将普通的数组转换为父子结构

//将普通的数组转换为父子结构
transformTozTreeFormat: function (sNodes) { 
    var i, l;
    var r = [];
    var tmpMap = {};
    for (i = 0, l = sNodes.length; i < l; i++) {
      tmpMap[sNodes[i].id] = sNodes[i];
    }
    for (i = 0, l = sNodes.length; i < l; i++) {
      var p = tmpMap[sNodes[i].pid];
      if (p && sNodes[i].id != sNodes[i].pid) {
        var children = this.nodeChildren(p);
        if (!children) {
          children = this.nodeChildren(p, []);
        }
        children.push(sNodes[i]);
      } else {
        r.push(sNodes[i]);
      }
    }
    return r;
  }