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doc: general improvements to path.md copy

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PR-URL: https://github.com/nodejs/node/pull/7122
Reviewed-By: Brian White <mscdex@mscdex.net>
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James M Snell 2016-06-02 17:43:26 -07:00
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doc/api/path.md
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@ -2,37 +2,93 @@
Stability: 2 - Stable Stability: 2 - Stable
This module contains utilities for handling and transforming file The `path` module provides utilities for working with file and directory paths.
paths. The file system is not consulted to check whether paths are valid. It can be accessed using:
Use `require('path')` to use this module. The following methods are provided: ```js
const path = require('path');
```
## Windows vs. POSIX
The default operation of the `path` module varies based on the operating system
on which a Node.js application is running. Specifically, when running on a
Windows operating system, the `path` module will assume that Windows-style
paths are being used.
For example, using the `path.basename()` function with the Windows file path
`C:\temp\myfile.html`, will yield different results when running on POSIX than
when run on Windows:
On POSIX:
```js
path.basename('C:\\temp\\myfile.html');
// returns 'C:\temp\myfile.html'
```
On Windows:
```js
path.basename('C:\\temp\\myfile.html');
// returns 'myfile.html'
```
To achieve consistent results when working with Windows file paths on any
operating system, use [`path.win32`][]:
On POSIX and Windows:
```js
path.win32.basename('C:\\temp\\myfile.html');
// returns 'myfile.html'
```
To achieve consistent results when working with POSIX file paths on any
operating system, use [`path.posix`][]:
On POSIX and Windows:
```js
path.posix.basename('/tmp/myfile.html');
// returns 'myfile.html'
```
## path.basename(path[, ext]) ## path.basename(path[, ext])
<!-- YAML <!-- YAML
added: v0.1.25 added: v0.1.25
--> -->
Return the last portion of a path, similar to the Unix `basename` command. * `path` {String}
`path` must be a string. `ext`, if given, must also be a string. * `ext` {String} An optional file extension
Examples: The `path.basename()` methods returns the last portion of a `path`, similar to
the Unix `basename` command.
For example:
```js ```js
path.basename('/foo/bar/baz/asdf/quux.html') path.basename('/foo/bar/baz/asdf/quux.html')
// returns 'quux.html' // returns 'quux.html'
path.basename('/foo/bar/baz/asdf/quux.html', '.html') path.basename('/foo/bar/baz/asdf/quux.html', '.html')
// returns 'quux' // returns 'quux'
``` ```
A [`TypeError`][] is thrown if `path` is not a string or if `ext` is given
and is not a string.
## path.delimiter ## path.delimiter
<!-- YAML <!-- YAML
added: v0.9.3 added: v0.9.3
--> -->
The platform-specific path delimiter, `;` or `':'`. Provides the platform-specific path delimiter:
An example on \*nix: * `;` for Windows
* `:` for POSIX
For example, on POSIX:
```js ```js
console.log(process.env.PATH) console.log(process.env.PATH)
@ -42,7 +98,7 @@ process.env.PATH.split(path.delimiter)
// returns ['/usr/bin', '/bin', '/usr/sbin', '/sbin', '/usr/local/bin'] // returns ['/usr/bin', '/bin', '/usr/sbin', '/sbin', '/usr/local/bin']
``` ```
An example on Windows: On Windows:
```js ```js
console.log(process.env.PATH) console.log(process.env.PATH)
@ -57,27 +113,34 @@ process.env.PATH.split(path.delimiter)
added: v0.1.16 added: v0.1.16
--> -->
Return the directory name of a path, similar to the Unix `dirname` command. * `path` {String}
`path` must be a string.
Example: The `path.dirname()` method returns the directory name of a `path`, similar to
the Unix `dirname` command.
For example:
```js ```js
path.dirname('/foo/bar/baz/asdf/quux') path.dirname('/foo/bar/baz/asdf/quux')
// returns '/foo/bar/baz/asdf' // returns '/foo/bar/baz/asdf'
``` ```
A [`TypeError`][] is thrown if `path` is not a string.
## path.extname(path) ## path.extname(path)
<!-- YAML <!-- YAML
added: v0.1.25 added: v0.1.25
--> -->
Return the extension of the path, from the last '.' to end of string * `path` {String}
in the last portion of the path. If there is no '.' in the last portion
of the path or the first character of it is '.', then it returns
an empty string. `path` must be a string.
Examples: The `path.extname()` method returns the extension of the `path`, from the last
occurance of the `.` (period) character to end of string in the last portion of
the `path`. If there is no `.` in the last portion of the `path`, or if the
first character of the basename of `path` (see `path.basename()`) is `.`, then
an empty string is returned.
