Convert flat data to tree format 平铺格式转树状结构

flat-data-to-tree.js

/**
 * Convert flat data to tree format
 *
 * @see http://blog.csdn.net/chelen_jak/article/details/21290769
 *
 * @param   {array}  a    json数据
 * @param   {String} idStr   id的字符串
 * @param   {String} pidStr   父id的字符串
 * @param   {String} childrenStr   children的字符串
 * @return  {array}     数组
 */
function transData(a, idStr, pidStr, childrenStr){
  var r = [], hash = {}, children = childrenStr, i = 0, j = 0, len = a.length;
  for(; i < len; i++){
    hash[a[i][idStr]] = a[i];
  }
  for(; j < len; j++){
    var aVal = a[j], hashVP = hash[aVal[pidStr]];
    if(hashVP){
      !hashVP[children] && (hashVP[children] = []);
      hashVP[children].push(aVal);
    }else{
      r.push(aVal);
    }
  }
  return r;
}