RingoJS

Module fs

This module provides a file system API for the manipulation of paths, directories, files, links, and the construction of input and output streams. It follows the CommonJS Filesystem/A proposal.

Example

// Writes a simple text file
const fs = require('fs');
if (!fs.exists('test.txt')) {
  const textStream = fs.open('test.txt', {
    write: true,
    binary: false
  });
  try {
    textStream.write('Hello World!');
    textStream.flush();
  } finally {
    textStream.close();
  }
  console.log('Wrote test.txt');
} else {
  console.error('test.txt already exists.');
}

Functions

Class Path

Instance Methods

Instance Properties

Path ()

Path constructor. Path is a chainable shorthand for working with paths.

Path.prototype. constructor

Path.prototype. from (target)

Return the relative path from the given source path to this path. Equivalent to fs.Path(fs.relative(source, this)).

Parameters

String target

Path.prototype. join ()

Join a list of paths to this path.

Path.prototype. listPaths ()

Return the names of all files in this path, in lexically sorted order and wrapped in Path objects.

Path.prototype. resolve ()

Resolve against this path.

Path.prototype. to (target)

Return the relative path from this path to the given target path. Equivalent to fs.Path(fs.relative(this, target)).

Parameters

String target

Path.prototype. toString ()

Path.prototype. valueOf ()

This is a non-standard extension, not part of CommonJS Filesystem/A.

absolute (path)

Make the given path absolute by resolving it against the current working directory.

Example

>> fs.absolute('foo/bar/test.txt');
'/Users/username/Desktop/working-directory/foo/bar/test.txt'

Parameters

String path

the path to resolve

Returns

String

the absolute path

base (path, ext)

Return the basename of the given path. That is the path with any leading directory components removed. If specified, also remove a trailing extension.

Example

>> fs.base('/a/b/c/foosomeext', 'someext');
'foo'

Parameters

String path

the full path
String ext

an optional extension to remove

Returns

String

the basename

canonical (path)

Returns the canonical path to a given abstract path. Canonical paths are both absolute and intrinsic, such that all paths that refer to a given file (whether it exists or not) have the same corresponding canonical path.

Parameters

String path

a file path

Returns

String

the canonical path

changeGroup (path, group)

Changes the group of the specified file.

Parameters

String path
String group

group name string

changeOwner (path, owner)

Changes the owner of the specified file.

Parameters

String path
String owner

the user name string

changePermissions (path, permissions)

Changes the permissions of the specified file.

Parameters

String path
Number|String|java.util.Set<PosixFilePermission> permissions

the POSIX permissions

copy (from, to)

Read data from one file and write it into another using binary mode. Replaces an existing file if it exists.

Example

// Copies file from a temporary upload directory into /var/www
fs.copy('/tmp/uploads/fileA.txt', '/var/www/fileA.txt');

Parameters

String from

original file
String to

copy to create

copyTree (from, to)

Copy files from a source path to a target path. Files of the below the source path are copied to the corresponding locations relative to the target path, symbolic links to directories are copied but not traversed into.

Example

Before:
└── foo
    ├── bar
    │   └── example.m4a
    └── baz

// Copy foo
fs.copyTree('./foo', './foo2');

After:
├── foo
│   ├── bar
│   │   └── example.m4a
│   └── baz
└── foo2
    ├── bar
    │   └── example.m4a
    └── baz

Parameters

String from

the original tree
String to

the destination for the copy

directory (path)

Return the dirname of the given path. That is the path with any trailing non-directory component removed.

Example

>> fs.directory('/Users/username/Desktop/example/test.txt');
'/Users/username/Desktop/example'

Parameters

String path

Returns

String

the parent directory path

exists (path)

Return true if the file denoted by path exists, false otherwise.

Parameters

String path

the file path.

extension (path)

Return the extension of a given path. That is everything after the last dot in the basename of the given path, including the last dot. Returns an empty string if no valid extension exists.

Example

>> fs.extension('test.txt');
'.txt'

Parameters

String path

Returns

String

the file's extension

getAttributes (path)

Returns basic attributes associated with a file in a file system.

Parameters

String path

Returns

Object

An Object with properties {creationTime, isDirectory, isOther, isRegularFile, isSymbolicLink, lastAccessTime, lastModifiedTime, size}

group (path)

Returns the group name for the given file.

Parameters

String path

Returns

String

the group's name, or null if not possible to determine

hardLink (existing, link)

Creates a hard link at the target path that refers to the source path. The concrete implementation depends on the file system and the operating system.

Parameters

String existing

path to an existing file, therefore the target of the link
String link

the link to create pointing to an existing path

Returns

String

the path to the link

isAbsolute (path)

Check whether the given pathname is absolute. This is a non-standard extension, not part of CommonJS Filesystem/A.

Example

>> fs.isAbsolute('../../');
false
>> fs.isAbsolute('/Users/username/Desktop/example.txt');
true

Parameters

String path

the path to check

Returns

Boolean

true if path is absolute, false if not

isDirectory (path)

Returns true if the file specified by path exists and is a directory.

