@npmcli/fs

What is @npmcli/fs?

The @npmcli/fs package is a file system utility library that provides a set of asynchronous file system methods. It is designed to offer more convenient and higher-level operations for interacting with the file system in Node.js applications. This package is particularly useful for tasks like reading, writing, and manipulating files and directories in a way that's compatible with the rest of the npm CLI ecosystem.

What are @npmcli/fs's main functionalities?

Reading files

This feature allows you to asynchronously read the contents of a file. The code sample demonstrates how to read a file and handle the promise returned by the readFile method.

const { readFile } = require('@npmcli/fs');
readFile('path/to/file.txt', 'utf8').then(contents => {
  console.log(contents);
}).catch(error => {
  console.error('Error reading file:', error);
});

Writing files

This feature enables you to write data to a file asynchronously. The code sample shows how to write a string to a file and handle the promise to catch any errors.

const { writeFile } = require('@npmcli/fs');
const content = 'Hello, world!';
writeFile('path/to/file.txt', content, 'utf8').then(() => {
  console.log('File written successfully');
}).catch(error => {
  console.error('Error writing file:', error);
});

Removing files

This feature provides a way to asynchronously remove a file. The code sample illustrates how to delete a file and handle the promise to catch errors.

const { unlink } = require('@npmcli/fs');
unlink('path/to/file.txt').then(() => {
  console.log('File removed successfully');
}).catch(error => {
  console.error('Error removing file:', error);
});

Other packages similar to @npmcli/fs

fs-extra

fs-extra is a popular npm package that extends the built-in Node.js fs module. It adds file system methods that aren't included in the native fs module, such as copying directories and files, removing directories, and ensuring directories exist. Compared to @npmcli/fs, fs-extra offers a broader set of file system operations and is widely used for its convenience methods.

rimraf

rimraf is a Node.js package that provides a simple way to remove files and directories, mimicking the UNIX command `rm -rf`. It's specifically focused on deletion operations, making it more specialized compared to @npmcli/fs, which offers a variety of file system operations including reading, writing, and removing files.

README

@npmcli/fs

polyfills, and extensions, of the core fs module.

Features

• all exposed functions return promises
• fs.rm polyfill for node versions < 14.14.0
• fs.mkdir polyfill adding support for the recursive and force options in node versions < 10.12.0
• fs.copyFile extended to accept an owner option
• fs.mkdir extended to accept an owner option
• fs.mkdtemp extended to accept an owner option
• fs.writeFile extended to accept an owner option
• fs.withTempDir added

The owner option

The copyFile, mkdir, mkdtemp, writeFile, and withTempDir functions all accept a new owner property in their options. It can be used in two ways:

• { owner: { uid: 100, gid: 100 } } - set the uid and gid explicitly
• { owner: 100 } - use one value, will set both uid and gid the same

The special string 'inherit' may be passed instead of a number, which will cause this module to automatically determine the correct uid and/or gid from the nearest existing parent directory of the target.

fs.withTempDir(root, fn, options) -> Promise

Parameters

• root: the directory in which to create the temporary directory
• fn: a function that will be called with the path to the temporary directory
• options
  • tmpPrefix: a prefix to be used in the generated directory name

Usage

The withTempDir function creates a temporary directory, runs the provided function (fn), then removes the temporary directory and resolves or rejects based on the result of fn.

const fs = require('@npmcli/fs')
const os = require('os')

// this function will be called with the full path to the temporary directory
// it is called with `await` behind the scenes, so can be async if desired.
const myFunction = async (tempPath) => {
  return 'done!'
}

const main = async () => {
  const result = await fs.withTempDir(os.tmpdir(), myFunction)
  // result === 'done!'
}

main()