diff --git a/index.js b/index.js
index 285e32d..f84e820 100644
--- a/index.js
+++ b/index.js
@@ -1,3 +1,6 @@
+// 'path' module extracted from Node.js v8.11.1 (only the posix part)
+// transplited with Babel
+
 // Copyright Joyent, Inc. and other Node contributors.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a
@@ -19,206 +22,472 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-// resolves . and .. elements in a path array with directory names there
-// must be no slashes, empty elements, or device names (c:\) in the array
-// (so also no leading and trailing slashes - it does not distinguish
-// relative and absolute paths)
-function normalizeArray(parts, allowAboveRoot) {
-  // if the path tries to go above the root, `up` ends up > 0
-  var up = 0;
-  for (var i = parts.length - 1; i >= 0; i--) {
-    var last = parts[i];
-    if (last === '.') {
-      parts.splice(i, 1);
-    } else if (last === '..') {
-      parts.splice(i, 1);
-      up++;
-    } else if (up) {
-      parts.splice(i, 1);
-      up--;
-    }
+'use strict';
+
+function assertPath(path) {
+  if (typeof path !== 'string') {
+    throw new TypeError('Path must be a string. Received ' + JSON.stringify(path));
   }
+}
 
-  // if the path is allowed to go above the root, restore leading ..s
-  if (allowAboveRoot) {
-    for (; up--; up) {
-      parts.unshift('..');
+// Resolves . and .. elements in a path with directory names
+function normalizeStringPosix(path, allowAboveRoot) {
+  var res = '';
+  var lastSegmentLength = 0;
+  var lastSlash = -1;
+  var dots = 0;
+  var code;
+  for (var i = 0; i <= path.length; ++i) {
+    if (i < path.length) code = path.charCodeAt(i);else if (code === 47 /*/*/) break;else code = 47 /*/*/;
+    if (code === 47 /*/*/) {
+        if (lastSlash === i - 1 || dots === 1) {
+          // NOOP
+        } else if (lastSlash !== i - 1 && dots === 2) {
+          if (res.length < 2 || lastSegmentLength !== 2 || res.charCodeAt(res.length - 1) !== 46 /*.*/ || res.charCodeAt(res.length - 2) !== 46 /*.*/) {
+              if (res.length > 2) {
+                var lastSlashIndex = res.lastIndexOf('/');
+                if (lastSlashIndex !== res.length - 1) {
+                  if (lastSlashIndex === -1) {
+                    res = '';
+                    lastSegmentLength = 0;
+                  } else {
+                    res = res.slice(0, lastSlashIndex);
+                    lastSegmentLength = res.length - 1 - res.lastIndexOf('/');
+                  }
+                  lastSlash = i;
+                  dots = 0;
+                  continue;
+                }
+              } else if (res.length === 2 || res.length === 1) {
+                res = '';
+                lastSegmentLength = 0;
+                lastSlash = i;
+                dots = 0;
+                continue;
+              }
+            }
+          if (allowAboveRoot) {
+            if (res.length > 0) res += '/..';else res = '..';
+            lastSegmentLength = 2;
+          }
+        } else {
+          if (res.length > 0) res += '/' + path.slice(lastSlash + 1, i);else res = path.slice(lastSlash + 1, i);
+          lastSegmentLength = i - lastSlash - 1;
+        }
+        lastSlash = i;
+        dots = 0;
+      } else if (code === 46 /*.*/ && dots !== -1) {
+      ++dots;
+    } else {
+      dots = -1;
     }
   }
+  return res;
+}
 
-  return parts;
+function _format(sep, pathObject) {
+  var dir = pathObject.dir || pathObject.root;
+  var base = pathObject.base || (pathObject.name || '') + (pathObject.ext || '');
+  if (!dir) {
+    return base;
+  }
+  if (dir === pathObject.root) {
+    return dir + base;
+  }
+  return dir + sep + base;
 }
 
