code: function queryRefInstance(selector) {
      let isSelectAll = Array.isArray(selector);
      isSelectAll && (selector = selector[0]);
  
      let result;
      if (isSelectAll) {
          if (typeof this.selectAllComponents === 'function') {
              result = this.selectAllComponents(selector);
          }
          result || (result = []);
      }
      else if (typeof this.selectComponent === 'function') {
          result = this.selectComponent(selector);
      }
  
      return result;
  }
docs: Query the reference instance information by the given reference class
  
  @inner
  @param {string|Array.<string>} selector the reference class or id selector
  @return {?Object|Array}