fs-extra adds file system methods that aren't included in the native
fs module and adds promise support to the
fs methods. It should be a drop in replacement for
I got tired of including
ncp in most of my projects.
npm install --save fs-extra
fs-extra is a drop in replacement for native
fs. All methods in
fs are attached to
fs methods return promises if the callback isn't passed.
You don't ever need to include the original
fs module again:
const fs = // this is no longer necessary
you can now do this:
const fs =
or if you prefer to make it clear that you're using
fs-extra and not
fs, you may want
to name your
fse like so:
const fse =
you can also keep both, but it's redundant:
const fs =const fse =
Sync vs Async
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.
const fs =// Async with promises:fs// Async with callbacks:fs// Sync:tryfsconsolecatch errconsole
NOTE: You can still use the native Node.js methods. They are promisified and copied over to
What happened to
If you like TypeScript, you can use
fs-extra with it: https://github.com/borisyankov/DefinitelyTyped/tree/master/fs-extra
File / Directory Watching
If you want to watch for changes to files or directories, then you should use chokidar.
- mfs - Monitor your fs-extra calls.
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
you're gonna have to get over it :) If
standard is good enough for
npm, it's good enough for
- 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. See coveralls output for more info.
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 test: runs both the linter and the 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, 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:
net use z: "\\vmware-host\Shared Folders"
I can then navigate to my
fs-extra directory and run the tests.
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.
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:
We have a dilemma though. How do you consistently name methods that perform the following POSIX commands:
mkdir -p, and
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-extra wouldn't be possible without using the modules from the following authors:
Licensed under MIT
Copyright (c) 2011-2017 JP Richardson