code: function handleFieldBelong (field, names, space, factory) {
  
              var curr = names.shift();
              if ( curr ) {
                  space.forEach(function (item) {
                      if ( item && item.field === curr ) {
                          if ( names.length === 0 ) {
                              if ( !item[field] ) {
                                  item[field] = [];
                              }
                              item[field].push(factory)
                          } else if ( item.param ) {
                              handleFieldBelong(field, names, item.param, factory);
                          }
                      }
                  });
              }
          }
docs: 创建其他字段层级化关系
  @param  {String} field 所属字段名
  @param  {Object} space 所属层级
  @param  {Object} factory 附属工厂