node-fs-extra Documentation

Node.js: extra methods for the fs object like copy(), remove(), mkdirs()

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Technical Documentation: jprichardson/node-fs-extra

ℹ️ Provenance: Multi-Tier Ingestion · CodeWiki Reference

Overview (`README.md`)

Node.js: fs-extra

fs-extra adds file system methods that aren't included in the native fs module and adds promise support to the fs methods. It also uses graceful-fs to prevent EMFILE errors. It should be a drop in replacement for fs.





Why?

I got tired of including mkdirp, rimraf, and ncp in most of my projects.

Installation

text
npm install fs-extra

Usage

CommonJS

fs-extra is a drop in replacement for native fs. All methods in fs are attached to fs-extra. All fs methods return promises if the callback isn't passed.

You don't ever need to include the original fs module again:

js
const fs = require('fs') // this is no longer necessary

you can now do this:

js
const fs = require('fs-extra')

or if you prefer to make it clear that you're using fs-extra and not fs, you may want
to name your fs variable fse like so:

js
const fse = require('fs-extra')

you can also keep both, but it's redundant:

js
const fs = require('fs')
const fse = require('fs-extra')

NOTE: The deprecated constants fs.F_OK, fs.R_OK, fs.W_OK, & fs.X_OK are not exported on Node.js v24.0.0+; please use their fs.constants equivalents.

ESM

There is also an fs-extra/esm import, that supports both default and named exports. However, note that fs methods are not included in fs-extra/esm; you still need to import fs and/or fs/promises separately:

js
import { readFileSync } from 'fs'
import { readFile } from 'fs/promises'
import { outputFile, outputFileSync } from 'fs-extra/esm'

Default exports are supported:

js
import fs from 'fs'
import fse from 'fs-extra/esm'
// fse.readFileSync is not a function; must use fs.readFileSync

but you probably want to just use regular fs-extra instead of fs-extra/esm for default exports:

js
import fs from 'fs-extra'
// both fs and fs-extra methods are defined

Sync vs Async vs Async/Await

Most methods are async by default. All async methods will return a promise if the callback isn't passed.

Sync methods on the other hand will throw if an error occurs.

Also Async/Await will throw an error if one occurs.

Example:

js
const fs = require('fs-extra')

// Async with promises:
fs.copy('/tmp/myfile', '/tmp/mynewfile')
  .then(() => console.log('success!'))
  .catch(err => console.error(err))

// Async with callbacks:
fs.copy('/tmp/myfile', '/tmp/mynewfile', err => {
  if (err) return console.error(err)
  console.log('success!')
})

// Sync:
try {
  fs.copySync('/tmp/myfile', '/tmp/mynewfile')
  console.log('success!')
} catch (err) {
  console.error(err)
}

// Async/Await:
async function copyFiles () {
  try {
    await fs.copy('/tmp/myfile', '/tmp/mynewfile')
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

copyFiles()

Methods

Async

Sync

NOTE: You can still use the native Node.js methods. They are promisified and copied over to fs-extra. See notes on fs.read(), fs.write(), & fs.writev()

What happened to `walk()` and `walkSync()`?

They were removed from fs-extra in v2.0.0. If you need the functionality, walk and walkSync are available as separate packages, klaw and klaw-sync.

Third Party

CLI

fse-cli allows you to run fs-extra from a console or from npm scripts.

TypeScript

If you like TypeScript, you can use fs-extra with it: https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/fs-extra

File / Directory Watching

If you want to watch for changes to files or directories, then you should use chokidar.

Obtain Filesystem (Devices, Partitions) Information

fs-filesystem allows you to read the state of the filesystem of the host on which it is run. It returns information about both the devices and the partitions (volumes) of the system.

Misc.

Hacking on fs-extra

Wanna hack on fs-extra? Great! Your help is needed! fs-extra is one of the most depended upon Node.js packages. This project
uses JavaScript Standard Style - if the name or style choices bother you,
you're gonna have to get over it :) If standard is good enough for npm, it's good enough for fs-extra.

What's needed?

  • First, take a look at existing issues. Those are probably going to be where the priority lies.
  • More tests for edge cases. Specifically on different platforms. There can never be enough tests.
  • Improve test coverage.

