Move posix and win implementations in fs/path/mod.ts to separate file (denoland/deno_std#397)

Original: https://github.com/denoland/deno_std/commit/b6a7b78535188a83b3f865d2389e5be3f0c12ead

4 files changed, 1453 insertions, 1428 deletions

diff --git a/fs/path/mod.ts b/fs/path/mod.ts
index ffcc721a9..660c061d6 100644
--- a/fs/path/mod.ts
+++ b/fs/path/mod.ts
@@ -1,1431 +1,25 @@
 // Copyright the Browserify authors. MIT License.
 // Ported from https://github.com/browserify/path-browserify/
 
-const { cwd, env } = Deno;
-import { FormatInputPathObject, ParsedPath } from "./interface.ts";
-import {
-  isWindows,
-  CHAR_UPPERCASE_A,
-  CHAR_LOWERCASE_A,
-  CHAR_UPPERCASE_Z,
-  CHAR_LOWERCASE_Z,
-  CHAR_DOT,
-  CHAR_FORWARD_SLASH,
-  CHAR_BACKWARD_SLASH,
-  CHAR_COLON,
-  CHAR_QUESTION_MARK
-} from "./constants.ts";
-
-function assertPath(path: string): void {
-  if (typeof path !== "string") {
-    throw new TypeError(
-      `Path must be a string. Received ${JSON.stringify(path)}`
-    );
-  }
-}
-
-function isPosixPathSeparator(code: number): boolean {
-  return code === CHAR_FORWARD_SLASH;
-}
-
-function isPathSeparator(code: number): boolean {
-  return isPosixPathSeparator(code) || code === CHAR_BACKWARD_SLASH;
-}
-
-function isWindowsDeviceRoot(code: number): boolean {
-  return (
-    (code >= CHAR_LOWERCASE_A && code <= CHAR_LOWERCASE_Z) ||
-    (code >= CHAR_UPPERCASE_A && code <= CHAR_UPPERCASE_Z)
-  );
-}
-
-// Resolves . and .. elements in a path with directory names
-function normalizeString(
-  path: string,
-  allowAboveRoot: boolean,
-  separator: string,
-  isPathSeparator: (code: number) => boolean
-): string {
-  let res = "";
-  let lastSegmentLength = 0;
-  let lastSlash = -1;
-  let dots = 0;
-  let code: number;
-  for (let i = 0, len = path.length; i <= len; ++i) {
-    if (i < len) code = path.charCodeAt(i);
-    else if (isPathSeparator(code)) break;
-    else code = CHAR_FORWARD_SLASH;
-
-    if (isPathSeparator(code)) {
-      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) !== CHAR_DOT ||
-          res.charCodeAt(res.length - 2) !== CHAR_DOT
-        ) {
-          if (res.length > 2) {
-            const lastSlashIndex = res.lastIndexOf(separator);
-            if (lastSlashIndex === -1) {
-              res = "";
-              lastSegmentLength = 0;
-            } else {
-              res = res.slice(0, lastSlashIndex);
-              lastSegmentLength = res.length - 1 - res.lastIndexOf(separator);
-            }
-            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 += `${separator}..`;
-          else res = "..";
-          lastSegmentLength = 2;
-        }
-      } else {
-        if (res.length > 0) res += separator + path.slice(lastSlash + 1, i);
-        else res = path.slice(lastSlash + 1, i);
-        lastSegmentLength = i - lastSlash - 1;
-      }
-      lastSlash = i;
-      dots = 0;
-    } else if (code === CHAR_DOT && dots !== -1) {
-      ++dots;
-    } else {
-      dots = -1;
-    }
-  }
-  return res;
-}
-
-function _format(sep: string, pathObject: FormatInputPathObject): string {
-  const dir: string | null = pathObject.dir || pathObject.root;
-  const base: string =
-    pathObject.base || (pathObject.name || "") + (pathObject.ext || "");
-  if (!dir) return base;
-  if (dir === pathObject.root) return dir + base;
-  return dir + sep + base;
-}
-
-export const win32 = {
-  // path.resolve([from ...], to)
-  resolve(...pathSegments: string[]): string {
-    let resolvedDevice = "";
-    let resolvedTail = "";
-    let resolvedAbsolute = false;
-
-    for (let i = pathSegments.length - 1; i >= -1; i--) {
-      let path: string;
-      if (i >= 0) {
-        path = pathSegments[i];
-      } else if (!resolvedDevice) {
-        path = cwd();
-      } else {
-        // Windows has the concept of drive-specific current working
-        // directories. If we've resolved a drive letter but not yet an
-        // absolute path, get cwd for that drive, or the process cwd if
-        // the drive cwd is not available. We're sure the device is not
-        // a UNC path at this points, because UNC paths are always absolute.
-        path = env()[`=${resolvedDevice}`] || cwd();
-
-        // Verify that a cwd was found and that it actually points
-        // to our drive. If not, default to the drive's root.
-        if (
-          path === undefined ||
-          path.slice(0, 3).toLowerCase() !== `${resolvedDevice.toLowerCase()}\\`
-        ) {
-          path = `${resolvedDevice}\\`;
-        }
-      }
-
-      assertPath(path);
-
-      const len = path.length;
-
-      // Skip empty entries
-      if (len === 0) continue;
-
-      let rootEnd = 0;
-      let device = "";
-      let isAbsolute = false;
-      const code = path.charCodeAt(0);
-
-      // Try to match a root
-      if (len > 1) {
-        if (isPathSeparator(code)) {
-          // Possible UNC root
-
-          // If we started with a separator, we know we at least have an
-          // absolute path of some kind (UNC or otherwise)
-          isAbsolute = true;
-
-          if (isPathSeparator(path.charCodeAt(1))) {
-            // Matched double path separator at beginning
-            let j = 2;
-            let last = j;
-            // Match 1 or more non-path separators
-            for (; j < len; ++j) {
-              if (isPathSeparator(path.charCodeAt(j))) break;
-            }
-            if (j < len && j !== last) {
-              const firstPart = path.slice(last, j);
-              // Matched!
-              last = j;
-              // Match 1 or more path separators
-              for (; j < len; ++j) {
-                if (!isPathSeparator(path.charCodeAt(j))) break;
-              }
-              if (j < len && j !== last) {
-                // Matched!
-                last = j;
-                // Match 1 or more non-path separators
-                for (; j < len; ++j) {
-                  if (isPathSeparator(path.charCodeAt(j))) break;
-                }
-                if (j === len) {
-                  // We matched a UNC root only
-                  device = `\\\\${firstPart}\\${path.slice(last)}`;
-                  rootEnd = j;
-                } else if (j !== last) {
-                  // We matched a UNC root with leftovers
-
-                  device = `\\\\${firstPart}\\${path.slice(last, j)}`;
-                  rootEnd = j;
-                }
-              }
-            }
-          } else {
-            rootEnd = 1;
-          }
-        } else if (isWindowsDeviceRoot(code)) {
-          // Possible device root
-
-          if (path.charCodeAt(1) === CHAR_COLON) {
-            device = path.slice(0, 2);
-            rootEnd = 2;
-            if (len > 2) {
-              if (isPathSeparator(path.charCodeAt(2))) {
-                // Treat separator following drive name as an absolute path
-                // indicator
-                isAbsolute = true;
-                rootEnd = 3;
-              }
-            }
-          }
-        }
-      } else if (isPathSeparator(code)) {
-        // `path` contains just a path separator
-        rootEnd = 1;
-        isAbsolute = true;
-      }
-
-      if (
-        device.length > 0 &&
-        resolvedDevice.length > 0 &&
-        device.toLowerCase() !== resolvedDevice.toLowerCase()
-      ) {
-        // This path points to another device so it is not applicable
-        continue;
-      }
-
-      if (resolvedDevice.length === 0 && device.length > 0) {
-        resolvedDevice = device;
-      }
-      if (!resolvedAbsolute) {
-        resolvedTail = `${path.slice(rootEnd)}\\${resolvedTail}`;
-        resolvedAbsolute = isAbsolute;
-      }
-
-      if (resolvedAbsolute && resolvedDevice.length > 0) break;
-    }
-
-    // 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)
-
-    // Normalize the tail path
-    resolvedTail = normalizeString(
-      resolvedTail,
-      !resolvedAbsolute,
-      "\\",
-      isPathSeparator
-    );
-
-    return (
-      resolvedDevice + (resolvedAbsolute ? "\\" : "") + resolvedTail || "."
-    );
-  },
-
-  normalize(path: string): string {
-    assertPath(path);
-    const len = path.length;
-    if (len === 0) return ".";
-    let rootEnd = 0;
-    let device: string;
-    let isAbsolute = false;
-    const code = path.charCodeAt(0);
-
-    // Try to match a root
-    if (len > 1) {
-      if (isPathSeparator(code)) {
-        // Possible UNC root
-
-        // If we started with a separator, we know we at least have an absolute
-        // path of some kind (UNC or otherwise)
-        isAbsolute = true;
-
-        if (isPathSeparator(path.charCodeAt(1))) {
-          // Matched double path separator at beginning
-          let j = 2;
-          let last = j;
-          // Match 1 or more non-path separators
-          for (; j < len; ++j) {
-            if (isPathSeparator(path.charCodeAt(j))) break;
-          }
-          if (j < len && j !== last) {
-            const firstPart = path.slice(last, j);
-            // Matched!
