path: added parse() and format() functions

The parse() function splits a path and returns an object
with the different elements. The format() function is the
reverse of this and adds an objects corresponding path
elements to make up a string. Fixes nodejs#6976.

doc/api/path.markdown

@@ -202,6 +202,48 @@ An example on Windows:
     // returns
     ['C:\Windows\system32', 'C:\Windows', 'C:\Program Files\nodejs\']
 
+## path.parse
+
+Returns an object from a path string.
+
+An example on *nix:
+
+    path.parse('/home/user/dir/file.txt')
+    // returns
+    {
+        root : "/",
+        dir : "/home/user/dir",
+        base : "file.txt",
+        ext : ".txt",
+        name : "file"
+    }
+
+An example on Windows:
+
+    path.parse('C:\\path\\dir\\index.html')
+    // returns
+    {
+        root : "C:\",
+        dir : "C:\path\dir",
+        base : "index.html",
+        ext : ".html",
+        name : "index"
+    }
+
+## path.format
+
+Returns a path string from an object, the opposite of `path.parse` above.
+
+    path.format({
+        root : "/",
+        dir : "/home/user/dir",
+        base : "file.txt",
+        ext : ".txt",
+        name : "file"
+    })
+    // returns
+    '/home/user/dir/file.txt'
+
 ## path.posix
 
 Provide access to aforementioned `path` methods but always interact in a posix

lib/path.js

@@ -54,7 +54,6 @@ function normalizeArray(parts, allowAboveRoot) {
   return parts;
 }
 
-
 // Regex to split a windows path into three parts: [*, device, slash,
 // tail] windows-only
 var splitDeviceRe =
@@ -364,6 +363,30 @@ win32.extname = function(path) {
 };
 
 
+win32.format = function(object) {
+  var root = object.root || '';
+  var dir = object.dir;
+  var base = object.base || '';
+  if (dir.slice(dir.length - 1, dir.length) === win32.sep) {
+    return dir + base;
+  } else {
+    return dir + this.sep + base;
+  }
+};
+
+
+win32.parse = function(string) {
+  var allParts = win32.splitPath(string);
+  return {
+    root: allParts[0],
+    dir: allParts[0] + allParts[1].slice(0, allParts[1].length - 1),
+    base: allParts[2],
+    ext: allParts[3],
+    name: allParts[2].slice(0, allParts[2].length - allParts[3].length)
+  };
+};
+
+
 win32.sep = '\\';
 win32.delimiter = ';';
 
@@ -545,6 +568,30 @@ posix.extname = function(path) {
 };
 
 
+posix.format = function(object) {
+  var root = object.root || '';
+  var sep = posix.sep;
+  if (root.indexOf(':') > -1) {
+    sep = '\\';
+  }
+  var dir = object.dir + sep;
+  var base = object.base || '';
+  return dir + base;
+};
+
+
+posix.parse = function(string) {
+  var allParts = posix.splitPath(string);
+  return {
+    root: allParts[0],
+    dir: allParts[0] + allParts[1].slice(0, allParts[1].length - 1),
+    base: allParts[2],
+    ext: allParts[3],
+    name: allParts[2].slice(0, allParts[2].length - allParts[3].length)
+  };
+};
+
+
 posix.sep = '/';
 posix.delimiter = ':';
 

test/simple/test-path-parse-format.js

@@ -0,0 +1,64 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var assert = require('assert');
+var path = require('path');
+
+var winPaths = [
+  'C:\\path\\dir\\index.html',
+  'C:\\another_path\\DIR\\1\\2\\33\\index',
+  'another_path\\DIR with spaces\\1\\2\\33\\index',
+
+  // unc
+  '\\\\server\\share\\file_path',
+  '\\\\server two\\shared folder\\file path.zip',
+  '\\\\teela\\admin$\\system32'
+
+];
+
+var unixPaths = [
+  '/home/user/dir/file.txt',
+  '/home/user/a dir/another File.zip',
+  '/home/user/a dir//another&File.',
+  '/home/user/a$$$dir//another File.zip',
+  'user/dir/another File.zip'
+];
+
+check(path.win32, winPaths);
+check(path.posix, unixPaths);
+
+function check(path, paths) {
+  paths.forEach(function(element, index, array) {
+    var count = index + 1;
+    console.log(count + ': `' + element + '`');
+    var output = path.parse(element);
+    var keys = Object.keys(output);
+    var values = [];
+    for (var i = 0; i < Object.keys(output).length; i++) {
+      values.push(output[keys[i]]);
+    }
+
+    assert.strictEqual(path.format(path.parse(element)), element);
+    assert.strictEqual(path.parse(element).dir, path.dirname(element));
+    assert.strictEqual(path.parse(element).base, path.basename(element));
+    assert.strictEqual(path.parse(element).ext, path.extname(element));
+  })
+}