For example:
```js ```js
path.extname('index.html') path.extname('index.html')
@ -96,66 +159,73 @@ path.extname('.index')
// returns '' // returns ''
``` ```
A [`TypeError`][] is thrown if `path` is not a string.
## path.format(pathObject) ## path.format(pathObject)
<!-- YAML <!-- YAML
added: v0.11.15 added: v0.11.15
--> -->
Returns a path string from an object. This is the opposite of [`path.parse`][]. * `pathObject` {Object}
* `dir` {String}
* `root` {String}
* `base` {String}
* `name` {String}
* `ext` {String}
If `pathObject` has `dir` and `base` properties, the returned string will The `path.format()` method returns a path string from an object. This is the
be a concatenation of the `dir` property, the platform-dependent path separator, opposite of [`path.parse()`][].
and the `base` property.
If the `dir` property is not supplied, the `root` property will be used as the The following process is used when constructing the path string:
`dir` property. However, it will be assumed that the `root` property already
ends with the platform-dependent path separator. In this case, the returned
string will be the concatenation of the `root` property and the `base` property.
If both the `dir` and the `root` properties are not supplied, then the returned * `output` is set to an empty string.
string will be the contents of the `base` property. * If `pathObject.dir` is specified, `pathObject.dir` is appended to `output`
followed by the value of `path.sep`;
* Otherwise, if `pathObject.root` is specified, `pathObject.root` is appended
to `output`.
* If `pathObject.base` is specified, `pathObject.base` is appended to `output`;
* Otherwise:
* If `pathObject.name` is specified, `pathObject.name` is appended to `output`
* If `pathObject.ext` is specified, `pathObject.ext` is appended to `output`.
* Return `output`
If the `base` property is not supplied, a concatenation of the `name` property For example, on POSIX:
and the `ext` property will be used as the `base` property.
Examples:
Some Posix system examples:
```js ```js
// If `dir` and `base` are provided, `dir` + platform separator + `base` // If `dir` and `base` are provided,
// `${dir}${path.sep}${base}`
// will be returned. // will be returned.
path.format({ path.format({
dir: '/home/user/dir', dir: '/home/user/dir',
base: 'file.txt' base: 'file.txt'
}); });
// returns '/home/user/dir/file.txt' // returns '/home/user/dir/file.txt'
// `root` will be used if `dir` is not specified. // `root` will be used if `dir` is not specified.
// `name` + `ext` will be used if `base` is not specified.
// If only `root` is provided or `dir` is equal to `root` then the // If only `root` is provided or `dir` is equal to `root` then the
// platform separator will not be included. // platform separator will not be included.
path.format({ path.format({
root: '/', root: '/',
base: 'file.txt' base: 'file.txt'
}); });
// returns '/file.txt' // returns '/file.txt'
// `name` + `ext` will be used if `base` is not specified.
path.format({ path.format({
dir: '/', root: '/',
root: '/', name: 'file',
name: 'file', ext: '.txt'
ext: '.txt'
}); });
// returns '/file.txt' // returns '/file.txt'
// `base` will be returned if `dir` or `root` are not provided. // `base` will be returned if `dir` or `root` are not provided.
path.format({ path.format({
base: 'file.txt' base: 'file.txt'
}); });
// returns 'file.txt' // returns 'file.txt'
``` ```
An example on Windows:
On Windows:
```js ```js
path.format({ path.format({
@ -173,11 +243,13 @@ path.format({
added: v0.11.2 added: v0.11.2
--> -->
Determines whether `path` is an absolute path. An absolute path will always * `path` {String}
resolve to the same location, regardless of the working directory. `path` must
be a string.
Examples on \*nix: The `path.isAbsolute()` method determines if `path` is an absolute path.
If the given `path` is a zero-length string, `false` will be returned.
For example on POSIX:
```js ```js
path.isAbsolute('/foo/bar') // true path.isAbsolute('/foo/bar') // true
@ -186,7 +258,7 @@ path.isAbsolute('qux/') // false
path.isAbsolute('.') // false path.isAbsolute('.') // false
``` ```
Examples on Windows: On Windows:
```js ```js
path.isAbsolute('//server') // true path.isAbsolute('//server') // true
@ -195,66 +267,86 @@ path.isAbsolute('bar\\baz') // false
path.isAbsolute('.') // false path.isAbsolute('.') // false
``` ```
*Note:* If the path string passed as parameter is a zero-length string, unlike A [`TypeError`][] is thrown if `path` is not a string.
other path module functions, it will be used as-is and `false` will be
returned.
## path.join([path1][, path2][, ...]) ## path.join([path[, ...]])
<!-- YAML <!-- YAML
added: v0.1.16 added: v0.1.16
--> -->
Join all arguments together and normalize the resulting path. * `[path[, ...]]` {String} A sequence of path segments
All arguments must be strings. In v0.8, non-string arguments were The `path.join()` method join all given `path` segments together using the
silently ignored. In v0.10 and up, an exception is thrown. platform specific separator as a delimiter, then normalizes the resulting path.
