json格式转树状结构

转自：http://rockyuse.iteye.com/blog/1541308

/**
* json格式转树状结构
* @param {json} json数据
* @param {String} id的字符串
* @param {String} 父id的字符串
* @param {String} children的字符串
* @return {Array} 数组
*/
function transData(a, idStr, pidStr, chindrenStr){
var r = [], hash = {}, id = idStr, pid = pidStr, children = chindrenStr, i = 0, j = 0, len = a.length;
for(; i < len; i++){
hash[a[i][id]] = a[i];
}
for(; j < len; j++){
var aVal = a[j], hashVP = hash[aVal[pid]];
if(hashVP){
!hashVP[children] && (hashVP[children] = []);
hashVP[children].push(aVal);
}else{
r.push(aVal);
}
}
return r;
}

var jsonData = eval('[
{"id":"4","pid":"1","name":"大家电"},
{"id":"5","pid":"1","name":"生活电器"},
{"id":"1","pid":"0","name":"家用电器"},
{"id":"2","pid":"0","name":"服饰"},
{"id":"3","pid":"0","name":"化妆"},
{"id":"7","pid":"4","name":"空调"},
{"id":"8","pid":"4","name":"冰箱"},
{"id":"9","pid":"4","name":"洗衣机"},
{"id":"10","pid":"4","name":"热水器"},
{"id":"11","pid":"3","name":"面部护理"},
{"id":"12","pid":"3","name":"口腔护理"},
{"id":"13","pid":"2","name":"男装"},
{"id":"14","pid":"2","name":"女装"},
{"id":"15","pid":"7","name":"海尔空调"},
{"id":"16","pid":"7","name":"美的空调"},
{"id":"19","pid":"5","name":"加湿器"},
{"id":"20","pid":"5","name":"电熨斗"}
]');

var jsonDataTree = transData(jsonData, 'id', 'pid', 'chindren');
console.log(jsonDataTree);
//结果如下：
[
{"id":"1","pid":"0","name":"家用电器", "chindren":[
{"id":"4","pid":"1","name":"大家电", "chindren":[
{"id":"7","pid":"4","name":"空调", "chindren":[
{"id":"15","pid":"7","name":"海尔空调"},
{"id":"16","pid":"7","name":"美的空调"}
]},
{"id":"8","pid":"4","name":"冰箱"},
{"id":"9","pid":"4","name":"洗衣机"},
{"id":"10","pid":"4","name":"热水器"}
]},
{"id":"5","pid":"1","name":"生活电器","chindren":[
{"id":"19","pid":"5","name":"加湿器"},
{"id":"20","pid":"5","name":"电熨斗"}
]}
]},
{"id":"2","pid":"0","name":"服饰","chindren":[
{"id":"13","pid":"2","name":"男装"},
{"id":"14","pid":"2","name":"女装"}
]},
{"id":"3","pid":"0","name":"化妆","chindren":[
{"id":"11","pid":"3","name":"面部护理"},
{"id":"12","pid":"3","name":"口腔护理"}
]}
]