arrays - typescript 将数组的特定属性连接为字符串

Question

我有一个 API，它给了我这样的响应:

{
  "item": [
    {
      "_id": "5a48e0c100a5863454c0af2a",
      "name": "Maths",
      "created_by": "5a43ee3231ad5a6b0850d961",
      "__v": 0,
      "created_on": "2017-12-31T13:06:09.957Z",
      "active": 1,
      "grade": [],
      "syllabus": [
        {
          "_id": "5a47a5faed12d92d0c2449f4",
          "name": "CBSE",
          "description": "CBSE Syllabus",
          "created_by": "5a43ee3231ad5a6b0850d961",
          "__v": 0,
          "created_on": "2017-12-30T14:43:06.305Z",
          "banner": 1,
          "active": 1
        },
        {
          "_id": "5a47a615ed12d92d0c2449f5",
          "name": "State Board",
          "description": "State Board Syllabus",
          "created_by": "5a43ee3231ad5a6b0850d961",
          "__v": 0,
          "created_on": "2017-12-30T14:43:33.328Z",
          "banner": 1,
          "active": 1
        }
      ]
    }
  ]
}

如您所见，在 maths 数组中有一个名为 item 的项目。现在在数学里面，我们有另一个 syllabus 数组。我想加入 maths 的所有教学大纲的名称。简单来说，说我想做这样的事情:

array element 1 - maths - CBSE, State Board
array element 2 - chemistry - CBSE, State Board

AFAIK，我们不能没有 2 forEach 循环。有没有更好的方法来处理这种情况？

Answer 1

大概是这样的:

  const result = item.map(it => ({
      name: it.name,
      syllabi: it.syllabus.map(s => s.name).join(', ')
    }));

https://jsfiddle.net/ernmtcgj/