index.js

'use strict';

var isGlob = require('is-glob');
var pathPosixDirname = require('path').posix.dirname;
var isWin32 = require('os').platform() === 'win32';

var slash = '/';
var backslash = /\\/g;
var enclosure = /[\{\[].*[\/]*.*[\}\]]$/;
var globby = /(^|[^\\])([\{\[]|\([^\)]+$)/;
var escaped = /\\([\*\?\|\[\]\(\)\{\}])/g;

module.exports = function globParent(str) {
  // flip windows path separators
  if (isWin32 && str.indexOf(slash) < 0) {
    str = str.replace(backslash, slash);
  }

  // special case for strings ending in enclosure containing path separator
  if (enclosure.test(str)) {
    str += slash;
  }

  // preserves full path in case of trailing path separator
  str += 'a';

  // remove path parts that are globby
  do {
    str = pathPosixDirname(str);
  } while (isGlob(str) || globby.test(str));

  // remove escape chars and return result
  return str.replace(escaped, '$1');
};