vue.js数组中有多个子级，怎么把他们全部拼接到单个数组同一级中

Question

[
    {
      "id": 1,
      "title": "1",
      "children": [
        {
          "id": 2,
          "title": "1.1",
        },
        {
          "id": 3,
          "title": "1.2",
        },
        {
          "id": 4,
          "title": "1.3",
          "children": [],
        },
        {
          "id": 5,
          "title": "1.4",
					"children": [
            {
              "id": 6,
          		"title": "1.4.1",
              "children": [],
            },
              {
              "id": 7,
          		"title": "1.4.2",
            }
          ],
        },
        {
          "id": 8,
          "title": "1.5",
        }
      ]
    },
    {
      "id": 2,
      "title": "2",
      "children": [],
    }
  ],

Answer 1

 item.children.length > 0改为item.children && item.children.length > 0即可，仅判断item.children.length > 0可能会存在item.children不存在，导致item.children.length报错undifined。基本就是雨生百谷老铁的代码 

export function FlatArray (data) {
  console.log('原数组长度：', data.length)
  if (data.length === 0) {
    return []
  }
  let arr = []
  data.map((item) => {
    if (item.children && item.children.length > 0) {
      arr = arr.concat(FlatArray(item.children))
    } else {
      item.children = []
    }
    arr.push(item)
  })
  console.log('打平后数组长度：', arr.length)
  return arr
}