docs: function isInRoot(root, filename) {
      root = path.normalize(root);
      filename = path.normalize(filename);
  
      if (root === '.') {
          return true;
      }
      if (root[root.length - 1] != path.sep) {
          root = root + path.sep;
      }
  
      return (filename.substr(0, root.length) === root);
  }