code: function normalizeTagTransformInfo(nativeTag, transformItem) {
      if (typeof transformItem === 'string') {
          return {
              transformTag: transformItem,
              transformOpts: nativeTag
          };
      }
  
      let transformOpts = Object.assign({}, transformItem);
      transformOpts.tag = nativeTag;
  
      return {
          transformTag: transformItem.tag,
          transformOpts
      };
  }
docs: 将标签转换配置项转为 以 .tag 为 key 的值
  
  @param {string} nativeTag key
  @param {Object|string} transformItem tag or tag options
  @return {Object}