创建数据

const list = [];
for (let i = 0; i < 1000; i += 200) {
  if (i === 0) {
    list.push({ id: i - 1, age: '年龄-' + (i - 1) });
    list.push({ id: i, age: '年龄-' + i, parentId: -1 });
  } else {
    for (let index = i - 199; index <= i; index++) {
      list.push({ id: index, age: '年龄-' + index, parentId: i - 200 });
    }
  }
}

数据如图：

转换为children树结构

function treeData(source, id, parentId, children){   
    let cloneData = JSON.parse(JSON.stringify(source));
    return cloneData.filter(father=>{
        let branchArr = cloneData.filter(child => father[id] == child[parentId]);
        branchArr.length>0 ? father[children] = branchArr : '';
        return father[parentId] == -1; //返回第一层 我这里是-1 实际应用根据自己项目情况修改
    })
}
const data = treeData(list,'id','parentId','children')

转换后data如图，