javascript手写树形结构

const arr1 = [
  {
    menuId: 1,
    name: "系统管理1",
    parentMenu: null,
  },
  {
    menuId: 2,
    name: "系统管理2",
    parentMenu: null,
  },
  {
    menuId: 3,
    name: "系统管理1_0",
    parentMenu: 1,
  },
  {
    menuId: 4,
    name: "系统管理1_1",
    parentMenu: 1,
  },
  {
    menuId: 5,
    name: "系统管理2_0",
    parentMenu: 2,
  },
  {
    menuId: 6,
    name: "系统管理2_2_0",
    parentMenu: 5,
  },
  {
    menuId: 7,
    name: "系统管理3",
    parentMenu: null,
  },
  {
    menuId: 8,
    name: "系统管理1-1-2",
    parentMenu: 4,
  },
];
const arr2 = [
  {
    id: 1,
    name: "1",
    parentId: null,
  },
  {
    id: 2,
    name: "2",
    parentId: null,
  },
  {
    id: 3,
    name: "1_0",
    parentId: 1,
  },
  
];

function toTree2(arr, Id='id', parentId='parentId', children='children') {
  // 先copy一份数据
  let newA=JSON.parse(JSON.stringify(arr));
  return newA.filter(p=>{
    //遍历
    const c = newA.filter(item=>item[parentId]==p[Id]);
    //找到就赋值
    c.length && (p[children] = c)
    return p[parentId]==null
  })

}

const resultArr = toTree2(arr1,'menuId','parentMenu','list');
const resultArr1 = toTree2(arr2);
arr1[6].name='hedan';
console.log('树形结构', resultArr1);