Parameters

String path

the file path

Returns

Boolean

whether the file exists and is a directory

isFile (path)

Returns true if the file specified by path exists and is a regular file.

Parameters

String path

the file path

Returns

Boolean

whether the file exists and is a file

isLink (path)

Return true if target file is a symbolic link, false otherwise.

Parameters

String path

the file path

Returns

Boolean

true if the given file exists and is a symbolic link

isReadable (path)

Returns true if the file specified by path exists and can be opened for reading.

Parameters

String path

the file path

Returns

Boolean

whether the file exists and is readable

isRelative (path)

Check whether the given pathname is relative (i.e. not absolute). This is a non-standard extension, not part of CommonJS Filesystem/A.

Parameters

String path

the path to check

Returns

Boolean

true if path is relative, false if not

isWritable (path)

Returns true if the file specified by path exists and can be opened for writing.

Parameters

String path

the file path

Returns

Boolean

whether the file exists and is writable

iterate (path)

Returns a Rhino-specific generator that produces the file names of a directory. There is no guarantee that the produced strings are in any specific order.

Example

// Iterates over the current working directory
for (let name of fs.iterate(".")) {
  console.log(name);
}

Parameters

String path

a directory path

join ()

Join a list of path elements using the local file system's path separator. Empty path elements (null, undefined and empty strings) will be skipped. All non-string path elements will be converted to strings. The result is not normalized, so join("..", "foo") returns "../foo".

Example

// build path to the config.json file
const fullPath = fs.join(configDir, "config.json");

Returns

String

the joined path

lastModified (path)

Returns the time a file was last modified as a Date object.

Parameters

String path

the file path

Returns

Date

the date the file was last modified

list (path)

Returns an array of strings naming the files and directories in the given directory. There is no guarantee that the strings are in any specific order.

Example

const names = fs.list('/usr/local/');
names.forEach(function(name) {
  const fullPath = fs.join(dir, name);
  if (fs.isFile(fullPath)) {
    // do something with the file
  }
});

Parameters

String path

the directory path

Returns

Array

an array of strings with the files, directories, or symbolic links

listDirectoryTree (path)

Return an array with all directories below (and including) the given path, as discovered by depth-first traversal. Entries are in lexically sorted order within directories. Symbolic links to directories are not traversed into.

Example

// File system tree of the current working directory:
.
└── foo
    └── bar
        └── baz

fs.listDirectoryTree('.');
// returned array:
[ '', 'foo', 'foo/bar', 'foo/bar/baz' ]

Parameters

String path

the path to discover

Returns

Array

array of strings with all directories lexically sorted

listTree (path)

Return an array with all paths (files, directories, etc.) below (and including) the given path, as discovered by depth-first traversal. Entries are in lexically sorted order within directories. Symbolic links to directories are returned but not traversed into.

Example

// File system tree of the current working directory:
.
├── foo
│   └── bar
│       └── baz
├── musicfile.m4a
└── test.txt

fs.listTree('.');
// returned array:
['', 'foo', 'foo/bar', 'foo/bar/baz', 'musicfile.m4a', 'test.txt']

Parameters

String path

the path to list

Returns

Array

array of strings with all discovered paths

makeDirectory (path, permissions)

Create a single directory specified by path. If the directory cannot be created for any reason an error is thrown. This includes if the parent directories of path are not present. If a permissions argument is passed to this function it is used to create a Permissions instance which is applied to the given path during directory creation.

Parameters

String path

the file path
Number|String|java.util.Set<PosixFilePermission> permissions

optional the POSIX permissions

makeTree (path)

Create the directory specified by path including any missing parent directories.

Example

Before:
└── foo

fs.makeTree('foo/bar/baz/');

After:
└── foo
   └── bar
      └── baz

Parameters

String path

the path of the tree to create

move (source, target)

Move a file from source to target. If target already exists, it is replaced by the source file.

Example

// Moves file from a temporary upload directory into /var/www
fs.move('/tmp/uploads/fileA.txt', '/var/www/fileA.txt');

Parameters

String source

the source path
String target

the target path

Throws

Error

normal (path)

Normalize a path by removing '.' and simplifying '..' components, wherever possible.

Example

>> fs.normal('../redundant/../foo/./bar.txt');
'../foo/bar.txt'

Parameters

String path

Returns

String

the normalized path

open (path, options)

Open the file corresponding to path for reading or writing, depending on the options argument. Returns a binary stream or a text stream.

The options argument may contain the following properties:

  • read (boolean) open the file in read-only mode.
  • write (boolean) open the file in write mode starting at the beginning of the file.
  • append (boolean) open the file in write mode starting at the end of the file.
  • binary (boolean) open the file in binary mode.
  • charset (string) open the file in text mode using the given encoding. Defaults to UTF-8.

Instead of an options object, a string with the following modes can be provided:

  • r (string) equivalent to read-only
  • w (string) equivalent to write
  • a (string) equivalent to append
  • b (string) equivalent to binary

So an options object { read: true, binary: true } and the mode string 'rb' are functionally equivalent. Note: The options canonical and exclusive proposed by CommonJS are not supported.

