code: function compilePug(file, options) {
      let content = file.content.toString();
      // 取出用于pug模板的配置项，包括渲染所需的数据（data字段）
      let config = options.config || {};
      // 考虑到给之后的处理器传递数据，所以这里强制 pretty 为true
      config.pretty = true;
      let data = config.data;
      delete config.data;
  
      let fn = pug.compile(content, config);
      content = fn(data);
  
      return {
          content
      };
  }
docs: Compile pug template
  
  @param {Object} file the file to compile
  @param {Object} options for compile pug template
  @return {Object}