Examples: Zero-length `path` segments are ignored. If the joined path string is a
zero-length string then `'.'` will be returned, representing the current
working directory.
For example:
```js ```js
path.join('/foo', 'bar', 'baz/asdf', 'quux', '..') path.join('/foo', 'bar', 'baz/asdf', 'quux', '..')
// returns '/foo/bar/baz/asdf' // returns '/foo/bar/baz/asdf'
path.join('foo', {}, 'bar') path.join('foo', {}, 'bar')
// throws exception // throws TypeError: Arguments to path.join must be strings
TypeError: Arguments to path.join must be strings
``` ```
*Note:* If the arguments to `join` have zero-length strings, unlike other path A [`TypeError`][] is thrown if any of the path segments is not a string.
module functions, they will be ignored. If the joined path string is a
zero-length string then `'.'` will be returned, which represents the
current working directory.
## path.normalize(path) ## path.normalize(path)
<!-- YAML <!-- YAML
added: v0.1.23 added: v0.1.23
--> -->
Normalize a path, taking care of `'..'` and `'.'` parts. `path` must be a * `path` {String}
string.
When multiple slashes are found, they're replaced by a single one; The `path.normalize()` method normalizes the given `path`, resolving `'..'` and
when the path contains a trailing slash, it is preserved. `'.'` segments.
On Windows backslashes are used.
Example: When multiple, sequential path segment separation characters are found (e.g.
`/` on POSIX and `\` on Windows), they are replaced by a single instance of the
platform specific path segment separator. Trailing separators are preserved.
If the `path` is a zero-length string, `'.'` is returned, representing the
current working directory.
For example on POSIX:
```js ```js
path.normalize('/foo/bar//baz/asdf/quux/..') path.normalize('/foo/bar//baz/asdf/quux/..')
// returns '/foo/bar/baz/asdf' // returns '/foo/bar/baz/asdf'
``` ```
*Note:* If the path string passed as argument is a zero-length string then `'.'` On Windows:
will be returned, which represents the current working directory.
```js
path.normalize('C:\\temp\\\\foo\\bar\\..\\');
// returns 'C:\\temp\\foo\\'
```
A [`TypeError`][] is thrown if `path` is not a string.
## path.parse(path) ## path.parse(path)
<!-- YAML <!-- YAML
added: v0.11.15 added: v0.11.15
--> -->
Returns an object from a path. `path` must be a string. * `path` {String}
An example on \*nix: The `path.parse()` method returns an object whose properties represent
significant elements of the `path`.
The returned object will have the following properties:
* `root` {String}
* `dir` {String}
* `base` {String}
* `ext` {String}
* `name` {String}
For example on POSIX:
```js ```js
path.parse('/home/user/dir/file.txt') path.parse('/home/user/dir/file.txt')
@ -268,91 +360,108 @@ path.parse('/home/user/dir/file.txt')
// } // }
``` ```
An example on Windows: ```text
┌─────────────────────┬────────────┐
│ dir │ base │
├──────┬ ├──────┬─────┤
│ root │ │ name │ ext │
" / home/user/dir / file .txt "
└──────┴──────────────┴──────┴─────┘
(all spaces in the "" line should be ignored -- they're purely for formatting)
```
On Windows:
```js ```js
path.parse('C:\\path\\dir\\index.html') path.parse('C:\\path\\dir\\file.txt')
// returns // returns
// { // {
// root : "C:\\", // root : "C:\\",
// dir : "C:\\path\\dir", // dir : "C:\\path\\dir",
// base : "index.html", // base : "file.txt",
// ext : ".html", // ext : ".txt",
// name : "index" // name : "file"
// } // }
``` ```
```text
┌─────────────────────┬────────────┐
│ dir │ base │
├──────┬ ├──────┬─────┤
│ root │ │ name │ ext │
" C:\ path\dir \ file .txt "
└──────┴──────────────┴──────┴─────┘
(all spaces in the "" line should be ignored -- they're purely for formatting)
```
A [`TypeError`][] is thrown if `path` is not a string.
## path.posix ## path.posix
<!-- YAML <!-- YAML
added: v0.11.15 added: v0.11.15
--> -->
Provide access to aforementioned `path` methods but always interact in a posix The `path.posix` property provides access to POSIX specific implementations
compatible way. of the `path` methods.
## path.relative(from, to) ## path.relative(from, to)
<!-- YAML <!-- YAML
added: v0.5.0 added: v0.5.0
--> -->
Solve the relative path from `from` to `to`. `from` and `to` must be strings. * `from` {String}
* `to` {String}
At times we have two absolute paths, and we need to derive the relative The `path.relative()` method returns the relative path from `from` to `to`.
path from one to the other. This is actually the reverse transform of If `from` and `to` each resolve to the same path (after calling `path.resolve()`
`path.resolve`, which means we see that: on each), a zero-length string is returned.
