code: function transformOfToIn(newValue) {
      const wordArray = newValue.trim().split(' ');
      const index = wordArray.indexOf('of');
      if (index !== -1 && !wordArray.includes('in')) {
          wordArray[index] = 'in';
          newValue = wordArray.join(' ');
      }
      return newValue;
  }
docs: transform 'of' to 'in'， 以支持for="item of items"语法
  
  @param {string} newValue 待转化的字符串
  @return {string} 被转化后的数组字符串