-// Split a filename into [root, dir, basename, ext], unix version
-// 'root' is just a slash, or nothing.
-var splitPathRe =
-    /^(\/?|)([\s\S]*?)((?:\.{1,2}|[^\/]+?|)(\.[^.\/]*|))(?:[\/]*)$/;
-var splitPath = function(filename) {
-  return splitPathRe.exec(filename).slice(1);
-};
+var posix = {
+  // path.resolve([from ...], to)
+  resolve: function resolve() {
+    var resolvedPath = '';
+    var resolvedAbsolute = false;
+    var cwd;
+
+    for (var i = arguments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
+      var path;
+      if (i >= 0) path = arguments[i];else {
+        if (cwd === undefined) cwd = process.cwd();
+        path = cwd;
+      }
+
+      assertPath(path);
+
+      // Skip empty entries
+      if (path.length === 0) {
+        continue;
+      }
+
+      resolvedPath = path + '/' + resolvedPath;
+      resolvedAbsolute = path.charCodeAt(0) === 47 /*/*/;
+    }
 
-// path.resolve([from ...], to)
-// posix version
-exports.resolve = function() {
-  var resolvedPath = '',
-      resolvedAbsolute = false;
+    // At this point the path should be resolved to a full absolute path, but
+    // handle relative paths to be safe (might happen when process.cwd() fails)
 
-  for (var i = arguments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
-    var path = (i >= 0) ? arguments[i] : process.cwd();
+    // Normalize the path
+    resolvedPath = normalizeStringPosix(resolvedPath, !resolvedAbsolute);
 
-    // Skip empty and invalid entries
-    if (typeof path !== 'string') {
-      throw new TypeError('Arguments to path.resolve must be strings');
-    } else if (!path) {
-      continue;
+    if (resolvedAbsolute) {
+      if (resolvedPath.length > 0) return '/' + resolvedPath;else return '/';
+    } else if (resolvedPath.length > 0) {
+      return resolvedPath;
+    } else {
+      return '.';
     }
+  },
 
-    resolvedPath = path + '/' + resolvedPath;
-    resolvedAbsolute = path.charAt(0) === '/';
-  }
+  normalize: function normalize(path) {
+    assertPath(path);
 
-  // At this point the path should be resolved to a full absolute path, but
-  // handle relative paths to be safe (might happen when process.cwd() fails)
+    if (path.length === 0) return '.';
 
-  // Normalize the path
-  resolvedPath = normalizeArray(filter(resolvedPath.split('/'), function(p) {
-    return !!p;
-  }), !resolvedAbsolute).join('/');
+    var isAbsolute = path.charCodeAt(0) === 47 /*/*/;
+    var trailingSeparator = path.charCodeAt(path.length - 1) === 47 /*/*/;
 
-  return ((resolvedAbsolute ? '/' : '') + resolvedPath) || '.';
-};
+    // Normalize the path
+    path = normalizeStringPosix(path, !isAbsolute);
 
-// path.normalize(path)
-// posix version
-exports.normalize = function(path) {
-  var isAbsolute = exports.isAbsolute(path),
-      trailingSlash = substr(path, -1) === '/';
+    if (path.length === 0 && !isAbsolute) path = '.';
+    if (path.length > 0 && trailingSeparator) path += '/';
 
-  // Normalize the path
-  path = normalizeArray(filter(path.split('/'), function(p) {
-    return !!p;
-  }), !isAbsolute).join('/');
+    if (isAbsolute) return '/' + path;
+    return path;
+  },
 
-  if (!path && !isAbsolute) {
-    path = '.';
-  }
-  if (path && trailingSlash) {
-    path += '/';
-  }
+  isAbsolute: function isAbsolute(path) {
+    assertPath(path);
+    return path.length > 0 && path.charCodeAt(0) === 47 /*/*/;
+  },
 
-  return (isAbsolute ? '/' : '') + path;
-};
+  join: function join() {
+    if (arguments.length === 0) return '.';
+    var joined;
+    for (var i = 0; i < arguments.length; ++i) {
+      var arg = arguments[i];
+      assertPath(arg);
+      if (arg.length > 0) {
+        if (joined === undefined) joined = arg;else joined += '/' + arg;
+      }
+    }
+    if (joined === undefined) return '.';
+    return posix.normalize(joined);
+  },
 
-// posix version
-exports.isAbsolute = function(path) {
-  return path.charAt(0) === '/';
-};
+  relative: function relative(from, to) {
+    assertPath(from);
+    assertPath(to);
 
-// posix version
-exports.join = function() {
-  var paths = Array.prototype.slice.call(arguments, 0);
-  return exports.normalize(filter(paths, function(p, index) {
-    if (typeof p !== 'string') {
-      throw new TypeError('Arguments to path.join must be strings');
-    }
-    return p;
-  }).join('/'));
-};
+    if (from === to) return '';
 
