json轉樹狀結構（js）

/** 
 * json格式轉樹狀結構 
 * @param    {json}      json數據 
 * @param    {String}    id的字符串 
 * @param    {String}    父id的字符串 
 * @param    {String}    children的字符串 
 * @return   {Array}     數組 
 */  
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":"你們電"},
{"id":"5","pid":"1","name":"生活電器"},
{"id":"1","pid":"0","name":"家用電器"},
{"id":"2","pid":"0","name":"服飾"},
{"id":"3","pid":"0","name":"化妝"},
{"id":"7","pid":"4","name":"空調"},
{"id":"8","pid":"4","name":"冰箱"},
{"id":"9","pid":"4","name":"洗衣機"},
{"id":"10","pid":"4","name":"熱水器"},
{"id":"11","pid":"3","name":"面部護理"},
{"id":"12","pid":"3","name":"口腔護理"},
{"id":"13","pid":"2","name":"男裝"},
{"id":"14","pid":"2","name":"女裝"},
{"id":"15","pid":"7","name":"海爾空調"},
{"id":"16","pid":"7","name":"美的空調"},
{"id":"19","pid":"5","name":"加溼器"},
{"id":"20","pid":"5","name":"電熨斗"}
]');  
  
var jsonDataTree = transData(jsonData, 'id', 'pid', 'chindren');  
console.log(jsonDataTree);  
//結果以下：
[
{"id":"1","pid":"0","name":"家用電器", "chindren":[
{"id":"4","pid":"1","name":"你們電", "chindren":[
{"id":"7","pid":"4","name":"空調", "chindren":[
{"id":"15","pid":"7","name":"海爾空調"},
{"id":"16","pid":"7","name":"美的空調"}
]},
{"id":"8","pid":"4","name":"冰箱"},
{"id":"9","pid":"4","name":"洗衣機"},
{"id":"10","pid":"4","name":"熱水器"}
]},
{"id":"5","pid":"1","name":"生活電器","chindren":[
{"id":"19","pid":"5","name":"加溼器"},
{"id":"20","pid":"5","name":"電熨斗"}
]}
]},
{"id":"2","pid":"0","name":"服飾","chindren":[
{"id":"13","pid":"2","name":"男裝"},
{"id":"14","pid":"2","name":"女裝"}
]},
{"id":"3","pid":"0","name":"化妝","chindren":[
{"id":"11","pid":"3","name":"面部護理"},
{"id":"12","pid":"3","name":"口腔護理"}
]}
]