javascript - 如何在 JavaScript 中添加对象数组中的所有数量字段

Question

我试图显示购物篮中有多少商品，因此每个商品都有 qtyField: value，而不是显示购物篮的 arr.length。

就像在电子商务中一样，如果您的篮子里有 1 个苹果，篮子数量反射(reflect)了您拥有的商品数量。

var updateCartItem = {
        Products: [
      {  
           "product_idField":"96031",
           "skuField":"321005Y-00100-ITM",
           "nameField":"Cooper Sunglasses",
           "priceField":"75.0000",
           "qtyField":3,
           "qtyFieldSpecified":true,
           "$$hashKey":"object:8"
        },
          {  
           "product_idField":"another",
           "skuField":"another-ITM",
           "nameField":"Pony Sunglasses",
           "priceField":"75.0000",
           "qtyField":1,
           "qtyFieldSpecified":true,
           "$$hashKey":"object:8"
        },
        {  
           "product_idField":"empty",
           "skuField":"empty-ITM",
           "nameField":"Nobody wants it Sunglasses",
           "priceField":"75.0000",
           "qtyField":1,
           "qtyFieldSpecified":true,
           "$$hashKey":"object:8"
        }
     ]
    }
  
 updateCartItem.Products.forEach(function (element) {
                console.log(element.qtyField);
            }, this);

在上面的对象中，有 3 个项目，但 qtyField 的数量不同，因此我想添加所有 qtyField 值并显示总数。

Answer 1

您可以使用reduce :

var updateCartItem = {
        Products: [
      {  
           "product_idField":"96031",
           "skuField":"321005Y-00100-ITM",
           "nameField":"Cooper Sunglasses",
           "priceField":"75.0000",
           "qtyField":3,
           "qtyFieldSpecified":true,
           "$$hashKey":"object:8"
        },
          {  
           "product_idField":"another",
           "skuField":"another-ITM",
           "nameField":"Pony Sunglasses",
           "priceField":"75.0000",
           "qtyField":1,
           "qtyFieldSpecified":true,
           "$$hashKey":"object:8"
        },
        {  
           "product_idField":"empty",
           "skuField":"empty-ITM",
           "nameField":"Nobody wants it Sunglasses",
           "priceField":"75.0000",
           "qtyField":1,
           "qtyFieldSpecified":true,
           "$$hashKey":"object:8"
        }
     ]
    }
    
var total = updateCartItem.Products.reduce((acc,prod) => {
    return acc + prod.qtyField
}, 0);
console.log(total);