Example

// Opens a m4a file in binary mode
const m4aStream = fs.open('music.m4a', {
   binary: true,
   read: true
});

// The equivalent call with options as string
const m4aStream = fs.open('music.m4a', 'br');

// Opens a text file
const textStream = fs.open('example.txt', { read: true });

// The equivalent call with options as string
const textStream = fs.open('example.txt', 'r');

Parameters

String path

the file path
Object|String options

options as object properties or as mode string

Returns

Stream|TextStream

a Stream object in binary mode, otherwise a TextStream

openRaw (path, options)

Opens the file corresponding to path for reading or writing in binary mode. The options argument may contain the following properties:

  • read (boolean) open the file in read-only mode. (default)
  • write (boolean) open the file in write mode starting at the beginning of the file.
  • append (boolean) open the file in write mode starting at the end of the file.

Parameters

String path

the file path
Object options

options

Returns

Stream

See

open

owner (path)

Returns the username of the owner of the given file.

Parameters

String path

Returns

String

the username of the owner, or null if not possible to determine

path ()

A shorthand for creating a new Path without the new keyword.

permissions (path)

Returns the POSIX file permissions for the given path, if the filesystem supports POSIX.

Parameters

String path

Returns

PosixFilePermission the POSIX permissions for the given path

read (path, options)

Read the content of the file corresponding to path. Returns a String or ByteString object depending on the options argument. This function supports the same options as open().

Parameters

String path

the file path
Object options

optional options

Returns

String|Binary

the content of the file

readLink (path)

Returns the immediate target of the symbolic link at the given path.

Parameters

String path

a file path

relative (source, target)

Establish the relative path that links source to target by strictly traversing up ('..') to find a common ancestor of both paths. If the target is omitted, returns the path to the source from the current working directory.

Example

>> fs.relative('foo/bar/', 'foo/baz/');
'../baz/'
>> fs.relative('foo/bar/', 'foo/bar/baz/');
'baz/'

Parameters

String source
String target

Returns

String

the path needed to change from source to target

remove (path)

Remove a file at the given path. Throws an error if path is not a file or a symbolic link to a file.

Parameters

String path

the path of the file to remove.

Throws

Error if path is not a file or could not be removed.

removeDirectory (path)

Remove a file or directory identified by path. Throws an error if path is a directory and not empty.

Parameters

String path

the directory path

Throws

Error if the file or directory could not be removed.

removeTree (path)

Remove the element pointed to by the given path. If path points to a directory, all members of the directory are removed recursively.

Example

// File system tree of the current working directory:
├── foo
│   └── bar
│       └── baz
├── musicfile.m4a
└── test.txt

fs.removeTree('foo');

After:
├── musicfile.m4a
└── test.txt

Parameters

String path

the element to delete recursively

resolve (paths...)

Join a list of paths by starting at an empty location and iteratively "walking" to each path given. Correctly takes into account both relative and absolute paths.

Example

>> fs.resolve('../.././foo/file.txt', 'bar/baz/', 'test.txt');
'../../foo/bar/baz/test.txt'

Parameters

String... paths...

the paths to resolve

Returns

String

the joined path

same (pathA, pathB)

Returns whether two paths refer to the same storage (file or directory), either by virtue of symbolic or hard links, such that modifying one would modify the other.

Parameters

String pathA

the first path
String pathB

the second path

Returns

Boolean

true iff the two paths locate the same file

sameFilesystem (pathA, pathB)

Returns whether two paths refer to an entity of the same file system.

Parameters

String pathA

the first path
String pathB

the second path

Returns

Boolean

true if same file system, otherwise false

size (path)

Returns the size of a file in bytes, or throws an exception if the path does not correspond to an accessible path, or is not a regular file or a link.

Parameters

String path

the file path

Returns

Number

the file size in bytes

Throws

Error if path is not a file

split (path)

Split a given path into an array of path components.

Example

>> fs.split('/Users/someuser/Desktop/subdir/test.txt');
[ '', 'Users', 'someuser', 'Desktop', 'subdir', 'test.txt' ]

Parameters

String path

Returns

Array

the path components

symbolicLink (existing, link)

Creates a symbolic link at the target path that refers to the source path. The concrete implementation depends on the file system and the operating system.

Parameters

String existing

path to an existing file, therefore the target of the link
String link

the link to create pointing to an existing path

Returns

String

the path to the symbolic link

touch (path, mtime)

Sets the modification time of a file or directory at a given path to a specified time, or the current time. Creates an empty file at the given path if no file or directory exists, using the default permissions.

Parameters

String path

the file path
Date mtime

optional date

workingDirectory ()

Return the path name of the current working directory.

Returns

String

the current working directory

write (path, content, options)

Open, write, flush, and close a file, writing the given content. If content is a ByteArray or ByteString from the binary module, binary mode is implied.

Parameters

String path
ByteArray|ByteString|String content
Object options

See

ByteArray or ByteString for binary data

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