code: function (files) {
    return files.reduce(function (filesMap, file) {
      let fileName = path.parse(file).name;
      filesMap[fileName] = readFile(file, 'utf8');
  
      return filesMap;
    }, {});
  }
docs: mapFiles() returns an object based on passed file path array
  mapping file name as key and promised content as value
  
  @param {Array} files
  @return {Object} filesMap