@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
• fs.withOwner added
• fs.withOwnerSync added
• fs.cp polyfill for node < 16.7.0

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()