function fn(data, pidvalue, options) {
var result = [], temp;
var {pid, id} = options;
for (var i = 0; i < data.length; i++) {
if (data[i][pid] == pidvalue) {
var obj = data[i];
temp = fn(data, data[i][id], options);
if (temp.length > 0) {
obj.children = temp;
}
result.push(obj);
}
}
return result;
}
pidvalue parentId的值,可以传null
options {pid, id} pid代表数据结构中的父级id字段,id代表当前item的id