Note: If you make any big changes, you should definitely file an issue for discussion first.

Running the Test Suite

fs-extra contains hundreds of tests.

  • npm run lint: runs the linter (standard)
  • npm run unit: runs the unit tests
  • npm run unit-esm: runs tests for fs-extra/esm exports
  • npm test: runs the linter and all tests

When running unit tests, set the environment variable CROSS_DEVICE_PATH to the absolute path of an empty directory on another device (like a thumb drive) to enable cross-device move tests.

Windows

If you run the tests on the Windows and receive a lot of symbolic link EPERM permission errors, it's
because on Windows you need elevated privilege to create symbolic links. You can add this to your Windows's
account by following the instructions here: http://superuser.com/questions/104845/permission-to-make-symbolic-links-in-windows-7
However, I didn't have much luck doing this.

Since I develop on Mac OS X, I use VMWare Fusion for Windows testing. I create a shared folder that I map to a drive on Windows.
I open the Node.js command prompt and run as Administrator. I then map the network drive running the following command:

text
net use z: "\\vmware-host\Shared Folders"

I can then navigate to my fs-extra directory and run the tests.

Naming

I put a lot of thought into the naming of these functions. Inspired by @coolaj86's request. So he deserves much of the credit for raising the issue. See discussion(s) here:

First, I believe that in as many cases as possible, the Node.js naming schemes should be chosen. However, there are problems with the Node.js own naming schemes.

For example, fs.readFile() and fs.readdir(): the F is capitalized in File and the d is not capitalized in dir. Perhaps a bit pedantic, but they should still be consistent. Also, Node.js has chosen a lot of POSIX naming schemes, which I believe is great. See: fs.mkdir(), fs.rmdir(), fs.chown(), etc.

We have a dilemma though. How do you consistently name methods that perform the following POSIX commands: cp, cp -r, mkdir -p, and rm -rf?

My perspective: when in doubt, err on the side of simplicity. A directory is just a hierarchical grouping of directories and files. Consider that for a moment. So when you want to copy it or remove it, in most cases you'll want to copy or remove all of its contents. When you want to create a directory, if the directory that it's suppose to be contained in does not exist, then in most cases you'll want to create that too.

So, if you want to remove a file or a directory regardless of whether it has contents, just call fs.remove(path). If you want to copy a file or a directory whether it has contents, just call fs.copy(source, destination). If you want to create a directory regardless of whether its parent directories exist, just call fs.mkdirs(path) or fs.mkdirp(path).

Credit

fs-extra wouldn't be possible without using the modules from the following authors:

License

Licensed under MIT

Copyright (c) 2011-2024 JP Richardson

Overview (`test/readme.md`)

Looking for the test files? You can find all of the test files in lib/**/__tests__.

Overview (`lib/copy/__tests__/ncp/README.md`)

These tests came from: https://github.com/AvianFlu/ncp/tree/v1.0.1/test

Copy Sync (`docs/copy-sync.md`)

copySync(src, dest[, options])

Copy a file or directory. The directory can have contents.

  • src <String> Note that if src is a directory it will copy everything inside of this directory, not the entire directory itself (see issue #537).
  • dest <String> Note that if src is a file, dest cannot be a directory (see issue #323).
  • options <Object>
    • overwrite ``: overwrite existing file or directory, default is true. Note that the copy operation will silently fail if you set this to false and the destination exists. Use the errorOnExist option to change this behavior.
    • errorOnExist ``: when overwrite is false and the destination exists, throw an error. Default is false.
    • dereference ``: dereference symlinks, default is false.
    • preserveTimestamps ``: When true, will set last modification and access times to the ones of the original source files. When false, timestamp behavior is OS-dependent. Default is false.
    • filter <Function>: Function to filter copied files/directories. Return true to copy the item, false to ignore it.

