数组转对象,对象转数组,数组转树形结构

数组转对象

 const arr = [{ label: '男',value: 0}, {label: '女', value: 1 }]

  function f(arr) {
  //创建新对象
    let newarr = {}
    arr.forEach((k, index) => {
      // newarr.k = newarr[k]
      console.log(index);
      console.log(k);
      // 对象的属性=值
      newarr[index] = k.label
    });
    return newarr
  }
  const obj = f(arr) 
  console.log(obj);//  {0: '男', 1:'女'}

对象转数组

const obj = {  0: '男',  1: '女' }

  function f(obj) {
  
    let newarr = []
    for (let k in obj) {

      newarr.push({
        lable: obj[k],
        value: k
      })
    }
    return newarr

  }
  const arr = f(obj)
  console.log(arr);   // arr ===> [{label: '男', value: 0},{label: '女', value: 1}]

数组转树形结构

let data = [
  { id: '01', name: '张大大', pid: '', job: '项目经理' },
  { id: '02', name: '小亮', pid: '01', job: '产品leader' },
  { id: '03', name: '小美', pid: '01', job: 'UIleader' },
  { id: '04', name: '老马', pid: '01', job: '技术leader' },
  { id: '05', name: '老王', pid: '01', job: '测试leader' },
  { id: '06', name: '老李', pid: '01', job: '运维leader' },
  { id: '07', name: '小丽', pid: '02', job: '产品经理' },
  { id: '08', name: '大光', pid: '02', job: '产品经理' },
  { id: '09', name: '小高', pid: '03', job: 'UI设计师' },
  { id: '10', name: '小刘', pid: '04', job: '前端工程师' },
  { id: '11', name: '小华', pid: '04', job: '后端工程师' },
  { id: '12', name: '小李', pid: '04', job: '后端工程师' },
  { id: '13', name: '小赵', pid: '05', job: '测试工程师' },
  { id: '14', name: '小强', pid: '05', job: '测试工程师' },
  { id: '15', name: '小涛', pid: '06', job: '运维工程师' }
]



function toTree(data) {
  let result = []
  if (!Array.isArray(data)) {
    return result
  }
  let map = {}
  data.forEach(item => {
    map[item.id] = item
  })
  data.forEach(item => {
    let parent = map[item.pid]
    if (parent) {
      (parent.children || (parent.children = [])).push(item)
    } else {
      result.push(item)
    }
  })
  return result
}
console.log(toTree(data))

通过递归转tree

function arrToTree(list, pid=''){ 
 let children = []
 list.forEach(element => {
   if(element.pid===pid){
   先把一级数组添加到children里
     chi.push(element)
   然后立刻递归找他的儿子
     element.children=arrToTree(list,element.id)
     
   }     
   
 });
 return children
}
let tree =arrToTree(source)
console.log(data);   结果跟上边一样