Question

我正在尝试创建一个股票交易者应用程序，并且我有一个空数组来购买股票。每个购买的股票都会向数组添加一个对象。如果再次购买了相同的股票，我要检查库存，然后仅将数量附加到相关的数组。否则我只想追加新对象。

我已经尝试过使用for Each循环和一些函数，但是我似乎无法获取已经购买的当前元素并仅更新其数量。我能够获取要添加的数量，但无法添加到该对象。

item是要附加到数组的对象。仅当对象已经在数组中时才是数量；谢谢！

stocks = [
        {id:0, name:'BMW', price:5 , quantity:0},
        {id:1, name:'Google',price:20, quantity:0},
        {id:2, name:'IBM', price:34, quantity:0},
        {id:3, name:'Apple', price:15,quantity:0}
    ];
...
...
 stockPortfolio =[]
...
   //the item is the 
        'ADD_PORTFOLIO_ITEM'(stockPortfolio , item){
      //checking if an itemid  exists            
     // if not create  a new one            
            const arrayP = stockPortfolio            
            const found = arrayP.some(el => el.name === item.name);
            if (found) {

            }
            else{

Answer 1

const found = stockPortfolio.find(el => el.name === item.name);
if (found) {
    // found contains the matched item
} else {
    // no match found, add to array
}

Answer 2

这对我有用。如果您遇到任何问题，请告诉我。我正在更改stockPortfolio的原始数组。如果要返回新数组，请在函数'addStock'的开头使用.slice()

const stocks = [
        {id:0, name:'BMW', price:5 , quantity:0},
        {id:1, name:'Google',price:20, quantity:0},
        {id:2, name:'IBM', price:34, quantity:0},
        {id:3, name:'Apple', price:15,quantity:0}
    ];

let stockPortfolio = [ ];

function addStock(stockPortfolio , item) {
  let found = stockPortfolio .some(el => el.name === item.name)
  if (!found) {
     stockPortfolio.push(item);

  } else {
      for (var i = 0; i < stockPortfolio.length; i++) {
        if (stockPortfolio[i].name === item.name) {
          stockPortfolio[i].quantity += item.quantity;
        }
      };
  };
};

如何更新数组中特定对象的属性

2 个答案: