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11.3.5 • Public • Published

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modern-fs-extra: fs-extra for the 21st century

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@3xpo/fs-extra (alongside upstream 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 the fork?

I got tired of including @types/fs-extra in most of my projects. I also wanted a package that can do ESM and CJS without needing to inline the package in my output.


pnpm i @3xpo/fs-extra



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

This fork modifies the internal callback beahviour a bit, and you may not be able to use a callback everywhere. Unlike the upstream, promises are usually returned even if you do pass a callback.

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

import * as fs from 'fs'; // this is no longer necessary

you can now do this:

import fs from '@3xpo/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:

import fse from '@3xpo/fs-extra';

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

import * as fs from 'fs';
import fse from '@3xpo/fs-extra';


Unlike our upstream, we package both native ESM and CJS variants - both require() and import will work just fine


As mentioned above, you can simply use:

const fs = require('@3xpo/fs-extra');

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.


import fs from '@3xpo/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);

// Sync:
try {
  fs.copySync('/tmp/myfile', '/tmp/mynewfile');
} catch (err) {

// Async/Await:
async function copyFiles() {
  try {
    await fs.copy('/tmp/myfile', '/tmp/mynewfile');
  } catch (err) {





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


fse-cli allows you to run fs-extra from a console or from npm scripts. fse-cli uses upstream fs-extra. it does not support this fork.


If you like TypeScript, you can use fs-extra with it; we ship types!

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. fs-filesystem is deprecated.


Both of these use upstream fs-extra. They don't support this fork out of the box.

If someone's interested in me maintaining a variant of either of these, open an issue!

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 (although this fork isn't, contribs are still nice).

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 JS Standard Style is overcomplicated & overly strict for no reason; we use a minimal prettier configuration. If you use single quotes & an indent size of 2, and don't code like a maniac, you're basically fine. camelCase is preferred for everything except classes; where PascalCase is used.

You'll need pnpm, aswell as the monorepo this package is housed in. You shouldn't need much else.

What's needed?

  • First, take a look at existing issues, both in upstream and in the monorepo. 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.
  • Get new upstream commits into this fork! We split off of upstream at acf5585 and are currently in parity with 1d931c8; getting anything done since then on the upstream fs-extra repository implemented here would be amazing. Sadly, if and when this happens, this is a significant amount of work due to the entire codebase being refactoed in a different language. As such, wherever possible, just re-implement equivalent changes in the fork.
  • Provide more features! If you have a use-case for @3xpo/fs-extra that it isn't fulfilling, feel free to open an issue! Make sure to prefix the issue's title with fs-extra: :)

Note: If you make any extremely large changes, you should definitely file an issue for discussion first - however if you decide you want the feature in your fork regardless of if it gets merged, feel free to open a PR without a prior issue existing.

Running the Test Suite

@3xpo/fs-extra contains hundreds of tests.

  • pnpm build: builds the project
  • pnpm test: runs the test suite
  • you don't need anything else

When running unit tests, when possible, 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.


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, the upstream author didn't have much luck doing this.

In regards to shared folders, the upstream author's suggestions should likely be followed.


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).


@3xpo/fs-extra wouldn't be possible without using the modules from the following authors:


Licensed under MIT

Copyright (c) 2024 Expo

Copyright (c) 2011-2017 JP Richardson

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