列表转树

let arr = [
  {id: 1, name: '部门1', pid: 0},
  {id: 2, name: '部门2', pid: 1},
  {id: 22, name: '部门22', pid: 1},
  {id: 222, name: '部门222', pid: 1},
  {id: 3, name: '部门3', pid: 1},
  {id: 4, name: '部门4', pid: 3},
  {id: 5, name: '部门5', pid: 4},
]


const func = (list,pid) => list.filter(item=>item.pid == pid).map((item)=>({
  ...item,
  children:func(list,item.id)
}))

func(arr,0)
完美一句解决，
主要原理就是通过filter筛选出当层级的数据，然后通过递归反复调用

树转列表

const func1 = (treeList,accpet) => {
  treeList.map(item=>func1(accpet[accpet.push(item)-1].children||[],accpet))
  return accpet;
}
func1(JSON.parse(JSON.stringify(func(arr,0))),[])
这个看的有点迷糊，主要是用了js push后会返回数组长度。看不懂的话看下面的

const func1 = (treeList,accpet) => {
  treeList.map(item=>{
    accpet.push(item)
    func1(item.children||[],accpet)
  })
  return accpet;
}
func1(JSON.parse(JSON.stringify(func(arr,0))),[])