如何使用Js 将JSON数据转换为json树数据

Question

var nodes = [
{"id":2,"title":"第一级1","parentid":0},
{"id":3,"title":"第二级1","parentid":2},
{"id":4,"title":"第二级2","parentid":2},
{"id":5,"title":"第三级1","parentid":4},
{"id":6,"title":"第三级2","parentid":3}
];
var newnode;
var t={};
for(var i in nodes){t[nodes[i].id]=nodes[i];nodes[i].children=[]}
for(var i in nodes){if(nodes[i].parentid){var v=t[nodes[i].parentid].children;v[v.length]=nodes[i]}else newnode=nodes[i];delete nodes[i].parentid}
alert(JSON.stringify(newnode));