Example:

js
const fs = require('fs-extra')

// copy file
fs.copySync('/tmp/myfile', '/tmp/mynewfile')

// copy directory, even if it has subdirectories or files
fs.copySync('/tmp/mydir', '/tmp/mynewdir')

Using filter function

js
const fs = require('fs-extra')

const filterFunc = (src, dest) => {
  // your logic here
  // it will be copied if return true
}

fs.copySync('/tmp/mydir', '/tmp/mynewdir', { filter: filterFunc })

Copy (`docs/copy.md`)

copy(src, dest[, options][, callback])

Copy a file or directory. The directory can have contents.

  • src <String> Note that if src is a directory it will copy everything inside of this directory, not the entire directory itself (see issue #537).
  • dest <String> Note that if src is a file, dest cannot be a directory (see issue #323).
  • options <Object>
    • overwrite ``: overwrite existing file or directory, default is true. Note that the copy operation will silently fail if you set this to false and the destination exists. Use the errorOnExist option to change this behavior.
    • errorOnExist ``: when overwrite is false and the destination exists, throw an error. Default is false.
    • dereference ``: dereference symlinks, default is false.
    • preserveTimestamps ``: When true, will set last modification and access times to the ones of the original source files. When false, timestamp behavior is OS-dependent. Default is false.
    • filter <Function>: Function to filter copied files/directories. Return true to copy the item, false to ignore it. Can also return a Promise that resolves to true or false (or pass in an async function).
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

// With a callback:
fs.copy('/tmp/myfile', '/tmp/mynewfile', err => {
  if (err) return console.error(err)
  console.log('success!')
}) // copies file

fs.copy('/tmp/mydir', '/tmp/mynewdir', err => {
  if (err) return console.error(err)
  console.log('success!')
}) // copies directory, even if it has subdirectories or files

// With Promises:
fs.copy('/tmp/myfile', '/tmp/mynewfile')
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example () {
  try {
    await fs.copy('/tmp/myfile', '/tmp/mynewfile')
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example()

Using filter function

js
const fs = require('fs-extra')

const filterFunc = (src, dest) => {
  // your logic here
  // it will be copied if return true
}

fs.copy('/tmp/mydir', '/tmp/mynewdir', { filter: filterFunc }, err => {
  if (err) return console.error(err)
  console.log('success!')
})

EmptyDir Sync (`docs/emptyDir-sync.md`)

emptyDirSync(dir)

Ensures that a directory is empty. Deletes directory contents if the directory is not empty. If the directory does not exist, it is created. The directory itself is not deleted.

Alias: emptydirSync()

  • dir <String>

Example:

js
const fs = require('fs-extra')

// assume this directory has a lot of files and folders
fs.emptyDirSync('/tmp/some/dir')

EmptyDir (`docs/emptyDir.md`)

emptyDir(dir[, callback])

Ensures that a directory is empty. Deletes directory contents if the directory is not empty. If the directory does not exist, it is created. The directory itself is not deleted.

Alias: emptydir()

  • dir <String>
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

// assume this directory has a lot of files and folders
// With a callback:
fs.emptyDir('/tmp/some/dir', err => {
  if (err) return console.error(err)
  console.log('success!')
})

// With Promises:
fs.emptyDir('/tmp/some/dir')
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example () {
  try {
    await fs.emptyDir('/tmp/some/dir')
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example()

EnsureDir Sync (`docs/ensureDir-sync.md`)

ensureDirSync(dir[,options])

Ensures that the directory exists. If the directory structure does not exist, it is created. If provided, options may specify the desired mode for the directory.

Aliases: mkdirsSync(), mkdirpSync()

  • dir <String>
  • options | <Object>
    • If it is Integer, it will be mode.
    • If it is Object, it will be { mode: }.

Example:

js
const fs = require('fs-extra')

const dir = '/tmp/this/path/does/not/exist'

const desiredMode = 0o2775
const options = {
  mode: 0o2775
}

fs.ensureDirSync(dir)
// dir has now been created, including the directory it is to be placed in

fs.ensureDirSync(dir, desiredMode)
// dir has now been created, including the directory it is to be placed in with permission 0o2775

fs.ensureDirSync(dir, options)
// dir has now been created, including the directory it is to be placed in with permission 0o2775

EnsureDir (`docs/ensureDir.md`)

ensureDir(dir[,options][,callback])

Ensures that the directory exists. If the directory structure does not exist, it is created.