-            last = j;
-            // Match 1 or more path separators
-            for (; j < len; ++j) {
-              if (!isPathSeparator(path.charCodeAt(j))) break;
-            }
-            if (j < len && j !== last) {
-              // Matched!
-              last = j;
-              // Match 1 or more non-path separators
-              for (; j < len; ++j) {
-                if (isPathSeparator(path.charCodeAt(j))) break;
-              }
-              if (j === len) {
-                // We matched a UNC root only
-                // Return the normalized version of the UNC root since there
-                // is nothing left to process
-
-                return `\\\\${firstPart}\\${path.slice(last)}\\`;
-              } else if (j !== last) {
-                // We matched a UNC root with leftovers
-
-                device = `\\\\${firstPart}\\${path.slice(last, j)}`;
-                rootEnd = j;
-              }
-            }
-          }
-        } else {
-          rootEnd = 1;
-        }
-      } else if (isWindowsDeviceRoot(code)) {
-        // Possible device root
-
-        if (path.charCodeAt(1) === CHAR_COLON) {
-          device = path.slice(0, 2);
-          rootEnd = 2;
-          if (len > 2) {
-            if (isPathSeparator(path.charCodeAt(2))) {
-              // Treat separator following drive name as an absolute path
-              // indicator
-              isAbsolute = true;
-              rootEnd = 3;
-            }
-          }
-        }
-      }
-    } else if (isPathSeparator(code)) {
-      // `path` contains just a path separator, exit early to avoid unnecessary
-      // work
-      return "\\";
-    }
-
-    let tail: string;
-    if (rootEnd < len) {
-      tail = normalizeString(
-        path.slice(rootEnd),
-        !isAbsolute,
-        "\\",
-        isPathSeparator
-      );
-    } else {
-      tail = "";
-    }
-    if (tail.length === 0 && !isAbsolute) tail = ".";
-    if (tail.length > 0 && isPathSeparator(path.charCodeAt(len - 1)))
-      tail += "\\";
-    if (device === undefined) {
-      if (isAbsolute) {
-        if (tail.length > 0) return `\\${tail}`;
-        else return "\\";
-      } else if (tail.length > 0) {
-        return tail;
-      } else {
-        return "";
-      }
-    } else if (isAbsolute) {
-      if (tail.length > 0) return `${device}\\${tail}`;
-      else return `${device}\\`;
-    } else if (tail.length > 0) {
-      return device + tail;
-    } else {
-      return device;
-    }
-  },
-
-  isAbsolute(path: string): boolean {
-    assertPath(path);
-    const len = path.length;
-    if (len === 0) return false;
-
-    const code = path.charCodeAt(0);
-    if (isPathSeparator(code)) {
-      return true;
-    } else if (isWindowsDeviceRoot(code)) {
-      // Possible device root
-
-      if (len > 2 && path.charCodeAt(1) === CHAR_COLON) {
-        if (isPathSeparator(path.charCodeAt(2))) return true;
-      }
-    }
-    return false;
-  },
-
-  join(...paths: string[]): string {
-    const pathsCount = paths.length;
-    if (pathsCount === 0) return ".";
-
-    let joined: string;
-    let firstPart: string;
-    for (let i = 0; i < pathsCount; ++i) {
-      let path = paths[i];
-      assertPath(path);
-      if (path.length > 0) {
-        if (joined === undefined) joined = firstPart = path;
-        else joined += `\\${path}`;
-      }
-    }
-
-    if (joined === undefined) return ".";
-
-    // Make sure that the joined path doesn't start with two slashes, because
-    // normalize() will mistake it for an UNC path then.
-    //
-    // This step is skipped when it is very clear that the user actually
-    // intended to point at an UNC path. This is assumed when the first
-    // non-empty string arguments starts with exactly two slashes followed by
-    // at least one more non-slash character.
-    //
-    // Note that for normalize() to treat a path as an UNC path it needs to
-    // have at least 2 components, so we don't filter for that here.
-    // This means that the user can use join to construct UNC paths from
-    // a server name and a share name; for example:
-    //   path.join('//server', 'share') -> '\\\\server\\share\\')
-    let needsReplace = true;
-    let slashCount = 0;
-    if (isPathSeparator(firstPart.charCodeAt(0))) {
-      ++slashCount;
-      const firstLen = firstPart.length;
-      if (firstLen > 1) {
-        if (isPathSeparator(firstPart.charCodeAt(1))) {
-          ++slashCount;
-          if (firstLen > 2) {
-            if (isPathSeparator(firstPart.charCodeAt(2))) ++slashCount;
-            else {
-              // We matched a UNC path in the first part
-              needsReplace = false;
-            }
-          }
-        }
-      }
-    }
-    if (needsReplace) {
-      // Find any more consecutive slashes we need to replace
-      for (; slashCount < joined.length; ++slashCount) {
-        if (!isPathSeparator(joined.charCodeAt(slashCount))) break;
-      }
-
-      // Replace the slashes if needed
-      if (slashCount >= 2) joined = `\\${joined.slice(slashCount)}`;
-    }
-
-    return win32.normalize(joined);
-  },
-
-  // It will solve the relative path from `from` to `to`, for instance:
-  //  from = 'C:\\orandea\\test\\aaa'
-  //  to = 'C:\\orandea\\impl\\bbb'
-  // The output of the function should be: '..\\..\\impl\\bbb'
-  relative(from: string, to: string): string {
-    assertPath(from);
-    assertPath(to);
-
-    if (from === to) return "";
-
-    let fromOrig = win32.resolve(from);
-    let toOrig = win32.resolve(to);
-
-    if (fromOrig === toOrig) return "";
-
-    from = fromOrig.toLowerCase();
-    to = toOrig.toLowerCase();
-
-    if (from === to) return "";
-
-    // Trim any leading backslashes
-    let fromStart = 0;
-    let fromEnd = from.length;
-    for (; fromStart < fromEnd; ++fromStart) {
-      if (from.charCodeAt(fromStart) !== CHAR_BACKWARD_SLASH) break;
-    }
-    // Trim trailing backslashes (applicable to UNC paths only)
-    for (; fromEnd - 1 > fromStart; --fromEnd) {
-      if (from.charCodeAt(fromEnd - 1) !== CHAR_BACKWARD_SLASH) break;
-    }
-    let fromLen = fromEnd - fromStart;
-
-    // Trim any leading backslashes
-    let toStart = 0;
-    let toEnd = to.length;
-    for (; toStart < toEnd; ++toStart) {
-      if (to.charCodeAt(toStart) !== CHAR_BACKWARD_SLASH) break;
-    }
-    // Trim trailing backslashes (applicable to UNC paths only)
-    for (; toEnd - 1 > toStart; --toEnd) {
-      if (to.charCodeAt(toEnd - 1) !== CHAR_BACKWARD_SLASH) break;
-    }
-    let toLen = toEnd - toStart;
-
-    // Compare paths to find the longest common path from root
-    let length = fromLen < toLen ? fromLen : toLen;
-    let lastCommonSep = -1;
-    let i = 0;
-    for (; i <= length; ++i) {
-      if (i === length) {
-        if (toLen > length) {
-          if (to.charCodeAt(toStart + i) === CHAR_BACKWARD_SLASH) {
-            // We get here if `from` is the exact base path for `to`.
-            // For example: from='C:\\foo\\bar'; to='C:\\foo\\bar\\baz'
-            return toOrig.slice(toStart + i + 1);
-          } else if (i === 2) {
-            // We get here if `from` is the device root.
-            // For example: from='C:\\'; to='C:\\foo'
-            return toOrig.slice(toStart + i);
-          }
-        }
-        if (fromLen > length) {
-          if (from.charCodeAt(fromStart + i) === CHAR_BACKWARD_SLASH) {
-            // We get here if `to` is the exact base path for `from`.
-            // For example: from='C:\\foo\\bar'; to='C:\\foo'
-            lastCommonSep = i;
-          } else if (i === 2) {
-            // We get here if `to` is the device root.
-            // For example: from='C:\\foo\\bar'; to='C:\\'
-            lastCommonSep = 3;
-          }
-        }
-        break;
-      }
-      let fromCode = from.charCodeAt(fromStart + i);
-      let toCode = to.charCodeAt(toStart + i);
-      if (fromCode !== toCode) break;
-      else if (fromCode === CHAR_BACKWARD_SLASH) lastCommonSep = i;
-    }
-
-    // We found a mismatch before the first common path separator was seen, so
-    // return the original `to`.
-    if (i !== length && lastCommonSep === -1) {
-      return toOrig;
-    }
-
-    let out = "";
-    if (lastCommonSep === -1) lastCommonSep = 0;
-    // 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) === CHAR_BACKWARD_SLASH) {
-        if (out.length === 0) out += "..";
-        else out += "\\..";
-      }
-    }
-
-    // Lastly, append the rest of the destination (`to`) path that comes after
-    // the common path parts
-    if (out.length > 0)
-      return out + toOrig.slice(toStart + lastCommonSep, toEnd);
-    else {
-      toStart += lastCommonSep;
-      if (toOrig.charCodeAt(toStart) === CHAR_BACKWARD_SLASH) ++toStart;
-      return toOrig.slice(toStart, toEnd);
-    }
-  },
-
-  toNamespacedPath(path: string): string {
-    // Note: this will *probably* throw somewhere.
