code: function _entry(dirs) {
    return Utils.reduce(dirs, (memo, dir) => {
      const packs = glob.sync(resolve(dir, '**/*.pack.+(s[ac]ss|js)'));
      packs.forEach((pack) => {
        const key = relative(dir, pack).replace(/\.pack\.[^/.]+$/, '');
        /* eslint-disable-next-line no-param-reassign */
        memo[key] = [pack];
      });
  
      return memo;
    }, {});
  }
docs: Generates entry object by scanning directories
  for *.pack.scss, *.pack.sass, and *.pack.js files
  
  @param {array} dirs
  @return {Object} entry object