Aliases: mkdirs(), mkdirp()

  • dir <String>
  • options | <Object>
    • If it is Integer, it will be mode.
    • If it is Object, it will be { mode: }.
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

const dir = '/tmp/this/path/does/not/exist'
const desiredMode = 0o2775
const options = {
  mode: 0o2775
}

// With a callback:
fs.ensureDir(dir, err => {
  console.log(err) // => null
  // dir has now been created, including the directory it is to be placed in
})

// With a callback and a mode integer
fs.ensureDir(dir, desiredMode, err => {
  console.log(err) // => null
  // dir has now been created with mode 0o2775, including the directory it is to be placed in
})

// With Promises:
fs.ensureDir(dir)
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With Promises and a mode integer:
fs.ensureDir(dir, desiredMode)
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (directory) {
  try {
    await fs.ensureDir(directory)
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}
example(dir)

// With async/await and an options object, containing mode:
async function exampleMode (directory) {
  try {
    await fs.ensureDir(directory, options)
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}
exampleMode(dir)

EnsureFile Sync (`docs/ensureFile-sync.md`)

ensureFileSync(file)

Ensures that the file exists. If the file that is requested to be created is in directories that do not exist, these directories are created. If the file already exists, it is NOT MODIFIED.

Alias: createFileSync()

  • file <String>

Example:

js
const fs = require('fs-extra')

const file = '/tmp/this/path/does/not/exist/file.txt'
fs.ensureFileSync(file)
// file has now been created, including the directory it is to be placed in

EnsureFile (`docs/ensureFile.md`)

ensureFile(file[, callback])

Ensures that the file exists. If the file that is requested to be created is in directories that do not exist, these directories are created. If the file already exists, it is NOT MODIFIED.

Alias: createFile()

  • file <String>
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

const file = '/tmp/this/path/does/not/exist/file.txt'

// With a callback:
fs.ensureFile(file, err => {
  console.log(err) // => null
  // file has now been created, including the directory it is to be placed in
})

// With Promises:
fs.ensureFile(file)
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (f) {
  try {
    await fs.ensureFile(f)
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example(file)

ensureLinkSync(srcPath, destPath)

Ensures that the link exists. If the directory structure does not exist, it is created.

Alias: createLinkSync()

  • srcPath <String>
  • destPath <String>

Example:

js
const fs = require('fs-extra')

const srcPath = '/tmp/file.txt'
const destPath = '/tmp/this/path/does/not/exist/file.txt'
fs.ensureLinkSync(srcPath, destPath)
// link has now been created, including the directory it is to be placed in

Ensures that the link exists. If the directory structure does not exist, it is created.

Alias: createLink()

  • srcPath <String>
  • destPath <String>
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

const srcPath = '/tmp/file.txt'
const destPath = '/tmp/this/path/does/not/exist/file.txt'

// With a callback:
fs.ensureLink(srcPath, destPath, err => {
  console.log(err) // => null
  // link has now been created, including the directory it is to be placed in
})

// With Promises:
fs.ensureLink(srcPath, destPath)
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (src, dest) {
  try {
    await fs.ensureLink(src, dest)
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example(srcPath, destPath)

ensureSymlinkSync(srcPath, destPath[, type])

Ensures that the symlink exists. If the directory structure does not exist, it is created.

Alias: createSymlinkSync()

  • srcPath <String>
  • destPath <String>
  • type <String> It is only available on Windows and ignored on other platforms. It can be set to dir, file, or junction.

Example:

js
const fs = require('fs-extra')

const srcPath = '/tmp/file.txt'
const destPath = '/tmp/this/path/does/not/exist/file.txt'
fs.ensureSymlinkSync(srcPath, destPath)
// symlink has now been created, including the directory it is to be placed in

Ensures that the symlink exists. If the directory structure does not exist, it is created.