If a zero-length string is passed as `from` or `to`, the current working
directory will be used instead of the zero-length strings.
For example on POSIX:
```js ```js
path.resolve(from, path.relative(from, to)) == path.resolve(to)
```
Examples:
```js
path.relative('C:\\orandea\\test\\aaa', 'C:\\orandea\\impl\\bbb')
// returns '..\\..\\impl\\bbb'
path.relative('/data/orandea/test/aaa', '/data/orandea/impl/bbb') path.relative('/data/orandea/test/aaa', '/data/orandea/impl/bbb')
// returns '../../impl/bbb' // returns '../../impl/bbb'
``` ```
*Note:* If the arguments to `relative` have zero-length strings then the current On Windows:
working directory will be used instead of the zero-length strings. If
both the paths are the same then a zero-length string will be returned.
## path.resolve([from ...], to) ```js
path.relative('C:\\orandea\\test\\aaa', 'C:\\orandea\\impl\\bbb')
// returns '..\\..\\impl\\bbb'
```
A [`TypeError`][] is thrown if neither `from` nor `to` is a string.
## path.resolve([path[, ...]])
<!-- YAML <!-- YAML
added: v0.3.4 added: v0.3.4
--> -->
Resolves `to` to an absolute path. All arguments must be strings. * `[path[, ...]]` {String} A sequence of paths or path segments
If `to` isn't already absolute `from` arguments are prepended in right to left The `path.resolve()` method resolves a sequence of paths or path segments into
order, until an absolute path is found. If after using all `from` paths still an absolute path.
no absolute path is found, the current working directory is used as well. The
resulting path is normalized, and trailing slashes are removed unless the path
gets resolved to the root directory. Empty string `from` arguments are
ignored.
Another way to think of it is as a sequence of `cd` commands in a shell. The given sequence of paths is processed from right to left, with each
subsequent `path` prepended until an absolute path is constructed.
For instance, given the sequence of path segments: `/foo`, `/bar`, `baz`,
calling `path.resolve('/foo', '/bar', 'baz')` would return `/bar/baz`.
```js If after processing all given `path` segments an absolute path has not yet
path.resolve('foo/bar', '/tmp/file/', '..', 'a/../subfile') been generated, the current working directory is used.
```
Is similar to: The resulting path is normalized and trailing slashes are removed unless the
path is resolved to the root directory.
``` Zero-length `path` segments are ignored.
cd foo/bar
cd /tmp/file/
cd ..
cd a/../subfile
pwd
```
The difference is that the different paths don't need to exist and may also be If no `path` segments are passed, `path.resolve()` will return the absolute path
files. of the current working directory.
Examples: For example:
```js ```js
path.resolve('/foo/bar', './baz') path.resolve('/foo/bar', './baz')
@ -362,25 +471,30 @@ path.resolve('/foo/bar', '/tmp/file/')
// returns '/tmp/file' // returns '/tmp/file'
path.resolve('wwwroot', 'static_files/png/', '../gif/image.gif') path.resolve('wwwroot', 'static_files/png/', '../gif/image.gif')
// if currently in /home/myself/node, it returns // if the current working directory is /home/myself/node,
// '/home/myself/node/wwwroot/static_files/gif/image.gif' // this returns '/home/myself/node/wwwroot/static_files/gif/image.gif'
``` ```
A [`TypeError`][] is thrown if any of the arguments is not a string.
## path.sep ## path.sep
<!-- YAML <!-- YAML
added: v0.7.9 added: v0.7.9
--> -->
The platform-specific file separator. `'\\'` or `'/'`. Provides the platform-specific path segment separator:
An example on \*nix: * `\` on Windows
* `/` on POSIX
For example on POSIX:
```js ```js
'foo/bar/baz'.split(path.sep) 'foo/bar/baz'.split(path.sep)
// returns ['foo', 'bar', 'baz'] // returns ['foo', 'bar', 'baz']
``` ```
An example on Windows: On Windows:
```js ```js
'foo\\bar\\baz'.split(path.sep) 'foo\\bar\\baz'.split(path.sep)
@ -392,7 +506,10 @@ An example on Windows:
added: v0.11.15 added: v0.11.15
--> -->
Provide access to aforementioned `path` methods but always interact in a win32 The `path.win32` property provides access to Windows-specific implementations
compatible way. of the `path` methods.
[`path.parse`]: #path_path_parse_path [`path.posix`]: #path_path_posix
[`path.win32`]: #path_path_win32
[`path.parse()`]: #path_path_parse_path
[`TypeError`]: errors.html#errors_class_typeerror