+    from = posix.resolve(from);
+    to = posix.resolve(to);
 
-// path.relative(from, to)
-// posix version
-exports.relative = function(from, to) {
-  from = exports.resolve(from).substr(1);
-  to = exports.resolve(to).substr(1);
+    if (from === to) return '';
 
-  function trim(arr) {
-    var start = 0;
-    for (; start < arr.length; start++) {
-      if (arr[start] !== '') break;
+    // Trim any leading backslashes
+    var fromStart = 1;
+    for (; fromStart < from.length; ++fromStart) {
+      if (from.charCodeAt(fromStart) !== 47 /*/*/) break;
     }
+    var fromEnd = from.length;
+    var fromLen = fromEnd - fromStart;
 
-    var end = arr.length - 1;
-    for (; end >= 0; end--) {
-      if (arr[end] !== '') break;
+    // Trim any leading backslashes
+    var toStart = 1;
+    for (; toStart < to.length; ++toStart) {
+      if (to.charCodeAt(toStart) !== 47 /*/*/) break;
     }
-
-    if (start > end) return [];
-    return arr.slice(start, end - start + 1);
-  }
-
-  var fromParts = trim(from.split('/'));
-  var toParts = trim(to.split('/'));
-
-  var length = Math.min(fromParts.length, toParts.length);
-  var samePartsLength = length;
-  for (var i = 0; i < length; i++) {
-    if (fromParts[i] !== toParts[i]) {
-      samePartsLength = i;
-      break;
+    var toEnd = to.length;
+    var toLen = toEnd - toStart;
+
+    // Compare paths to find the longest common path from root
+    var length = fromLen < toLen ? fromLen : toLen;
+    var lastCommonSep = -1;
+    var i = 0;
+    for (; i <= length; ++i) {
+      if (i === length) {
+        if (toLen > length) {
+          if (to.charCodeAt(toStart + i) === 47 /*/*/) {
+              // We get here if `from` is the exact base path for `to`.
+              // For example: from='/foo/bar'; to='/foo/bar/baz'
+              return to.slice(toStart + i + 1);
+            } else if (i === 0) {
+            // We get here if `from` is the root
+            // For example: from='/'; to='/foo'
+            return to.slice(toStart + i);
+          }
+        } else if (fromLen > length) {
+          if (from.charCodeAt(fromStart + i) === 47 /*/*/) {
+              // We get here if `to` is the exact base path for `from`.
+              // For example: from='/foo/bar/baz'; to='/foo/bar'
+              lastCommonSep = i;
+            } else if (i === 0) {
+            // We get here if `to` is the root.
+            // For example: from='/foo'; to='/'
+            lastCommonSep = 0;
+          }
+        }
+        break;
+      }
+      var fromCode = from.charCodeAt(fromStart + i);
+      var toCode = to.charCodeAt(toStart + i);
+      if (fromCode !== toCode) break;else if (fromCode === 47 /*/*/) lastCommonSep = i;
     }
-  }
-
-  var outputParts = [];
-  for (var i = samePartsLength; i < fromParts.length; i++) {
-    outputParts.push('..');
-  }
 
-  outputParts = outputParts.concat(toParts.slice(samePartsLength));
+    var out = '';
+    // Generate the relative path based on the path difference between `to`
+    // and `from`
+    for (i = fromStart + lastCommonSep + 1; i <= fromEnd; ++i) {
+      if (i === fromEnd || from.charCodeAt(i) === 47 /*/*/) {
+          if (out.length === 0) out += '..';else out += '/..';
+        }
+    }
 
-  return outputParts.join('/');
-};
+    // Lastly, append the rest of the destination (`to`) path that comes after
+    // the common path parts
+    if (out.length > 0) return out + to.slice(toStart + lastCommonSep);else {
+      toStart += lastCommonSep;
+      if (to.charCodeAt(toStart) === 47 /*/*/) ++toStart;
+      return to.slice(toStart);
+    }
+  },
+
+  _makeLong: function _makeLong(path) {
+    return path;
+  },
+
+  dirname: function dirname(path) {
+    assertPath(path);
+    if (path.length === 0) return '.';
+    var code = path.charCodeAt(0);
+    var hasRoot = code === 47 /*/*/;
+    var end = -1;
+    var matchedSlash = true;
+    for (var i = path.length - 1; i >= 1; --i) {
+      code = path.charCodeAt(i);
+      if (code === 47 /*/*/) {
+          if (!matchedSlash) {
+            end = i;
+            break;
+          }
+        } else {
+        // We saw the first non-path separator
+        matchedSlash = false;
+      }
+    }
 