Alias: createSymlink()

  • srcPath <String>
  • destPath <String>
  • type <String> It is only available on Windows and ignored on other platforms. It can be set to dir, file, or junction.
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

const srcPath = '/tmp/file.txt'
const destPath = '/tmp/this/path/does/not/exist/file.txt'

// With a callback:
fs.ensureSymlink(srcPath, destPath, err => {
  console.log(err) // => null
  // symlink has now been created, including the directory it is to be placed in
})

// With Promises:
fs.ensureSymlink(srcPath, destPath)
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (src, dest) {
  try {
    await fs.ensureSymlink(src, dest)
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example(srcPath, destPath)

Fs Read Write Writev (`docs/fs-read-write-writev.md`)

About `fs.read()` & `fs.write()`

fs.read(), fs.write(), & fs.writev() are different from other fs methods in that their callbacks are called with 3 arguments instead of the usual 2 arguments.

If you're using them with callbacks, they will behave as usual. However, their promise usage is a little different. fs-extra promisifies these methods like util.promisify() does.

Here's the example promise usage:

`fs.read()`

js
// With Promises:
fs.read(fd, buffer, offset, length, position)
  .then(results => {
    console.log(results)
    // { bytesRead: 20, buffer: <Buffer 0f 34 5d ...> }
  })

// With async/await:
async function example () {
  const { bytesRead, buffer } = await fs.read(fd, Buffer.alloc(length), offset, length, position)
}

`fs.write()`

js
// With Promises:
fs.write(fd, buffer, offset, length, position)
  .then(results => {
    console.log(results)
    // { bytesWritten: 20, buffer: <Buffer 0f 34 5d ...> }
  })

// With async/await:
async function example () {
  const { bytesWritten, buffer } = await fs.write(fd, Buffer.alloc(length), offset, length, position)
}

`fs.writev()`

js
// With async/await:
async function example () {
  const { bytesWritten, buffers } = await fs.writev(fd, buffers, position)
}

Move Sync (`docs/move-sync.md`)

moveSync(src, dest[, options])

Moves a file or directory, even across devices.

  • src <String>
  • dest <String> Note: When src is a file, dest must be a file and when src is a directory, dest must be a directory.
  • options <Object>
    • overwrite ``: overwrite existing file or directory, default is false.

Example:

js
const fs = require('fs-extra')

fs.moveSync('/tmp/somefile', '/tmp/does/not/exist/yet/somefile')

Using overwrite option

js
const fs = require('fs-extra')

fs.moveSync('/tmp/somedir', '/tmp/may/already/exist/somedir', { overwrite: true })

Move (`docs/move.md`)

move(src, dest[, options][, callback])

Moves a file or directory, even across devices.

  • src <String>
  • dest <String> Note: When src is a file, dest must be a file and when src is a directory, dest must be a directory.
  • options <Object>
    • overwrite ``: overwrite existing file or directory, default is false.
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

const src = '/tmp/file.txt'
const dest = '/tmp/this/path/does/not/exist/file.txt'

// With a callback:
fs.move(src, dest, err => {
  if (err) return console.error(err)
  console.log('success!')
})

// With Promises:
fs.move(src, dest)
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (src, dest) {
  try {
    await fs.move(src, dest)
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example(src, dest)

Using overwrite option

js
const fs = require('fs-extra')

fs.move('/tmp/somedir', '/tmp/may/already/exist/somedir', { overwrite: true }, err => {
  if (err) return console.error(err)
  console.log('success!')
})

OutputFile Sync (`docs/outputFile-sync.md`)

outputFileSync(file, data[, options])

Almost the same as writeFileSync (i.e. it overwrites), except that if the parent directory does not exist, it's created. file must be a file path (a buffer or a file descriptor is not allowed).

Example:

js
const fs = require('fs-extra')

const file = '/tmp/this/path/does/not/exist/file.txt'
fs.outputFileSync(file, 'hello!')

const data = fs.readFileSync(file, 'utf8')
console.log(data) // => hello!

OutputFile (`docs/outputFile.md`)

outputFile(file, data[, options][, callback])

Almost the same as writeFile (i.e. it overwrites), except that if the parent directory does not exist, it's created. file must be a file path (a buffer or a file descriptor is not allowed).

