javascript - 如何避免嵌套映射以从嵌套数组中获取我需要的值？

Question

我正在做这样的事情来获得我需要的值:

   tableRowsItems = data.softy.map(row =>
      row.items.map(item => console.log('item', item)),
    );

这样，我得到了如下图所示的东西，这正是我所需要的

我的问题是这是否是正确的 ES6 方法。如果有帮助，我也在使用 lodash。

这是没有 map 的 json 文件的样子:

[
 {
  "ticketId": 67973802,
  "account": null,
  "items": [
    {
      "id": 11705294,
      "billingItemId": 361643044,
      "cancellationRequestId": 17289674,
      "immediateCancellationFlag": true,
      "scheduledCancellationDate": null,
      "serviceReclaimStatusCode": "COMPLETE",
      "billingItem": {
        "description": "Storage as a Service",
        "recurringFee": 0,
        "id": 361643044
      }
    }
  ]
 },
 ...
]
... 

我需要的是你在 items 键上看到的内容

Answer 1

使用ES6，您可以轻松地通过Array.reduce 的items 属性执行一行函数来帮助您展平嵌套数组。 :

var tickets = [{ "ticketId": 67973802, "account": null, "items": [{ "id": 117052912, "billingItemId": 36164304123, }, { "id": 11705232, "billingItemId": 361643044, }] }, { "ticketId": 67973802, "account": null, "items": [{ "id": 117052945, "billingItemId": 361643046, }, { "id": 117052953, "billingItemId": 361643049, }] } ];
 
const pullBy = (arr, prop) => arr.reduce((r,c) => [...r[prop], ...c[prop]])
 
console.log(pullBy(tickets, 'items'))

使用 lodash 最好的选择是flatMap :

var tickets = [{ "ticketId": 67973802, "account": null, "items": [{ "id": 117052912, "billingItemId": 36164304123, }, { "id": 11705232, "billingItemId": 361643044, }] }, { "ticketId": 67973802, "account": null, "items": [{ "id": 117052945, "billingItemId": 361643046, }, { "id": 117052953, "billingItemId": 361643049, }] } ];
 
const result = _.flatMap(tickets, 'items')
 
console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>