-    if (typeof path !== "string") return path;
-    if (path.length === 0) return "";
-
-    const resolvedPath = win32.resolve(path);
-
-    if (resolvedPath.length >= 3) {
-      if (resolvedPath.charCodeAt(0) === CHAR_BACKWARD_SLASH) {
-        // Possible UNC root
-
-        if (resolvedPath.charCodeAt(1) === CHAR_BACKWARD_SLASH) {
-          const code = resolvedPath.charCodeAt(2);
-          if (code !== CHAR_QUESTION_MARK && code !== CHAR_DOT) {
-            // Matched non-long UNC root, convert the path to a long UNC path
-            return `\\\\?\\UNC\\${resolvedPath.slice(2)}`;
-          }
-        }
-      } else if (isWindowsDeviceRoot(resolvedPath.charCodeAt(0))) {
-        // Possible device root
-
-        if (
-          resolvedPath.charCodeAt(1) === CHAR_COLON &&
-          resolvedPath.charCodeAt(2) === CHAR_BACKWARD_SLASH
-        ) {
-          // Matched device root, convert the path to a long UNC path
-          return `\\\\?\\${resolvedPath}`;
-        }
-      }
-    }
-
-    return path;
-  },
-
-  dirname(path: string): string {
-    assertPath(path);
-    const len = path.length;
-    if (len === 0) return ".";
-    let rootEnd = -1;
-    let end = -1;
-    let matchedSlash = true;
-    let offset = 0;
-    const code = path.charCodeAt(0);
-
-    // Try to match a root
-    if (len > 1) {
-      if (isPathSeparator(code)) {
-        // Possible UNC root
-
-        rootEnd = offset = 1;
-
-        if (isPathSeparator(path.charCodeAt(1))) {
-          // Matched double path separator at beginning
-          let j = 2;
-          let last = j;
-          // Match 1 or more non-path separators
-          for (; j < len; ++j) {
-            if (isPathSeparator(path.charCodeAt(j))) break;
-          }
-          if (j < len && j !== last) {
-            // Matched!
-            last = j;
-            // Match 1 or more path separators
-            for (; j < len; ++j) {
-              if (!isPathSeparator(path.charCodeAt(j))) break;
-            }
-            if (j < len && j !== last) {
-              // Matched!
-              last = j;
-              // Match 1 or more non-path separators
-              for (; j < len; ++j) {
-                if (isPathSeparator(path.charCodeAt(j))) break;
-              }
-              if (j === len) {
-                // We matched a UNC root only
-                return path;
-              }
-              if (j !== last) {
-                // We matched a UNC root with leftovers
-
-                // Offset by 1 to include the separator after the UNC root to
-                // treat it as a "normal root" on top of a (UNC) root
-                rootEnd = offset = j + 1;
-              }
-            }
-          }
-        }
-      } else if (isWindowsDeviceRoot(code)) {
-        // Possible device root
-
-        if (path.charCodeAt(1) === CHAR_COLON) {
-          rootEnd = offset = 2;
-          if (len > 2) {
-            if (isPathSeparator(path.charCodeAt(2))) rootEnd = offset = 3;
-          }
-        }
-      }
-    } else if (isPathSeparator(code)) {
-      // `path` contains just a path separator, exit early to avoid
-      // unnecessary work
-      return path;
-    }
-
-    for (let i = len - 1; i >= offset; --i) {
-      if (isPathSeparator(path.charCodeAt(i))) {
-        if (!matchedSlash) {
-          end = i;
-          break;
-        }
-      } else {
-        // We saw the first non-path separator
-        matchedSlash = false;
-      }
-    }
-
-    if (end === -1) {
-      if (rootEnd === -1) return ".";
-      else end = rootEnd;
-    }
-    return path.slice(0, end);
-  },
-
-  basename(path: string, ext = ""): string {
-    if (ext !== undefined && typeof ext !== "string")
-      throw new TypeError('"ext" argument must be a string');
-
-    assertPath(path);
-
-    let start = 0;
-    let end = -1;
-    let matchedSlash = true;
-    let i: number;
-
-    // Check for a drive letter prefix so as not to mistake the following
-    // path separator as an extra separator at the end of the path that can be
-    // disregarded
-    if (path.length >= 2) {
-      const drive = path.charCodeAt(0);
-      if (isWindowsDeviceRoot(drive)) {
-        if (path.charCodeAt(1) === CHAR_COLON) start = 2;
-      }
-    }
-
-    if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
-      if (ext.length === path.length && ext === path) return "";
-      let extIdx = ext.length - 1;
-      let firstNonSlashEnd = -1;
-      for (i = path.length - 1; i >= start; --i) {
-        const code = path.charCodeAt(i);
-        if (isPathSeparator(code)) {
-          // 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 >= start; --i) {
-        if (isPathSeparator(path.charCodeAt(i))) {
-          // 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(path: string): string {
-    assertPath(path);
-    let start = 0;
-    let startDot = -1;
-    let startPart = 0;
-    let end = -1;
-    let matchedSlash = true;
-    // Track the state of characters (if any) we see before our first dot and
-    // after any path separator we find
-    let preDotState = 0;
-
-    // Check for a drive letter prefix so as not to mistake the following
-    // path separator as an extra separator at the end of the path that can be
-    // disregarded
-
-    if (
-      path.length >= 2 &&
-      path.charCodeAt(1) === CHAR_COLON &&
-      isWindowsDeviceRoot(path.charCodeAt(0))
-    ) {
-      start = startPart = 2;
-    }
-
-    for (let i = path.length - 1; i >= start; --i) {
-      const code = path.charCodeAt(i);
-      if (isPathSeparator(code)) {
-        // 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 === CHAR_DOT) {
-        // 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)
-    ) {
-      return "";
-    }
-    return path.slice(startDot, end);
-  },
-
-  format(pathObject: FormatInputPathObject): string {
-    if (pathObject === null || typeof pathObject !== "object") {
-      throw new TypeError(
-        `The "pathObject" argument must be of type Object. Received type ${typeof pathObject}`
-      );
-    }
-    return _format("\\", pathObject);
-  },
-
-  parse(path: string): ParsedPath {
-    assertPath(path);
-
-    let ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
-
-    const len = path.length;
-    if (len === 0) return ret;
-
-    let rootEnd = 0;
-    let code = path.charCodeAt(0);
-
-    // Try to match a root
-    if (len > 1) {
-      if (isPathSeparator(code)) {
-        // Possible UNC root
-
-        rootEnd = 1;
-        if (isPathSeparator(path.charCodeAt(1))) {
-          // Matched double path separator at beginning
-          let j = 2;
-          let last = j;
-          // Match 1 or more non-path separators
-          for (; j < len; ++j) {
-            if (isPathSeparator(path.charCodeAt(j))) break;
-          }
-          if (j < len && j !== last) {
-            // Matched!
-            last = j;
-            // Match 1 or more path separators
-            for (; j < len; ++j) {
-              if (!isPathSeparator(path.charCodeAt(j))) break;
-            }
-            if (j < len && j !== last) {
-              // Matched!
-              last = j;
-              // Match 1 or more non-path separators
-              for (; j < len; ++j) {
-                if (isPathSeparator(path.charCodeAt(j))) break;
-              }
-              if (j === len) {
-                // We matched a UNC root only
-
-                rootEnd = j;
-              } else if (j !== last) {
-                // We matched a UNC root with leftovers
-
-                rootEnd = j + 1;
-              }
-            }
-          }
-        }
-      } else if (isWindowsDeviceRoot(code)) {
-        // Possible device root
-
-        if (path.charCodeAt(1) === CHAR_COLON) {
-          rootEnd = 2;
-          if (len > 2) {
-            if (isPathSeparator(path.charCodeAt(2))) {
-              if (len === 3) {
-                // `path` contains just a drive root, exit early to avoid
-                // unnecessary work
-                ret.root = ret.dir = path;
-                return ret;
-              }
-              rootEnd = 3;
-            }
-          } else {
-            // `path` contains just a drive root, exit early to avoid
-            // unnecessary work
-            ret.root = ret.dir = path;
-            return ret;
-          }
-        }
-      }
-    } else if (isPathSeparator(code)) {
-      // `path` contains just a path separator, exit early to avoid
-      // unnecessary work
-      ret.root = ret.dir = path;
-      return ret;
-    }
-
-    if (rootEnd > 0) ret.root = path.slice(0, rootEnd);
-
-    let startDot = -1;
-    let startPart = rootEnd;
-    let end = -1;
-    let matchedSlash = true;
-    let i = path.length - 1;
-
-    // Track the state of characters (if any) we see before our first dot and
-    // after any path separator we find
-    let preDotState = 0;
-
-    // Get non-dir info
-    for (; i >= rootEnd; --i) {
-      code = path.charCodeAt(i);
-      if (isPathSeparator(code)) {
-        // 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 === CHAR_DOT) {
-        // 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) {
-        ret.base = ret.name = path.slice(startPart, end);
-      }
-    } else {
-      ret.name = path.slice(startPart, startDot);
-      ret.base = path.slice(startPart, end);
-      ret.ext = path.slice(startDot, end);
-    }
-
-    // If the directory is the root, use the entire root as the `dir` including
-    // the trailing slash if any (`C:\abc` -> `C:\`). Otherwise, strip out the
-    // trailing slash (`C:\abc\def` -> `C:\abc`).
