = {
    'id01':{n:'鸡腿', count: 4}，
    'id02':{n:'鸭腿', count: 3},
    'id03':{n:'猪腿', count: 2},
    'id04':{n:'狗腿子', count: 1}
}
</code>

However, if you insist on doing it this way

<code>var list = [
    [{n:'鸡腿'},{n:'鸡腿'},{n:'鸡腿'},{n:'鸡腿'},{n:'鸡腿'}],
    [{n:'鸭腿'},{n:'鸭腿'},{n:'鸭腿'},{n:'鸭腿'}],
    [{n:'猪腿'},{n:'猪腿'},{n:'猪腿'},{n:'猪腿'}]
];

function fn(o){
    var inArray = false;
    list.map(function(item){
        if( item.indexOf(o) > -1){
            inArray = true;
            item.push(o);
        }
    });
    inArray || list.push([o]);
}

fn(list[1][1]);

fn({n:'狗腿子'});
</code>

This is just a reference and is not recommended

It is not recommended to write like this. The data structure of the shopping cart should store the product ID and quantity (assuming that the product ID here is the name)

<code>{
    "鸡腿": 4,
    "狗腿": 3,
    "猫咪": 6
}
</code>

In actual implementation, when adding or subtracting items in the shopping cart, you only need to add or subtract the following number

Your thinking is wrong. What you said above is correct. The main body of the shopping cart should be $a = ['id'=>number], then the price and name should be another array $b = ['id'=>['name'=>name,'price'=>price]], and the total price is $totalPrice = $a['id']*$b['id']['price']

I agree with the point above that the items in the shopping cart should be as a whole, but I personally feel that the price should not be stored in the shopping cart array, because the price when you add it and the price when you pay are not necessarily the same. What should be stored is the unique identifier id and quantity number. If you store title, price, if the merchant changes the name or price, how should your design be handled?

<code>$shoppingCart = [
    '101' => 4,//鸡腿
    '102' => 5,//狗腿
    '103' => 6//鸭腿
];</code>

First of all, thank you for the invitation.

Actually, I saw this question yesterday, and I think the answers above were pretty good. But seeing that the author of the question invited me again, I can only express my opinion as a way to attract others.

---

Actually, I think the number of dimensions of the array is not important. It is not important how to write it. What is important is the idea. I mainly want to make an introductory statement on this aspect.
In fact, in this day and age, although object-oriented is a commonplace thing, many people still don’t know how to use it, so the complexity of the problem has skyrocketed. Let’s try to use object-oriented to solve this problem:

<code class="javascript">//全局对象
var item_arr = {};

//操作函数
function add_(id, name, price, count) {
    var item = {
        id: id,
        name: name,
        price: price,
        count: count
    }
    var obj = item_arr[id]
    if (obj) {
        item.count = obj.count + count;
    }
    item_arr[item.id] = item;
}
//code by rozbo ,强力免山寨


//模拟添加购物操作
add_(19, "狗腿子", 16, 20);
add_(1, "鸡腿子", 12, 2);
add_(126, "羊腿子", 6, 6);
add_(126, "羊腿子", 6, 6);


//输出信息，计算价格
var price_totle = 0;
for (var id in item_arr) {
    var item = item_arr[id];
    var price_curr = item.count * item.price;
    price_totle += price_curr;
    console.info("当前有%s%d个,总价%d元", item.name, item.count, price_curr);
}
console.info("共计%d元，祝您购物愉快！", price_totle);
</code>

Output results