code: function bothForAndIFAttr(attrs) {
      if (!attrs) {
          return false;
      }
  
      let hasForAttr = FOR_DIRECTIVES.some(item => attrs[item]);
      let hasIf = CONDITION_DIRECTIVES.some(item => attrs[item]);
  
      return hasForAttr && hasIf;
  }
docs: for if 并存判断
  
  @param  {Object} attrs attrs
  @return {boolean}