-    if (startPart > 0 && startPart !== rootEnd) {
-      ret.dir = path.slice(0, startPart - 1);
-    } else ret.dir = ret.root;
-
-    return ret;
-  },
-
-  sep: "\\",
-  delimiter: ";",
-  win32: null,
-  posix: null
-};
-
-export const posix = {
-  // path.resolve([from ...], to)
-  resolve(...pathSegments: string[]): string {
-    let resolvedPath = "";
-    let resolvedAbsolute = false;
-
-    for (let i = pathSegments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
-      let path: string;
-
-      if (i >= 0) path = pathSegments[i];
-      else path = cwd();
-
-      assertPath(path);
-
-      // Skip empty entries
-      if (path.length === 0) {
-        continue;
-      }
-
-      resolvedPath = `${path}/${resolvedPath}`;
-      resolvedAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
-    }
-
-    // At this point the path should be resolved to a full absolute path, but
-    // handle relative paths to be safe (might happen when process.cwd() fails)
-
-    // Normalize the path
-    resolvedPath = normalizeString(
-      resolvedPath,
-      !resolvedAbsolute,
-      "/",
-      isPosixPathSeparator
-    );
-
-    if (resolvedAbsolute) {
-      if (resolvedPath.length > 0) return `/${resolvedPath}`;
-      else return "/";
-    } else if (resolvedPath.length > 0) return resolvedPath;
-    else return ".";
-  },
-
-  normalize(path: string): string {
-    assertPath(path);
-
-    if (path.length === 0) return ".";
-
-    const isAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
-    const trailingSeparator =
-      path.charCodeAt(path.length - 1) === CHAR_FORWARD_SLASH;
-
-    // Normalize the path
-    path = normalizeString(path, !isAbsolute, "/", isPosixPathSeparator);
-
-    if (path.length === 0 && !isAbsolute) path = ".";
-    if (path.length > 0 && trailingSeparator) path += "/";
-
-    if (isAbsolute) return `/${path}`;
-    return path;
-  },
-
-  isAbsolute(path: string): boolean {
-    assertPath(path);
-    return path.length > 0 && path.charCodeAt(0) === CHAR_FORWARD_SLASH;
-  },
-
-  join(...paths: string[]): string {
-    if (paths.length === 0) return ".";
-    let joined: string | undefined;
-    for (let i = 0, len = paths.length; i < len; ++i) {
-      let path = paths[i];
-      assertPath(path);
-      if (path.length > 0) {
-        if (!joined) joined = path;
-        else joined += `/${path}`;
-      }
-    }
-    if (!joined) return ".";
-    return posix.normalize(joined);
-  },
-
-  relative(from: string, to: string): string {
-    assertPath(from);
-    assertPath(to);
-
-    if (from === to) return "";
-
-    from = posix.resolve(from);
-    to = posix.resolve(to);
-
-    if (from === to) return "";
-
-    // Trim any leading backslashes
-    let fromStart = 1;
-    let fromEnd = from.length;
-    for (; fromStart < fromEnd; ++fromStart) {
-      if (from.charCodeAt(fromStart) !== CHAR_FORWARD_SLASH) break;
-    }
-    let fromLen = fromEnd - fromStart;
-
-    // Trim any leading backslashes
-    let toStart = 1;
-    const toEnd = to.length;
-    for (; toStart < toEnd; ++toStart) {
-      if (to.charCodeAt(toStart) !== CHAR_FORWARD_SLASH) break;
-    }
-    let toLen = toEnd - toStart;
-
-    // Compare paths to find the longest common path from root
-    let length = fromLen < toLen ? fromLen : toLen;
-    let lastCommonSep = -1;
-    let i = 0;
-    for (; i <= length; ++i) {
-      if (i === length) {
-        if (toLen > length) {
-          if (to.charCodeAt(toStart + i) === CHAR_FORWARD_SLASH) {
-            // 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) === CHAR_FORWARD_SLASH) {
-            // 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;
-      }
-      let fromCode = from.charCodeAt(fromStart + i);
-      let toCode = to.charCodeAt(toStart + i);
-      if (fromCode !== toCode) break;
-      else if (fromCode === CHAR_FORWARD_SLASH) lastCommonSep = i;
-    }
-
-    let 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) === CHAR_FORWARD_SLASH) {
-        if (out.length === 0) out += "..";
-        else out += "/..";
-      }
-    }
-
-    // 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) === CHAR_FORWARD_SLASH) ++toStart;
-      return to.slice(toStart);
-    }
-  },
-
-  toNamespacedPath(path: string): string {
-    // Non-op on posix systems
-    return path;
-  },
-
-  dirname(path: string): string {
-    assertPath(path);
-    if (path.length === 0) return ".";
-    const hasRoot = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
-    let end = -1;
-    let matchedSlash = true;
-    for (let i = path.length - 1; i >= 1; --i) {
-      if (path.charCodeAt(i) === CHAR_FORWARD_SLASH) {
-        if (!matchedSlash) {
-          end = i;
-          break;
-        }
-      } else {
-        // We saw the first non-path separator
-        matchedSlash = false;
-      }
-    }
-
-    if (end === -1) return hasRoot ? "/" : ".";
-    if (hasRoot && end === 1) return "//";
-    return path.slice(0, end);
-  },
-
-  basename(path: string, ext = ""): string {
-    if (ext !== undefined && typeof ext !== "string")
-      throw new TypeError('"ext" argument must be a string');
-    assertPath(path);
-
-    let start = 0;
-    let end = -1;
-    let matchedSlash = true;
-    let i: number;
-
-    if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
-      if (ext.length === path.length && ext === path) return "";
-      let extIdx = ext.length - 1;
-      let firstNonSlashEnd = -1;
-      for (i = path.length - 1; i >= 0; --i) {
-        const code = path.charCodeAt(i);
-        if (code === CHAR_FORWARD_SLASH) {
-          // 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) === CHAR_FORWARD_SLASH) {
-          // 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(path: string): string {
-    assertPath(path);
-    let startDot = -1;
-    let startPart = 0;
-    let end = -1;
-    let matchedSlash = true;
-    // Track the state of characters (if any) we see before our first dot and
-    // after any path separator we find
-    let preDotState = 0;
-    for (let i = path.length - 1; i >= 0; --i) {
-      const code = path.charCodeAt(i);
-      if (code === CHAR_FORWARD_SLASH) {
-        // 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 === CHAR_DOT) {
-        // 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)
-    ) {
-      return "";
-    }
-    return path.slice(startDot, end);
-  },
-
-  format(pathObject: FormatInputPathObject): string {
-    if (pathObject === null || typeof pathObject !== "object") {
-      throw new TypeError(
-        `The "pathObject" argument must be of type Object. Received type ${typeof pathObject}`
-      );
-    }
-    return _format("/", pathObject);
-  },
-
-  parse(path: string): ParsedPath {
-    assertPath(path);
-
-    let ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
-    if (path.length === 0) return ret;
-    let isAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
-    let start: number;
-    if (isAbsolute) {
-      ret.root = "/";
-      start = 1;
-    } else {
-      start = 0;
-    }
-    let startDot = -1;
-    let startPart = 0;
-    let end = -1;
-    let matchedSlash = true;
-    let i = path.length - 1;
-
-    // Track the state of characters (if any) we see before our first dot and
-    // after any path separator we find
-    let preDotState = 0;
-
-    // Get non-dir info
-    for (; i >= start; --i) {
-      const code = path.charCodeAt(i);
-      if (code === CHAR_FORWARD_SLASH) {
-        // 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 === CHAR_DOT) {
-        // 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);
-    }
-
-    if (startPart > 0) ret.dir = path.slice(0, startPart - 1);
-    else if (isAbsolute) ret.dir = "/";
-
-    return ret;
-  },
-
-  sep: "/",
-  delimiter: ":",
-  win32: null,
-  posix: null
-};
-
-posix.win32 = win32.win32 = win32;
-posix.posix = win32.posix = posix;
-
-const module = isWindows ? win32 : posix;
-
-export const resolve = module.resolve;
-export const normalize = module.normalize;
-export const isAbsolute = module.isAbsolute;
-export const join = module.join;
-export const relative = module.relative;
-export const toNamespacedPath = module.toNamespacedPath;
-export const dirname = module.dirname;
-export const basename = module.basename;
-export const extname = module.extname;
-export const format = module.format;
-export const parse = module.parse;
-export const sep = module.sep;
-export const delimiter = module.delimiter;
+import * as _win32 from "./win32.ts";
+import * as _posix from "./posix.ts";
+
+import { isWindows } from "./constants.ts";
+
+const path = isWindows ? _win32 : _posix;
+
+export const win32 = _win32;
+export const posix = _posix;
+export const resolve = path.resolve;
+export const normalize = path.normalize;
+export const isAbsolute = path.isAbsolute;
+export const join = path.join;
+export const relative = path.relative;
+export const toNamespacedPath = path.toNamespacedPath;
+export const dirname = path.dirname;
+export const basename = path.basename;
+export const extname = path.extname;
+export const format = path.format;
+export const parse = path.parse;
+export const sep = path.sep;
+export const delimiter = path.delimiter;
diff --git a/fs/path/posix.ts b/fs/path/posix.ts
new file mode 100644
index 000000000..4fe0f64c0
--- /dev/null
+++ b/fs/path/posix.ts
@@ -0,0 +1,421 @@
+// Copyright the Browserify authors. MIT License.
