javascript - 连接嵌套对象数组的元素

Question

我有以下数组:

[
  {
    "OrderID": 1,
    "OrderDetails": [
      {
        "OrderDetailID": 7,
    "ProductCode": "E456",
        "Quantity": 1,
      },
      {
        "OrderDetailID": 8,
    "ProductCode": "E888",
        "Quantity": 2
      }
    ],
    "OrderDate": "8/1/2018"
  },
  {
    "OrderID": 2,
    "OrderDetails": [
      {
        "OrderDetailID": 9,
    "ProductCode": "N522",
        "Quantity": 3
      }
    ],
    "OrderDate": "10/1/2018"
  }
]

使用 JavaScript，我需要将所有 productCodes 连接成一个字符串，因此结果应如下所示:

E456;E888;N522

我已经尝试使用 map 函数来获取 OrderDetails 并且能够这样做。但是当我像下面这样再次链接 map 函数时，details 变量总是返回 undefined 所以我什至不能调用 join 函数来进行连接:

var details = this.orderData.map(function(i) {
     return {
         detail: i.OrderDetails
     }}).map(function(j) {
        return {
           x: j.detail.ProductCode
        }});

Answer 1

const arr=[{OrderID:1,OrderDetails:[{OrderDetailID:7,ProductCode:"E456",Quantity:1},{OrderDetailID:8,ProductCode:"E888",Quantity:2}],OrderDate:"8/1/2018"},{OrderID:2,OrderDetails:[{OrderDetailID:9,ProductCode:"N522",Quantity:3}],OrderDate:"10/1/2018"}];

const resp = arr.map(x => x.OrderDetails.map(y => y.ProductCode).join(';')).join(';');

console.log(resp)