Node.js: fs-extra

This module adds a few extra file system methods that aren't included in the native fs module. It is a drop in replacement for fs.

Why?

I got tired of including mkdirp, rimraf, and cp -r in most of my projects.

Installation

npm install --save fs-extra

Usage

fs-extra is a drop in replacement for native fs. All methods in fs are unmodified and attached to fs-extra.

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

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

you can now do this:

var fs = require('fs-extra'); //var fs = require('fs')

or if you prefer to make it clear that you're using fs-extra and not fs, you may want to do this:

//var fs = require('fs')
var fse = require('fs-extra')

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

var fs = require('fs')
var fse = require('fs-extra')

Methods

NOTE: You can still use the native Node.js methods. They are copied over to fs-extra.

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

Copy a file or directory. The directory can have contents. Like cp -r.

Sync: copySync()

Examples:

var fs = require('fs-extra');

fs.copy('/tmp/myfile', '/tmp/mynewfile', function(err){
  if (err) return console.error(err);
  console.log("success!")
}); //copies file

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

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()

Sync: createFileSync(),ensureFileSync()

Example:

var fs = require('fs-extra')

var file = '/tmp/this/path/does/not/exist/file.txt'
fs.ensureFile(file, function(err) {
  console.log(err); //null
  //file has now been created, including the directory it is to be placed in
})

ensureDir(dir, callback)

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

Sync: ensureDirSync()

Example:

var fs = require('fs-extra')

var dir = '/tmp/this/path/does/not/exist'
fs.ensureDir(dir, function(err) {
  console.log(err); //null
  //dir has now been created, including the directory it is to be placed in
})

mkdirs(dir, callback)

Creates a directory. If the parent hierarchy doesn't exist, it's created. Like mkdir -p.

Alias: mkdirp()

Sync: mkdirsSync() / mkdirpSync()

Examples:

var fs = require('fs-extra');

fs.mkdirs('/tmp/some/long/path/that/prob/doesnt/exist', function(err){
  if (err) return console.error(err);
  console.log("success!")
});

fs.mkdirsSync('/tmp/another/path');

move(src, dest, callback)

Moves a file or directory, even across devices.

Example:

var fs = require('fs-extra');

fs.move('/tmp/somefile', '/tmp/does/not/exist/yet/somefile', function(err){
  if (err) return console.error(err);
  console.log("success!")
});

outputFile(file, data, callback)

Almost the same as writeFile (i.e. it overwrites), except that if the parent directory does not exist, it's created.

Sync: outputFileSync()

Example:

var fs = require('fs-extra')
var file = '/tmp/this/path/does/not/exist/file.txt'

fs.outputFile(file, 'hello!', function(err) {
  console.log(err); //null

  fs.readFile(file, 'utf8', function(err, data) {
    console.log(data); //hello!
  })
})

outputJson(file, data, callback)

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

Alias: `outputJSON()

Sync: outputJsonSync(), outputJSONSync()

Example:

var fs = require('fs-extra')
var file = '/tmp/this/path/does/not/exist/file.txt'

fs.outputJson(file, {name: 'JP'}, function(err) {
  console.log(err); //null

  fs.readJson(file, function(err, data) {
    console.log(data.name); //'JP
  })
})

readJson(file, [options], callback)

Reads a JSON file and then parses it into an object. options are the same that you'd pass to fs.readFile.

Alias: readJSON()

Sync: readJsonSync(), readJSONSync()

Example:

var fs = require('fs-extra');

fs.readJson('./package.json', function(err, packageObj) {
  console.log(packageObj.version); //0.1.3
});

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

var fs = require('fs-extra')
var file = path.join('/tmp/some-invalid.json')
var data = "{not valid JSON"
fs.writeFileSync(file, data)

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

remove(dir, callback)

Removes a file or directory. The directory can have contents. Like rm -rf.

Alias: delete()

Sync: removeSync() / deleteSync()

Examples:

var fs = require('fs-extra');

fs.remove('/tmp/myfile', function(err){
  if (err) return console.error(err);
  
  console.log("success!")
});

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

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

Writes an object to a JSON file. options are the same that you'd pass to fs.readFile.

Alias: writeJSON()

Sync: writeJsonSync(), writeJSONSync()

Example:

var fs = require('fs-extra');
fs.writeJson('./package.json', {name: 'fs-extra'}, function(err){
  console.log(err);
});

Roadmap

This contains items that I'm considering doing. I'd love community feedback.

• File system walker. I really like this one: https://github.com/daaku/nodejs-walker ... this might be adding too much. Thoughts?
• File/directory tree watcher. There are quite a few. ... this also might be adding too much. I like this one: https://github.com/paulmillr/chokidar, thoughts?

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:

• jprichardson#2
• flatiron/utile#11
• ryanmcgrath/wrench-js#29
• https://github.com/substack/node-mkdirp/issues/17

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) or its alias fs.delete(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:

• Isaac Shlueter
• Charlie McConnel
• James Halliday
• Andrew Kelley

Contributions

If you want to contribute, please add a test. Also, don't change the version in package.json.

Contributors

• [*] JP Richardson
• [*] Mike McNeil
• [*] Ian Crowther
• [*] Stephen Mathieson
• [*] Srirangan
• [*] Uli Köhler
• 1 Jim Higson
• 1 PatrickJS
• 1 Michael Tiller
• <your name here>

License

Licensed under MIT

Copyright (c) 2011-2014 JP Richardson