处理list

Question

怎么把level为2的数据更简便的归类到level为1且 category === parent_category下？
level为1的数据下有children:[] 字段，
感谢

Answer 1

var arr=[
    {cate:'help',level:'1',par:''},
    {cate:'about',level:'1',par:''},
    {cate:'disc',level:'1',par:''},
    {cate:'dis_ins',level:'2',par:'disc'},
    {cate:'beian',level:'2',par:'disc'},
    {cate:'test',level:'2',par:'help'},
    {cate:'test_123',level:'2',par:'about'}
]

repl(arr);
function repl(arr){
  var cach = [],newArr=[];
  for(var i=0;i<arr.length;i++){
    var cate = arr[i].cate,
        par = arr[i].par;
    if(arr[i].level=='1'){
      arr[i].children=[];
      newArr.push(arr[i]);
      cach.push(cate);
    }else{
      var idx=cach.indexOf(par);
      if(idx!=-1){
        newArr[idx].children.push(arr[i]);
      }
    }
  }

Answer 2

如果只有两级的话,用下面这个

const result = arr
  .filter((a) => a.level === '1')
  .map(a => ({
    ...a,
    children: arr
      .filter(_a => _a.level === '2' && _a.parent_category === a.parent)
  }))

如果有多级的话,用递归

function classify(arr, level = '1', parent_category = '') {
  const children = arr.filter(
    a => a.level === `${level}` && a.parent_category === parent_category,
  )
  return children.length === 0
    ? children
    : children.map(a => ({
        ...a,
        children: classify(arr, parseInt(a.level, 10) + 1, a.parent),
      }))
}
const result = classify(arr)