code: function transformFile(contents) {
          var $ = cheerio.load(contents.toString());
          var result = [];
          $(options.selector).each(function() {
              var element = $(this);
              var fileName = options.getFileName(element);
              result.push(fileName);
          });
  
          return result;
      }
docs: Returns an array of matched files - empty if no file is found.
  @param contents
  @returns {Array}