-exports.sep = '/';
-exports.delimiter = ':';
+    if (end === -1) return hasRoot ? '/' : '.';
+    if (hasRoot && end === 1) return '//';
+    return path.slice(0, end);
+  },
 
-exports.dirname = function(path) {
-  var result = splitPath(path),
-      root = result[0],
-      dir = result[1];
+  basename: function basename(path, ext) {
+    if (ext !== undefined && typeof ext !== 'string') throw new TypeError('"ext" argument must be a string');
+    assertPath(path);
 
-  if (!root && !dir) {
-    // No dirname whatsoever
-    return '.';
-  }
+    var start = 0;
+    var end = -1;
+    var matchedSlash = true;
+    var i;
+
+    if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
+      if (ext.length === path.length && ext === path) return '';
+      var extIdx = ext.length - 1;
+      var firstNonSlashEnd = -1;
+      for (i = path.length - 1; i >= 0; --i) {
+        var code = path.charCodeAt(i);
+        if (code === 47 /*/*/) {
+            // If we reached a path separator that was not part of a set of path
+            // separators at the end of the string, stop now
+            if (!matchedSlash) {
+              start = i + 1;
+              break;
+            }
+          } else {
+          if (firstNonSlashEnd === -1) {
+            // We saw the first non-path separator, remember this index in case
+            // we need it if the extension ends up not matching
+            matchedSlash = false;
+            firstNonSlashEnd = i + 1;
+          }
+          if (extIdx >= 0) {
+            // Try to match the explicit extension
+            if (code === ext.charCodeAt(extIdx)) {
+              if (--extIdx === -1) {
+                // We matched the extension, so mark this as the end of our path
+                // component
+                end = i;
+              }
+            } else {
+              // Extension does not match, so our result is the entire path
+              // component
+              extIdx = -1;
+              end = firstNonSlashEnd;
+            }
+          }
+        }
+      }
+
+      if (start === end) end = firstNonSlashEnd;else if (end === -1) end = path.length;
+      return path.slice(start, end);
+    } else {
+      for (i = path.length - 1; i >= 0; --i) {
+        if (path.charCodeAt(i) === 47 /*/*/) {
+            // If we reached a path separator that was not part of a set of path
+            // separators at the end of the string, stop now
+            if (!matchedSlash) {
+              start = i + 1;
+              break;
+            }
+          } else if (end === -1) {
+          // We saw the first non-path separator, mark this as the end of our
+          // path component
+          matchedSlash = false;
+          end = i + 1;
+        }
+      }
+
+      if (end === -1) return '';
+      return path.slice(start, end);
+    }
+  },
+
+  extname: function extname(path) {
+    assertPath(path);
+    var startDot = -1;
+    var startPart = 0;
+    var end = -1;
+    var matchedSlash = true;
+    // Track the state of characters (if any) we see before our first dot and
+    // after any path separator we find
+    var preDotState = 0;
+    for (var i = path.length - 1; i >= 0; --i) {
+      var code = path.charCodeAt(i);
+      if (code === 47 /*/*/) {
+          // If we reached a path separator that was not part of a set of path
+          // separators at the end of the string, stop now
+          if (!matchedSlash) {
+            startPart = i + 1;
+            break;
+          }
+          continue;
+        }
+      if (end === -1) {
+        // We saw the first non-path separator, mark this as the end of our
+        // extension
+        matchedSlash = false;
+        end = i + 1;
+      }
+      if (code === 46 /*.*/) {
+          // If this is our first dot, mark it as the start of our extension
+          if (startDot === -1) startDot = i;else if (preDotState !== 1) preDotState = 1;
+        } else if (startDot !== -1) {
+        // We saw a non-dot and non-path separator before our dot, so we should
+        // have a good chance at having a non-empty extension
+        preDotState = -1;
+      }
+    }
 