+// Ported from https://github.com/browserify/path-browserify/
+
+const { cwd } = Deno;
+import { FormatInputPathObject, ParsedPath } from "./interface.ts";
+import { CHAR_DOT, CHAR_FORWARD_SLASH } from "./constants.ts";
+
+import {
+  assertPath,
+  normalizeString,
+  isPosixPathSeparator,
+  _format
+} from "./utils.ts";
+
+export const sep = "/";
+export const delimiter = ":";
+
+// path.resolve([from ...], to)
+export function resolve(...pathSegments: string[]): string {
+  let resolvedPath = "";
+  let resolvedAbsolute = false;
+
+  for (let i = pathSegments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
+    let path: string;
+
+    if (i >= 0) path = pathSegments[i];
+    else path = cwd();
+
+    assertPath(path);
+
+    // Skip empty entries
+    if (path.length === 0) {
+      continue;
+    }
+
+    resolvedPath = `${path}/${resolvedPath}`;
+    resolvedAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
+  }
+
+  // At this point the path should be resolved to a full absolute path, but
+  // handle relative paths to be safe (might happen when process.cwd() fails)
+
+  // Normalize the path
+  resolvedPath = normalizeString(
+    resolvedPath,
+    !resolvedAbsolute,
+    "/",
+    isPosixPathSeparator
+  );
+
+  if (resolvedAbsolute) {
+    if (resolvedPath.length > 0) return `/${resolvedPath}`;
+    else return "/";
+  } else if (resolvedPath.length > 0) return resolvedPath;
+  else return ".";
+}
+
+export function normalize(path: string): string {
+  assertPath(path);
+
+  if (path.length === 0) return ".";
+
+  const isAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
+  const trailingSeparator =
+    path.charCodeAt(path.length - 1) === CHAR_FORWARD_SLASH;
+
+  // Normalize the path
+  path = normalizeString(path, !isAbsolute, "/", isPosixPathSeparator);
+
+  if (path.length === 0 && !isAbsolute) path = ".";
+  if (path.length > 0 && trailingSeparator) path += "/";
+
+  if (isAbsolute) return `/${path}`;
+  return path;
+}
+
+export function isAbsolute(path: string): boolean {
+  assertPath(path);
+  return path.length > 0 && path.charCodeAt(0) === CHAR_FORWARD_SLASH;
+}
+
+export function join(...paths: string[]): string {
+  if (paths.length === 0) return ".";
+  let joined: string | undefined;
+  for (let i = 0, len = paths.length; i < len; ++i) {
+    let path = paths[i];
+    assertPath(path);
+    if (path.length > 0) {
+      if (!joined) joined = path;
+      else joined += `/${path}`;
+    }
+  }
+  if (!joined) return ".";
+  return normalize(joined);
+}
+
+export function relative(from: string, to: string): string {
+  assertPath(from);
+  assertPath(to);
+
+  if (from === to) return "";
+
+  from = resolve(from);
+  to = resolve(to);
+
+  if (from === to) return "";
+
+  // Trim any leading backslashes
+  let fromStart = 1;
+  let fromEnd = from.length;
+  for (; fromStart < fromEnd; ++fromStart) {
+    if (from.charCodeAt(fromStart) !== CHAR_FORWARD_SLASH) break;
+  }
+  let fromLen = fromEnd - fromStart;
+
+  // Trim any leading backslashes
+  let toStart = 1;
+  const toEnd = to.length;
+  for (; toStart < toEnd; ++toStart) {
+    if (to.charCodeAt(toStart) !== CHAR_FORWARD_SLASH) break;
+  }
+  let toLen = toEnd - toStart;
+
+  // Compare paths to find the longest common path from root
+  let length = fromLen < toLen ? fromLen : toLen;
+  let lastCommonSep = -1;
+  let i = 0;
+  for (; i <= length; ++i) {
+    if (i === length) {
+      if (toLen > length) {
+        if (to.charCodeAt(toStart + i) === CHAR_FORWARD_SLASH) {
+          // 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) === CHAR_FORWARD_SLASH) {
+          // 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;
+    }
+    let fromCode = from.charCodeAt(fromStart + i);
+    let toCode = to.charCodeAt(toStart + i);
+    if (fromCode !== toCode) break;
+    else if (fromCode === CHAR_FORWARD_SLASH) lastCommonSep = i;
+  }
+
+  let 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) === CHAR_FORWARD_SLASH) {
+      if (out.length === 0) out += "..";
+      else out += "/..";
+    }
+  }
+
+  // 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) === CHAR_FORWARD_SLASH) ++toStart;
+    return to.slice(toStart);
+  }
+}
+
+export function toNamespacedPath(path: string): string {
+  // Non-op on posix systems
+  return path;
+}
+
+export function dirname(path: string): string {
+  assertPath(path);
+  if (path.length === 0) return ".";
+  const hasRoot = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
+  let end = -1;
+  let matchedSlash = true;
+  for (let i = path.length - 1; i >= 1; --i) {
+    if (path.charCodeAt(i) === CHAR_FORWARD_SLASH) {
+      if (!matchedSlash) {
+        end = i;
+        break;
+      }
+    } else {
+      // We saw the first non-path separator
+      matchedSlash = false;
+    }
+  }
+
+  if (end === -1) return hasRoot ? "/" : ".";
+  if (hasRoot && end === 1) return "//";
+  return path.slice(0, end);
+}
+
+export function basename(path: string, ext = ""): string {
+  if (ext !== undefined && typeof ext !== "string")
+    throw new TypeError('"ext" argument must be a string');
+  assertPath(path);
+
+  let start = 0;
+  let end = -1;
+  let matchedSlash = true;
+  let i: number;
+
+  if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
+    if (ext.length === path.length && ext === path) return "";
+    let extIdx = ext.length - 1;
+    let firstNonSlashEnd = -1;
+    for (i = path.length - 1; i >= 0; --i) {
+      const code = path.charCodeAt(i);
+      if (code === CHAR_FORWARD_SLASH) {
+        // 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) === CHAR_FORWARD_SLASH) {
+        // 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);
+  }
+}
+
+export function extname(path: string): string {
+  assertPath(path);
+  let startDot = -1;
+  let startPart = 0;
+  let end = -1;
+  let matchedSlash = true;
+  // Track the state of characters (if any) we see before our first dot and
+  // after any path separator we find
+  let preDotState = 0;
+  for (let i = path.length - 1; i >= 0; --i) {
+    const code = path.charCodeAt(i);
+    if (code === CHAR_FORWARD_SLASH) {
+      // 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 === CHAR_DOT) {
+      // 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)
+  ) {
+    return "";
+  }
+  return path.slice(startDot, end);
+}
+
+export function format(pathObject: FormatInputPathObject): string {
+  if (pathObject === null || typeof pathObject !== "object") {
+    throw new TypeError(
+      `The "pathObject" argument must be of type Object. Received type ${typeof pathObject}`
+    );
+  }
+  return _format("/", pathObject);
+}
+
+export function parse(path: string): ParsedPath {
+  assertPath(path);
+
+  let ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
+  if (path.length === 0) return ret;
+  let isAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
+  let start: number;
+  if (isAbsolute) {
+    ret.root = "/";
+    start = 1;
+  } else {
+    start = 0;
+  }
+  let startDot = -1;
+  let startPart = 0;
+  let end = -1;
+  let matchedSlash = true;
+  let i = path.length - 1;
+
+  // Track the state of characters (if any) we see before our first dot and
+  // after any path separator we find
+  let preDotState = 0;
+
+  // Get non-dir info
+  for (; i >= start; --i) {
+    const code = path.charCodeAt(i);
+    if (code === CHAR_FORWARD_SLASH) {
+      // 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 === CHAR_DOT) {
+      // 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);
+  }
+
+  if (startPart > 0) ret.dir = path.slice(0, startPart - 1);
+  else if (isAbsolute) ret.dir = "/";
+
+  return ret;
+}
diff --git a/fs/path/utils.ts b/fs/path/utils.ts
new file mode 100644
index 000000000..e50cb6d3c
--- /dev/null
+++ b/fs/path/utils.ts
@@ -0,0 +1,116 @@
+// Copyright the Browserify authors. MIT License.