  • file <String>
  • data <String> | |
  • options <Object> | <String> (the same as fs.writeFile() options)
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

const file = '/tmp/this/path/does/not/exist/file.txt'

// With a callback:
fs.outputFile(file, 'hello!', err => {
  console.log(err) // => null

  fs.readFile(file, 'utf8', (err, data) => {
    if (err) return console.error(err)
    console.log(data) // => hello!
  })
})

// With Promises:
fs.outputFile(file, 'hello!')
.then(() => fs.readFile(file, 'utf8'))
.then(data => {
  console.log(data) // => hello!
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (f) {
  try {
    await fs.outputFile(f, 'hello!')

    const data = await fs.readFile(f, 'utf8')

    console.log(data) // => hello!
  } catch (err) {
    console.error(err)
  }
}

example(file)

OutputJson Sync (`docs/outputJson-sync.md`)

outputJsonSync(file, object[, options])

Almost the same as writeJsonSync, except that if the directory does not exist, it's created.

Alias: outputJSONSync()

  • file <String>
  • object <Object>
  • options <Object>
    • spaces <Number> | <String> Number of spaces to indent; or a string to use for indentation (i.e. pass '\t' for tab indentation). See the docs for more info.
    • EOL <String> Set EOL character. Default is \n.
    • replacer JSON replacer
    • Also accepts fs.writeFileSync() options

Example:

js
const fs = require('fs-extra')

const file = '/tmp/this/path/does/not/exist/file.json'
fs.outputJsonSync(file, {name: 'JP'})

const data = fs.readJsonSync(file)
console.log(data.name) // => JP

OutputJson (`docs/outputJson.md`)

outputJson(file, object[, options][, callback])

Almost the same as writeJson, except that if the directory does not exist, it's created.

Alias: outputJSON()

  • file <String>
  • object <Object>
  • options <Object>
    • spaces <Number> | <String> Number of spaces to indent; or a string to use for indentation (i.e. pass '\t' for tab indentation). See the docs for more info.
    • EOL <String> Set EOL character. Default is \n.
    • replacer JSON replacer
    • Also accepts fs.writeFile() options
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

const file = '/tmp/this/path/does/not/exist/file.json'

// With a callback:
fs.outputJson(file, {name: 'JP'}, err => {
  console.log(err) // => null

  fs.readJson(file, (err, data) => {
    if (err) return console.error(err)
    console.log(data.name) // => JP
  })
})

// With Promises:
fs.outputJson(file, {name: 'JP'})
.then(() => fs.readJson(file))
.then(data => {
  console.log(data.name) // => JP
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (f) {
  try {
    await fs.outputJson(f, {name: 'JP'})

    const data = await fs.readJson(f)

    console.log(data.name) // => JP
  } catch (err) {
    console.error(err)
  }
}

example(file)

PathExists Sync (`docs/pathExists-sync.md`)

pathExistsSync(file)

An alias for fs.existsSync(), created for consistency with pathExists().

PathExists (`docs/pathExists.md`)

pathExists(file[, callback])

Test whether or not the given path exists by checking with the file system. Like fs.exists, but with a normal callback signature (err, exists). Uses fs.access under the hood.

  • file <String>
  • callback <Function>
    • err <Error>
    • exists ``

Example:

js
const fs = require('fs-extra')

const file = '/tmp/this/path/does/not/exist/file.txt'

// With a callback:
fs.pathExists(file, (err, exists) => {
  console.log(err) // => null
  console.log(exists) // => false
})

// Promise usage:
fs.pathExists(file)
  .then(exists => console.log(exists)) // => false

// With async/await:
async function example (f) {
  const exists = await fs.pathExists(f)

  console.log(exists) // => false
}

example(file)

ReadJson Sync (`docs/readJson-sync.md`)

readJsonSync(file[, options])

Reads a JSON file and then parses it into an object.

Alias: readJSONSync()

Example:

js
const fs = require('fs-extra')

const packageObj = fs.readJsonSync('./package.json')
console.log(packageObj.version) // => 2.0.0

readJsonSync() can take a throws option set to false and it won't throw if the JSON is invalid. Example:

js
const fs = require('fs-extra')

const file = '/tmp/some-invalid.json'
const data = '{not valid JSON'
fs.writeFileSync(file, data)

const obj = fs.readJsonSync(file, { throws: false })
console.log(obj) // => null

ReadJson (`docs/readJson.md`)

readJson(file[, options][, callback])

Reads a JSON file and then parses it into an object.

