index.js

'use strict';

var isWindows = process.platform === 'win32';

// Regex to split a windows path into three parts: [*, device, slash,
// tail] windows-only
var splitDeviceRe =
    /^([a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/]+[^\\\/]+)?([\\\/])?([\s\S]*?)$/;

// Regex to split the tail part of the above into [*, dir, basename, ext]
var splitTailRe =
    /^([\s\S]*?)((?:\.{1,2}|[^\\\/]+?|)(\.[^.\/\\]*|))(?:[\\\/]*)$/;

var win32 = {};

// Function to split a filename into [root, dir, basename, ext]
function win32SplitPath(filename) {
  // Separate device+slash from tail
  var result = splitDeviceRe.exec(filename),
      device = (result[1] || '') + (result[2] || ''),
      tail = result[3] || '';
  // Split the tail into dir, basename and extension
  var result2 = splitTailRe.exec(tail),
      dir = result2[1],
      basename = result2[2],
      ext = result2[3];
  return [device, dir, basename, ext];
}

win32.parse = function(pathString) {
  if (typeof pathString !== 'string') {
    throw new TypeError(
        "Parameter 'pathString' must be a string, not " + typeof pathString
    );
  }
  var allParts = win32SplitPath(pathString);
  if (!allParts || allParts.length !== 4) {
    throw new TypeError("Invalid path '" + pathString + "'");
  }
  return {
    root: allParts[0],
    dir: allParts[0] + allParts[1].slice(0, -1),
    base: allParts[2],
    ext: allParts[3],
    name: allParts[2].slice(0, allParts[2].length - allParts[3].length)
  };
};



// Split a filename into [root, dir, basename, ext], unix version
// 'root' is just a slash, or nothing.
var splitPathRe =
    /^(\/?|)([\s\S]*?)((?:\.{1,2}|[^\/]+?|)(\.[^.\/]*|))(?:[\/]*)$/;
var posix = {};


function posixSplitPath(filename) {
  return splitPathRe.exec(filename).slice(1);
}


posix.parse = function(pathString) {
  if (typeof pathString !== 'string') {
    throw new TypeError(
        "Parameter 'pathString' must be a string, not " + typeof pathString
    );
  }
  var allParts = posixSplitPath(pathString);
  if (!allParts || allParts.length !== 4) {
    throw new TypeError("Invalid path '" + pathString + "'");
  }
  allParts[1] = allParts[1] || '';
  allParts[2] = allParts[2] || '';
  allParts[3] = allParts[3] || '';

  return {
    root: allParts[0],
    dir: allParts[0] + allParts[1].slice(0, -1),
    base: allParts[2],
    ext: allParts[3],
    name: allParts[2].slice(0, allParts[2].length - allParts[3].length)
  };
};


if (isWindows)
  module.exports = win32.parse;
else /* posix */
  module.exports = posix.parse;

module.exports.posix = posix.parse;
module.exports.win32 = win32.parse;