+// Ported from https://github.com/browserify/path-browserify/
+
+import { FormatInputPathObject } from "./interface.ts";
+import {
+  CHAR_UPPERCASE_A,
+  CHAR_LOWERCASE_A,
+  CHAR_UPPERCASE_Z,
+  CHAR_LOWERCASE_Z,
+  CHAR_DOT,
+  CHAR_FORWARD_SLASH,
+  CHAR_BACKWARD_SLASH
+} from "./constants.ts";
+
+export function assertPath(path: string): void {
+  if (typeof path !== "string") {
+    throw new TypeError(
+      `Path must be a string. Received ${JSON.stringify(path)}`
+    );
+  }
+}
+
+export function isPosixPathSeparator(code: number): boolean {
+  return code === CHAR_FORWARD_SLASH;
+}
+
+export function isPathSeparator(code: number): boolean {
+  return isPosixPathSeparator(code) || code === CHAR_BACKWARD_SLASH;
+}
+
+export function isWindowsDeviceRoot(code: number): boolean {
+  return (
+    (code >= CHAR_LOWERCASE_A && code <= CHAR_LOWERCASE_Z) ||
+    (code >= CHAR_UPPERCASE_A && code <= CHAR_UPPERCASE_Z)
+  );
+}
+
+// Resolves . and .. elements in a path with directory names
+export function normalizeString(
+  path: string,
+  allowAboveRoot: boolean,
+  separator: string,
+  isPathSeparator: (code: number) => boolean
+): string {
+  let res = "";
+  let lastSegmentLength = 0;
+  let lastSlash = -1;
+  let dots = 0;
+  let code: number;
+  for (let i = 0, len = path.length; i <= len; ++i) {
+    if (i < len) code = path.charCodeAt(i);
+    else if (isPathSeparator(code)) break;
+    else code = CHAR_FORWARD_SLASH;
+
+    if (isPathSeparator(code)) {
+      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) !== CHAR_DOT ||
+          res.charCodeAt(res.length - 2) !== CHAR_DOT
+        ) {
+          if (res.length > 2) {
+            const lastSlashIndex = res.lastIndexOf(separator);
+            if (lastSlashIndex === -1) {
+              res = "";
+              lastSegmentLength = 0;
+            } else {
+              res = res.slice(0, lastSlashIndex);
+              lastSegmentLength = res.length - 1 - res.lastIndexOf(separator);
+            }
+            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 += `${separator}..`;
+          else res = "..";
+          lastSegmentLength = 2;
+        }
+      } else {
+        if (res.length > 0) res += separator + path.slice(lastSlash + 1, i);
+        else res = path.slice(lastSlash + 1, i);
+        lastSegmentLength = i - lastSlash - 1;
+      }
+      lastSlash = i;
+      dots = 0;
+    } else if (code === CHAR_DOT && dots !== -1) {
+      ++dots;
+    } else {
+      dots = -1;
+    }
+  }
+  return res;
+}
+
+export function _format(
+  sep: string,
+  pathObject: FormatInputPathObject
+): string {
+  const dir: string | null = pathObject.dir || pathObject.root;
+  const base: string =
+    pathObject.base || (pathObject.name || "") + (pathObject.ext || "");
+  if (!dir) return base;
+  if (dir === pathObject.root) return dir + base;
+  return dir + sep + base;
+}
diff --git a/fs/path/win32.ts b/fs/path/win32.ts
new file mode 100644
index 000000000..6b906bc7b
--- /dev/null
+++ b/fs/path/win32.ts
@@ -0,0 +1,894 @@
+// Copyright the Browserify authors. MIT License.
+// Ported from https://github.com/browserify/path-browserify/
+
+const { cwd, env } = Deno;
+import { FormatInputPathObject, ParsedPath } from "./interface.ts";
+import {
+  CHAR_DOT,
+  CHAR_BACKWARD_SLASH,
+  CHAR_COLON,
+  CHAR_QUESTION_MARK
+} from "./constants.ts";
+
+import {
+  assertPath,
+  isPathSeparator,
+  isWindowsDeviceRoot,
+  normalizeString,
+  _format
+} from "./utils.ts";
+
+export const sep = "\\";
+export const delimiter = ";";
+
+export function resolve(...pathSegments: string[]): string {
+  let resolvedDevice = "";
+  let resolvedTail = "";
+  let resolvedAbsolute = false;
+
+  for (let i = pathSegments.length - 1; i >= -1; i--) {
+    let path: string;
+    if (i >= 0) {
+      path = pathSegments[i];
+    } else if (!resolvedDevice) {
+      path = cwd();
+    } else {
+      // Windows has the concept of drive-specific current working
+      // directories. If we've resolved a drive letter but not yet an
+      // absolute path, get cwd for that drive, or the process cwd if
+      // the drive cwd is not available. We're sure the device is not
+      // a UNC path at this points, because UNC paths are always absolute.
+      path = env()[`=${resolvedDevice}`] || cwd();
+
+      // Verify that a cwd was found and that it actually points
+      // to our drive. If not, default to the drive's root.
+      if (
+        path === undefined ||
+        path.slice(0, 3).toLowerCase() !== `${resolvedDevice.toLowerCase()}\\`
+      ) {
+        path = `${resolvedDevice}\\`;
+      }
+    }
+
+    assertPath(path);
+
+    const len = path.length;
+
+    // Skip empty entries
+    if (len === 0) continue;
+
+    let rootEnd = 0;
+    let device = "";
+    let isAbsolute = false;
+    const code = path.charCodeAt(0);
+
+    // Try to match a root
+    if (len > 1) {
+      if (isPathSeparator(code)) {
+        // Possible UNC root
+
+        // If we started with a separator, we know we at least have an
+        // absolute path of some kind (UNC or otherwise)
+        isAbsolute = true;
+
+        if (isPathSeparator(path.charCodeAt(1))) {
+          // Matched double path separator at beginning
+          let j = 2;
+          let last = j;
+          // Match 1 or more non-path separators
+          for (; j < len; ++j) {
+            if (isPathSeparator(path.charCodeAt(j))) break;
+          }
+          if (j < len && j !== last) {
+            const firstPart = path.slice(last, j);
+            // Matched!
+            last = j;
+            // Match 1 or more path separators
+            for (; j < len; ++j) {
+              if (!isPathSeparator(path.charCodeAt(j))) break;
+            }
+            if (j < len && j !== last) {
+              // Matched!
+              last = j;
+              // Match 1 or more non-path separators
+              for (; j < len; ++j) {
+                if (isPathSeparator(path.charCodeAt(j))) break;
+              }
+              if (j === len) {
+                // We matched a UNC root only
+                device = `\\\\${firstPart}\\${path.slice(last)}`;
+                rootEnd = j;
+              } else if (j !== last) {
+                // We matched a UNC root with leftovers
+
+                device = `\\\\${firstPart}\\${path.slice(last, j)}`;
+                rootEnd = j;
+              }
+            }
+          }
+        } else {
+          rootEnd = 1;
+        }
+      } else if (isWindowsDeviceRoot(code)) {
+        // Possible device root
+
+        if (path.charCodeAt(1) === CHAR_COLON) {
+          device = path.slice(0, 2);
+          rootEnd = 2;
+          if (len > 2) {
+            if (isPathSeparator(path.charCodeAt(2))) {
+              // Treat separator following drive name as an absolute path
+              // indicator
+              isAbsolute = true;
+              rootEnd = 3;
+            }
+          }
+        }
+      }
+    } else if (isPathSeparator(code)) {
+      // `path` contains just a path separator
+      rootEnd = 1;
+      isAbsolute = true;
+    }
+
+    if (
+      device.length > 0 &&
+      resolvedDevice.length > 0 &&
+      device.toLowerCase() !== resolvedDevice.toLowerCase()
+    ) {
+      // This path points to another device so it is not applicable
+      continue;
+    }
+
+    if (resolvedDevice.length === 0 && device.length > 0) {
+      resolvedDevice = device;
+    }
+    if (!resolvedAbsolute) {
+      resolvedTail = `${path.slice(rootEnd)}\\${resolvedTail}`;
+      resolvedAbsolute = isAbsolute;
+    }
+
+    if (resolvedAbsolute && resolvedDevice.length > 0) break;
+  }
+
+  // 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)
+
+  // Normalize the tail path
+  resolvedTail = normalizeString(
+    resolvedTail,
+    !resolvedAbsolute,
+    "\\",
+    isPathSeparator
+  );
+
+  return resolvedDevice + (resolvedAbsolute ? "\\" : "") + resolvedTail || ".";
+}
+
+export function normalize(path: string): string {
+  assertPath(path);
+  const len = path.length;
+  if (len === 0) return ".";
+  let rootEnd = 0;
+  let device: string;
+  let isAbsolute = false;
+  const code = path.charCodeAt(0);
+
+  // Try to match a root
+  if (len > 1) {
+    if (isPathSeparator(code)) {
+      // Possible UNC root
+
+      // If we started with a separator, we know we at least have an absolute
+      // path of some kind (UNC or otherwise)
+      isAbsolute = true;
+
+      if (isPathSeparator(path.charCodeAt(1))) {
+        // Matched double path separator at beginning
+        let j = 2;
+        let last = j;
+        // Match 1 or more non-path separators
+        for (; j < len; ++j) {
+          if (isPathSeparator(path.charCodeAt(j))) break;
+        }
+        if (j < len && j !== last) {
+          const firstPart = path.slice(last, j);
+          // Matched!
+          last = j;
+          // Match 1 or more path separators
+          for (; j < len; ++j) {
+            if (!isPathSeparator(path.charCodeAt(j))) break;
+          }
+          if (j < len && j !== last) {
+            // Matched!
