vendors/tempy.js/groupPatternsByBaseDirectory
    function groupPatternsByBaseDirectory(patterns) {
      const group = {};
      return patterns.reduce((collection, pattern) => {
        const base = utils.pattern.getBaseDirectory(pattern);
        if (base in collection) {
          collection[base].push(pattern);
        } else {
          collection[base] = [pattern];
        }
        return collection;
      }, group);
    }