1、根据id查询当前对象
//list:遍历的对象，id:查询所需的id
function getObjById(list, id) {
if (!list instanceof Array) return null;
for(let i in list){
let item = list[i];
if(item.id === id) return item;
else {
if(item.children) {
let obj = getObjById(item.children, id);
if(obj) return obj
console.log(getObjById(cityList, '1-1-2')); //{ id: '1-1-2', name: '金牛区' }
2、根据id查询当前对象及所有父级节点对象
function getParentsById(list, id) {
for (let i in list) {
let item = list[i];
if (item.id === id) return [item];
if (item.children) {
let node = getParentsById(item.children, id)
if (node !== undefined) return node.concat(item)
console.log(getParentsById(cityList,'1-1-2'))
3、根据id查询当前对象及所有子级节点对象
function getChildren(list, returnValue = []) {
for (let i in list) {
let item = list[i];
returnValue.push(item)
if (item.children) {
getChildren(item.children, returnValue)