+            last = j;
+            // Match 1 or more non-path separators
+            for (; j < len; ++j) {
+              if (isPathSeparator(path.charCodeAt(j))) break;
+            }
+            if (j === len) {
+              // We matched a UNC root only
+              // Return the normalized version of the UNC root since there
+              // is nothing left to process
+
+              return `\\\\${firstPart}\\${path.slice(last)}\\`;
+            } else if (j !== last) {
+              // We matched a UNC root with leftovers
+
+              device = `\\\\${firstPart}\\${path.slice(last, j)}`;
+              rootEnd = j;
+            }
+          }
+        }
+      } else {
+        rootEnd = 1;
+      }
+    } else if (isWindowsDeviceRoot(code)) {
+      // Possible device root
+
+      if (path.charCodeAt(1) === CHAR_COLON) {
+        device = path.slice(0, 2);
+        rootEnd = 2;
+        if (len > 2) {
+          if (isPathSeparator(path.charCodeAt(2))) {
+            // Treat separator following drive name as an absolute path
+            // indicator
+            isAbsolute = true;
+            rootEnd = 3;
+          }
+        }
+      }
+    }
+  } else if (isPathSeparator(code)) {
+    // `path` contains just a path separator, exit early to avoid unnecessary
+    // work
+    return "\\";
+  }
+
+  let tail: string;
+  if (rootEnd < len) {
+    tail = normalizeString(
+      path.slice(rootEnd),
+      !isAbsolute,
+      "\\",
+      isPathSeparator
+    );
+  } else {
+    tail = "";
+  }
+  if (tail.length === 0 && !isAbsolute) tail = ".";
+  if (tail.length > 0 && isPathSeparator(path.charCodeAt(len - 1)))
+    tail += "\\";
+  if (device === undefined) {
+    if (isAbsolute) {
+      if (tail.length > 0) return `\\${tail}`;
+      else return "\\";
+    } else if (tail.length > 0) {
+      return tail;
+    } else {
+      return "";
+    }
+  } else if (isAbsolute) {
+    if (tail.length > 0) return `${device}\\${tail}`;
+    else return `${device}\\`;
+  } else if (tail.length > 0) {
+    return device + tail;
+  } else {
+    return device;
+  }
+}
+
+export function isAbsolute(path: string): boolean {
+  assertPath(path);
+  const len = path.length;
+  if (len === 0) return false;
+
+  const code = path.charCodeAt(0);
+  if (isPathSeparator(code)) {
+    return true;
+  } else if (isWindowsDeviceRoot(code)) {
+    // Possible device root
+
+    if (len > 2 && path.charCodeAt(1) === CHAR_COLON) {
+      if (isPathSeparator(path.charCodeAt(2))) return true;
+    }
+  }
+  return false;
+}
+
+export function join(...paths: string[]): string {
+  const pathsCount = paths.length;
+  if (pathsCount === 0) return ".";
+
+  let joined: string;
+  let firstPart: string;
+  for (let i = 0; i < pathsCount; ++i) {
+    let path = paths[i];
+    assertPath(path);
+    if (path.length > 0) {
+      if (joined === undefined) joined = firstPart = path;
+      else joined += `\\${path}`;
+    }
+  }
+
+  if (joined === undefined) return ".";
+
+  // Make sure that the joined path doesn't start with two slashes, because
+  // normalize() will mistake it for an UNC path then.
+  //
+  // This step is skipped when it is very clear that the user actually
+  // intended to point at an UNC path. This is assumed when the first
+  // non-empty string arguments starts with exactly two slashes followed by
+  // at least one more non-slash character.
+  //
+  // Note that for normalize() to treat a path as an UNC path it needs to
+  // have at least 2 components, so we don't filter for that here.
+  // This means that the user can use join to construct UNC paths from
+  // a server name and a share name; for example:
+  //   path.join('//server', 'share') -> '\\\\server\\share\\')
+  let needsReplace = true;
+  let slashCount = 0;
+  if (isPathSeparator(firstPart.charCodeAt(0))) {
+    ++slashCount;
+    const firstLen = firstPart.length;
+    if (firstLen > 1) {
+      if (isPathSeparator(firstPart.charCodeAt(1))) {
+        ++slashCount;
+        if (firstLen > 2) {
+          if (isPathSeparator(firstPart.charCodeAt(2))) ++slashCount;
+          else {
+            // We matched a UNC path in the first part
+            needsReplace = false;
+          }
+        }
+      }
+    }
+  }
+  if (needsReplace) {
+    // Find any more consecutive slashes we need to replace
+    for (; slashCount < joined.length; ++slashCount) {
+      if (!isPathSeparator(joined.charCodeAt(slashCount))) break;
+    }
+
+    // Replace the slashes if needed
+    if (slashCount >= 2) joined = `\\${joined.slice(slashCount)}`;
+  }
+
+  return normalize(joined);
+}
+
+// It will solve the relative path from `from` to `to`, for instance:
+//  from = 'C:\\orandea\\test\\aaa'
+//  to = 'C:\\orandea\\impl\\bbb'
+// The output of the function should be: '..\\..\\impl\\bbb'
+export function relative(from: string, to: string): string {
+  assertPath(from);
+  assertPath(to);
+
+  if (from === to) return "";
+
+  let fromOrig = resolve(from);
+  let toOrig = resolve(to);
+
+  if (fromOrig === toOrig) return "";
+
+  from = fromOrig.toLowerCase();
+  to = toOrig.toLowerCase();
+
+  if (from === to) return "";
+
+  // Trim any leading backslashes
+  let fromStart = 0;
+  let fromEnd = from.length;
+  for (; fromStart < fromEnd; ++fromStart) {
+    if (from.charCodeAt(fromStart) !== CHAR_BACKWARD_SLASH) break;
+  }
+  // Trim trailing backslashes (applicable to UNC paths only)
+  for (; fromEnd - 1 > fromStart; --fromEnd) {
+    if (from.charCodeAt(fromEnd - 1) !== CHAR_BACKWARD_SLASH) break;
+  }
+  let fromLen = fromEnd - fromStart;
+
+  // Trim any leading backslashes
+  let toStart = 0;
+  let toEnd = to.length;
+  for (; toStart < toEnd; ++toStart) {
+    if (to.charCodeAt(toStart) !== CHAR_BACKWARD_SLASH) break;
+  }
+  // Trim trailing backslashes (applicable to UNC paths only)
+  for (; toEnd - 1 > toStart; --toEnd) {
+    if (to.charCodeAt(toEnd - 1) !== CHAR_BACKWARD_SLASH) break;
+  }
+  let toLen = toEnd - toStart;
+
+  // Compare paths to find the longest common path from root
+  let length = fromLen < toLen ? fromLen : toLen;
+  let lastCommonSep = -1;
+  let i = 0;
+  for (; i <= length; ++i) {
+    if (i === length) {
+      if (toLen > length) {
+        if (to.charCodeAt(toStart + i) === CHAR_BACKWARD_SLASH) {
+          // We get here if `from` is the exact base path for `to`.
+          // For example: from='C:\\foo\\bar'; to='C:\\foo\\bar\\baz'
+          return toOrig.slice(toStart + i + 1);
+        } else if (i === 2) {
+          // We get here if `from` is the device root.
+          // For example: from='C:\\'; to='C:\\foo'
+          return toOrig.slice(toStart + i);
+        }
+      }
+      if (fromLen > length) {
+        if (from.charCodeAt(fromStart + i) === CHAR_BACKWARD_SLASH) {
+          // We get here if `to` is the exact base path for `from`.
+          // For example: from='C:\\foo\\bar'; to='C:\\foo'
+          lastCommonSep = i;
+        } else if (i === 2) {
+          // We get here if `to` is the device root.
+          // For example: from='C:\\foo\\bar'; to='C:\\'
+          lastCommonSep = 3;
+        }
+      }
+      break;
+    }
+    let fromCode = from.charCodeAt(fromStart + i);
+    let toCode = to.charCodeAt(toStart + i);
+    if (fromCode !== toCode) break;
+    else if (fromCode === CHAR_BACKWARD_SLASH) lastCommonSep = i;
+  }
+
+  // We found a mismatch before the first common path separator was seen, so
+  // return the original `to`.
+  if (i !== length && lastCommonSep === -1) {
+    return toOrig;
+  }
+
+  let out = "";
+  if (lastCommonSep === -1) lastCommonSep = 0;
+  // 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) === CHAR_BACKWARD_SLASH) {
+      if (out.length === 0) out += "..";
+      else out += "\\..";
+    }
+  }
+
+  // Lastly, append the rest of the destination (`to`) path that comes after
+  // the common path parts
+  if (out.length > 0) return out + toOrig.slice(toStart + lastCommonSep, toEnd);
+  else {
+    toStart += lastCommonSep;
+    if (toOrig.charCodeAt(toStart) === CHAR_BACKWARD_SLASH) ++toStart;
+    return toOrig.slice(toStart, toEnd);
+  }
+}
+
+export function toNamespacedPath(path: string): string {
+  // Note: this will *probably* throw somewhere.