-  if (dir) {
-    // It has a dirname, strip trailing slash
-    dir = dir.substr(0, dir.length - 1);
-  }
+    if (startDot === -1 || end === -1 ||
+    // We saw a non-dot character immediately before the dot
+    preDotState === 0 ||
+    // The (right-most) trimmed path component is exactly '..'
+    preDotState === 1 && startDot === end - 1 && startDot === startPart + 1) {
+      return '';
+    }
+    return path.slice(startDot, end);
+  },
 
-  return root + dir;
-};
+  format: function format(pathObject) {
+    if (pathObject === null || typeof pathObject === 'undefined') {
+      throw new TypeError('Parameter "pathObject" must be an object, not ' + (typeof pathObject));
+    }
+    return _format('/', pathObject);
+  },
+
+  parse: function parse(path) {
+    assertPath(path);
+
+    var ret = { root: '', dir: '', base: '', ext: '', name: '' };
+    if (path.length === 0) return ret;
+    var code = path.charCodeAt(0);
+    var isAbsolute = code === 47 /*/*/;
+    var start;
+    if (isAbsolute) {
+      ret.root = '/';
+      start = 1;
+    } else {
+      start = 0;
+    }
+    var startDot = -1;
+    var startPart = 0;
+    var end = -1;
+    var matchedSlash = true;
+    var i = path.length - 1;
+
+    // Track the state of characters (if any) we see before our first dot and
+    // after any path separator we find
+    var preDotState = 0;
+
+    // Get non-dir info
+    for (; i >= start; --i) {
+      code = path.charCodeAt(i);
+      if (code === 47 /*/*/) {
+          // If we reached a path separator that was not part of a set of path
+          // separators at the end of the string, stop now
+          if (!matchedSlash) {
+            startPart = i + 1;
+            break;
+          }
+          continue;
+        }
+      if (end === -1) {
+        // We saw the first non-path separator, mark this as the end of our
+        // extension
+        matchedSlash = false;
+        end = i + 1;
+      }
+      if (code === 46 /*.*/) {
+          // If this is our first dot, mark it as the start of our extension
+          if (startDot === -1) startDot = i;else if (preDotState !== 1) preDotState = 1;
+        } else if (startDot !== -1) {
+        // We saw a non-dot and non-path separator before our dot, so we should
+        // have a good chance at having a non-empty extension
+        preDotState = -1;
+      }
+    }
 
+    if (startDot === -1 || end === -1 ||
+    // We saw a non-dot character immediately before the dot
+    preDotState === 0 ||
+    // The (right-most) trimmed path component is exactly '..'
+    preDotState === 1 && startDot === end - 1 && startDot === startPart + 1) {
+      if (end !== -1) {
+        if (startPart === 0 && isAbsolute) ret.base = ret.name = path.slice(1, end);else ret.base = ret.name = path.slice(startPart, end);
+      }
+    } else {
+      if (startPart === 0 && isAbsolute) {
+        ret.name = path.slice(1, startDot);
+        ret.base = path.slice(1, end);
+      } else {
+        ret.name = path.slice(startPart, startDot);
+        ret.base = path.slice(startPart, end);
+      }
+      ret.ext = path.slice(startDot, end);
+    }
 
-exports.basename = function(path, ext) {
-  var f = splitPath(path)[2];
-  // TODO: make this comparison case-insensitive on windows?
-  if (ext && f.substr(-1 * ext.length) === ext) {
-    f = f.substr(0, f.length - ext.length);
-  }
-  return f;
-};
+    if (startPart > 0) ret.dir = path.slice(0, startPart - 1);else if (isAbsolute) ret.dir = '/';
 
+    return ret;
+  },
 
-exports.extname = function(path) {
-  return splitPath(path)[3];
+  sep: '/',
+  delimiter: ':',
+  win32: null,
+  posix: null
 };
 
-function filter (xs, f) {
-    if (xs.filter) return xs.filter(f);
-    var res = [];
-    for (var i = 0; i < xs.length; i++) {
-        if (f(xs[i], i, xs)) res.push(xs[i]);
-    }
-    return res;
-}
+posix.posix = posix;
 
-// String.prototype.substr - negative index don't work in IE8
-var substr = 'ab'.substr(-1) === 'b'
-    ? function (str, start, len) { return str.substr(start, len) }
-    : function (str, start, len) {
-        if (start < 0) start = str.length + start;
-        return str.substr(start, len);
-    }
-;
+module.exports = posix;