code: function _mergeListInfo(list) {
              var arr = [];
              var info = {};
              for(var i=0,len=list.length; i<len; i++) {
                  arr.push('<li data-value="'+list[i].value+'">' + list[i].name + '</li>');
  
                  info[i] = list[i].list ? _mergeListInfo(list[i].list) : {length: 0};
              }
              info.length = i;
              info.content = arr.join('');
  
              return info;
          }
docs: merge options list