+  if (typeof path !== "string") return path;
+  if (path.length === 0) return "";
+
+  const resolvedPath = resolve(path);
+
+  if (resolvedPath.length >= 3) {
+    if (resolvedPath.charCodeAt(0) === CHAR_BACKWARD_SLASH) {
+      // Possible UNC root
+
+      if (resolvedPath.charCodeAt(1) === CHAR_BACKWARD_SLASH) {
+        const code = resolvedPath.charCodeAt(2);
+        if (code !== CHAR_QUESTION_MARK && code !== CHAR_DOT) {
+          // Matched non-long UNC root, convert the path to a long UNC path
+          return `\\\\?\\UNC\\${resolvedPath.slice(2)}`;
+        }
+      }
+    } else if (isWindowsDeviceRoot(resolvedPath.charCodeAt(0))) {
+      // Possible device root
+
+      if (
+        resolvedPath.charCodeAt(1) === CHAR_COLON &&
+        resolvedPath.charCodeAt(2) === CHAR_BACKWARD_SLASH
+      ) {
+        // Matched device root, convert the path to a long UNC path
+        return `\\\\?\\${resolvedPath}`;
+      }
+    }
+  }
+
+  return path;
+}
+
+export function dirname(path: string): string {
+  assertPath(path);
+  const len = path.length;
+  if (len === 0) return ".";
+  let rootEnd = -1;
+  let end = -1;
+  let matchedSlash = true;
+  let offset = 0;
+  const code = path.charCodeAt(0);
+
+  // Try to match a root
+  if (len > 1) {
+    if (isPathSeparator(code)) {
+      // Possible UNC root
+
+      rootEnd = offset = 1;
+
+      if (isPathSeparator(path.charCodeAt(1))) {
+        // Matched double path separator at beginning
+        let j = 2;
+        let last = j;
+        // Match 1 or more non-path separators
+        for (; j < len; ++j) {
+          if (isPathSeparator(path.charCodeAt(j))) break;
+        }
+        if (j < len && j !== last) {
+          // Matched!
+          last = j;
+          // Match 1 or more path separators
+          for (; j < len; ++j) {
+            if (!isPathSeparator(path.charCodeAt(j))) break;
+          }
+          if (j < len && j !== last) {
+            // Matched!
+            last = j;
+            // Match 1 or more non-path separators
+            for (; j < len; ++j) {
+              if (isPathSeparator(path.charCodeAt(j))) break;
+            }
+            if (j === len) {
+              // We matched a UNC root only
+              return path;
+            }
+            if (j !== last) {
+              // We matched a UNC root with leftovers
+
+              // Offset by 1 to include the separator after the UNC root to
+              // treat it as a "normal root" on top of a (UNC) root
+              rootEnd = offset = j + 1;
+            }
+          }
+        }
+      }
+    } else if (isWindowsDeviceRoot(code)) {
+      // Possible device root
+
+      if (path.charCodeAt(1) === CHAR_COLON) {
+        rootEnd = offset = 2;
+        if (len > 2) {
+          if (isPathSeparator(path.charCodeAt(2))) rootEnd = offset = 3;
+        }
+      }
+    }
+  } else if (isPathSeparator(code)) {
+    // `path` contains just a path separator, exit early to avoid
+    // unnecessary work
+    return path;
+  }
+
+  for (let i = len - 1; i >= offset; --i) {
+    if (isPathSeparator(path.charCodeAt(i))) {
+      if (!matchedSlash) {
+        end = i;
+        break;
+      }
+    } else {
+      // We saw the first non-path separator
+      matchedSlash = false;
+    }
+  }
+
+  if (end === -1) {
+    if (rootEnd === -1) return ".";
+    else end = rootEnd;
+  }
+  return path.slice(0, end);
+}
+
+export function basename(path: string, ext = ""): string {
+  if (ext !== undefined && typeof ext !== "string")
+    throw new TypeError('"ext" argument must be a string');
+
+  assertPath(path);
+
+  let start = 0;
+  let end = -1;
+  let matchedSlash = true;
+  let i: number;
+
+  // Check for a drive letter prefix so as not to mistake the following
+  // path separator as an extra separator at the end of the path that can be
+  // disregarded
+  if (path.length >= 2) {
+    const drive = path.charCodeAt(0);
+    if (isWindowsDeviceRoot(drive)) {
+      if (path.charCodeAt(1) === CHAR_COLON) start = 2;
+    }
+  }
+
+  if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
+    if (ext.length === path.length && ext === path) return "";
+    let extIdx = ext.length - 1;
+    let firstNonSlashEnd = -1;
+    for (i = path.length - 1; i >= start; --i) {
+      const code = path.charCodeAt(i);
+      if (isPathSeparator(code)) {
+        // 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 >= start; --i) {
+      if (isPathSeparator(path.charCodeAt(i))) {
+        // 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);
+  }
+}
+
+export function extname(path: string): string {
+  assertPath(path);
+  let start = 0;
+  let startDot = -1;
+  let startPart = 0;
+  let end = -1;
+  let matchedSlash = true;
+  // Track the state of characters (if any) we see before our first dot and
+  // after any path separator we find
+  let preDotState = 0;
+
+  // Check for a drive letter prefix so as not to mistake the following
+  // path separator as an extra separator at the end of the path that can be
+  // disregarded
+
+  if (
+    path.length >= 2 &&
+    path.charCodeAt(1) === CHAR_COLON &&
+    isWindowsDeviceRoot(path.charCodeAt(0))
+  ) {
+    start = startPart = 2;
+  }
+
+  for (let i = path.length - 1; i >= start; --i) {
+    const code = path.charCodeAt(i);
+    if (isPathSeparator(code)) {
+      // 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 === CHAR_DOT) {
+      // 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)
+  ) {
+    return "";
+  }
+  return path.slice(startDot, end);
+}
+
+export function format(pathObject: FormatInputPathObject): string {
+  if (pathObject === null || typeof pathObject !== "object") {
+    throw new TypeError(
+      `The "pathObject" argument must be of type Object. Received type ${typeof pathObject}`
+    );
+  }
+  return _format("\\", pathObject);
+}
+
+export function parse(path: string): ParsedPath {
+  assertPath(path);
+
+  let ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
+
+  const len = path.length;
+  if (len === 0) return ret;
+
+  let rootEnd = 0;
+  let code = path.charCodeAt(0);
+
+  // Try to match a root
+  if (len > 1) {
+    if (isPathSeparator(code)) {
+      // Possible UNC root
+
+      rootEnd = 1;
+      if (isPathSeparator(path.charCodeAt(1))) {
+        // Matched double path separator at beginning
+        let j = 2;
+        let last = j;
+        // Match 1 or more non-path separators
+        for (; j < len; ++j) {
+          if (isPathSeparator(path.charCodeAt(j))) break;
+        }
+        if (j < len && j !== last) {
+          // Matched!
+          last = j;
+          // Match 1 or more path separators
+          for (; j < len; ++j) {
+            if (!isPathSeparator(path.charCodeAt(j))) break;
+          }
+          if (j < len && j !== last) {
+            // Matched!
+            last = j;
+            // Match 1 or more non-path separators
+            for (; j < len; ++j) {
+              if (isPathSeparator(path.charCodeAt(j))) break;
+            }
+            if (j === len) {
+              // We matched a UNC root only
+
+              rootEnd = j;
+            } else if (j !== last) {
+              // We matched a UNC root with leftovers
+
+              rootEnd = j + 1;
+            }
+          }
+        }
+      }
+    } else if (isWindowsDeviceRoot(code)) {
+      // Possible device root
+
+      if (path.charCodeAt(1) === CHAR_COLON) {
+        rootEnd = 2;
+        if (len > 2) {
+          if (isPathSeparator(path.charCodeAt(2))) {
+            if (len === 3) {
+              // `path` contains just a drive root, exit early to avoid
+              // unnecessary work
+              ret.root = ret.dir = path;
+              return ret;
+            }
+            rootEnd = 3;
+          }
+        } else {
+          // `path` contains just a drive root, exit early to avoid
+          // unnecessary work
+          ret.root = ret.dir = path;
+          return ret;
+        }
+      }
+    }
+  } else if (isPathSeparator(code)) {
+    // `path` contains just a path separator, exit early to avoid
+    // unnecessary work
+    ret.root = ret.dir = path;
+    return ret;
+  }
+
+  if (rootEnd > 0) ret.root = path.slice(0, rootEnd);
+
+  let startDot = -1;
+  let startPart = rootEnd;
+  let end = -1;
+  let matchedSlash = true;
+  let i = path.length - 1;
+
+  // Track the state of characters (if any) we see before our first dot and
+  // after any path separator we find
+  let preDotState = 0;
+
+  // Get non-dir info
+  for (; i >= rootEnd; --i) {
+    code = path.charCodeAt(i);
+    if (isPathSeparator(code)) {
+      // 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 === CHAR_DOT) {
+      // 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) {
+      ret.base = ret.name = path.slice(startPart, end);
+    }
+  } else {
+    ret.name = path.slice(startPart, startDot);
+    ret.base = path.slice(startPart, end);
+    ret.ext = path.slice(startDot, end);
+  }
+
+  // If the directory is the root, use the entire root as the `dir` including
+  // the trailing slash if any (`C:\abc` -> `C:\`). Otherwise, strip out the
+  // trailing slash (`C:\abc\def` -> `C:\abc`).
+  if (startPart > 0 && startPart !== rootEnd) {
+    ret.dir = path.slice(0, startPart - 1);
+  } else ret.dir = ret.root;
+
+  return ret;
+}