Alias: readJSON()

Example:

js
const fs = require('fs-extra')

// With a callback:
fs.readJson('./package.json', (err, packageObj) => {
  if (err) console.error(err)
  console.log(packageObj.version) // => 0.1.3
})

// With Promises:
fs.readJson('./package.json')
.then(packageObj => {
  console.log(packageObj.version) // => 0.1.3
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example () {
  try {
    const packageObj = await fs.readJson('./package.json')
    console.log(packageObj.version) // => 0.1.3
  } catch (err) {
    console.error(err)
  }
}

example()

readJson() can take a throws option set to false and it won't throw if the JSON is invalid. Example:

js
const fs = require('fs-extra')

const file = '/tmp/some-invalid.json'
const data = '{not valid JSON'
fs.writeFileSync(file, data)

// With a callback:
fs.readJson(file, { throws: false }, (err, obj) => {
  if (err) console.error(err)
  console.log(obj) // => null
})

// With Promises:
fs.readJson(file, { throws: false })
.then(obj => {
  console.log(obj) // => null
})
.catch(err => {
  console.error(err) // Not called
})

// With async/await:
async function example (f) {
  const obj = await fs.readJson(f, { throws: false })
  console.log(obj) // => null
}

example(file)

Remove Sync (`docs/remove-sync.md`)

removeSync(path)

Removes a file or directory. The directory can have contents. If the path does not exist, silently does nothing.

  • path <String>

Example:

js
const fs = require('fs-extra')

// remove file
fs.removeSync('/tmp/myfile')

fs.removeSync('/home/jprichardson') // I just deleted my entire HOME directory.

Remove (`docs/remove.md`)

remove(path[, callback])

Removes a file or directory. The directory can have contents. If the path does not exist, silently does nothing.

  • path <String>
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

// remove file
// With a callback:
fs.remove('/tmp/myfile', err => {
  if (err) return console.error(err)
  console.log('success!')
})

fs.remove('/home/jprichardson', err => {
  if (err) return console.error(err)
  console.log('success!') // I just deleted my entire HOME directory.
})

// With Promises:
fs.remove('/tmp/myfile')
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example (src, dest) {
  try {
    await fs.remove('/tmp/myfile')
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example()

WriteJson Sync (`docs/writeJson-sync.md`)

writeJsonSync(file, object[, options])

Writes an object to a JSON file.

Alias: writeJSONSync()

  • file <String>
  • object <Object>
  • options <Object>
    • spaces <Number> | <String> Number of spaces to indent; or a string to use for indentation (i.e. pass '\t' for tab indentation). See the docs for more info.
    • EOL <String> Set EOL character. Default is \n.
    • replacer JSON replacer
    • Also accepts fs.writeFileSync() options

Example:

js
const fs = require('fs-extra')

fs.writeJsonSync('./package.json', {name: 'fs-extra'})

See also: outputJsonSync()

WriteJson (`docs/writeJson.md`)

writeJson(file, object[, options][, callback])

Writes an object to a JSON file.

Alias: writeJSON()

  • file <String>
  • object <Object>
  • options <Object>
    • spaces <Number> | <String> Number of spaces to indent; or a string to use for indentation (i.e. pass '\t' for tab indentation). See the docs for more info.
    • EOL <String> Set EOL character. Default is \n.
    • replacer JSON replacer
    • Also accepts fs.writeFile() options
  • callback <Function>
    • err <Error>

Example:

js
const fs = require('fs-extra')

// With a callback:
fs.writeJson('./package.json', {name: 'fs-extra'}, err => {
  if (err) return console.error(err)
  console.log('success!')
})

// With Promises:
fs.writeJson('./package.json', {name: 'fs-extra'})
.then(() => {
  console.log('success!')
})
.catch(err => {
  console.error(err)
})

// With async/await:
async function example () {
  try {
    await fs.writeJson('./package.json', {name: 'fs-extra'})
    console.log('success!')
  } catch (err) {
    console.error(err)
  }
}

example()

See also: outputJson()

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