Filesystem

Introduction

Working with the filesystem in Node.js can be cumbersome, especially in combination with a code base using async/await. That’s the reason Supercharge provides you a handy filesystem abstraction. This sparks developer joy because Supercharge’s filesystem package is fully async. Every method in the Supercharge filesystem package is async and returns a promise to keep the consistency.

Retrieve the filesystem package in Supercharge like this:

const Fs = require('@supercharge/framework/filesystem')

Retrieve Files & Directories

Read files from the local disk using Fs.readFile(path). This method returns the raw file content as string value:

const Fs = require('@supercharge/framework/filesystem')

const content = await Fs.readFile('file.text')

Use Fs.exists(path) to determine whether a given file or directory exists on your disk:

const exists = await Fs.exists('file.text')

To check whether a given path does not exist on the disk, use Fs.notExists(path):

const nope = await Fs.notExists('file.text')

Retrieve Directories

You can retrieve a list of files within a directory using Fs.files(path). Notice: this won’t step into subdirectories that may exist within the given path:

const files = await Fs.files(path)

Retrieve all files recursively within a directories and its subdirectores, use Fs.allFiles(path):

const allFiles = await Fs.allFiles(path)

File Metadata

Additinally to reading, storing, or deleting files and directories, you may retrieve metadata about the files themselves. Node.js ships with a Stats class providing a handful of properties about a file.

Use Fs.stat(file) to retrieve a Stats instance of a file:

const stats = await Fs.stat('avatar.png'))

You may also check whether a given path is a file using Fs.isFile(path):

const isFile = await Fs.isFile('avatar.png'))
// true

Use Fs.isDirectory(path) to check if a path is a directory:

const isDirectory = await Fs.isDirectory('path/to/dir/avatar.png'))
// false

const isDirectory = await Fs.isDirectory('path/to/dir'))
// true

In some cases it’s helpful to determine the last modified date of a file. Use Fs.lastModified(file) to retrieve the last modified JavaScript date of the given file:

const date = await Fs.lastModified('logo.png'))

With Fs.lastAccessed(file) you retrieve a JavaScript date of the last time someone accessed the file:

const date = await Fs.lastAccessed('file.png'))

To ensure if your application can access a given file, you may use Fs.canAccess(file):

const canAccess = await Fs.canAccess('file.png'))

Retrieve a file’s extension with Fs.extension(file):

const extension = await Fs.extension('blog.md'))
// '.md'

The basename of a file returns the last part of a path. Retrieve the basename of a file using Fs.basename(file):

const basename = await Fs.basename('/storage/app/blog.md'))
// 'blog.md'

If you only want the actual filename without the extension, use Fs.filename(file):

const date = await Fs.filename('/storage/app/blog.md'))
// 'blog'

The Fs.dirname(path) method returns the directory name of a given path:

const date = await Fs.dirname('/storage/app/blog.md'))
// /storage/app

Saving Files

Writing content to a file requires a file handle to exist on the local file system. To ensure a file actually exists, you may use Fs.ensureFile(path) method. This creates a new file if it doesn’t already exists. It won’t override an existing file:

await Fs.ensureFile('storage/app/blog/tutorial-1.md')

You may write content to a file on your disk using Fs.writeFile(path, content):

await Fs.writeFile('storage/app/blog/tutorial-1.md', '# Tutorial Title')

Use Fs.copy(source, dest) to duplicate an existing file and copy it from the source to a destination:

await Fs.copy('tutorial-1.md', 'tutorial-2.md')

For situations where you want to move a file on the disk, use Fs.move(from, to):

await Fs.move('tutorial-1.md', 'archive/tutorial-1.md')

In some situations, it’s helpful to adjust the permissions of files or directories. Use Fs.chmod(file) to adjust the permissions. Pass in an integer value and the framework translates it to the required “oct” value:

await Fs.chmod(file, 600)

Create a link from an existing file to a linked file using Fs.ensureLink(from, to):

await Fs.ensureLink('archive/tutorial-1.md', 'posts/tutorial-1.md')

You may also create symbolic links using await Fs.ensureSymlink(from, to):

await Fs.ensureSymlink('archive/tutorial-1.md', 'posts/tutorial-1.md')

Windows restricts the creation of symlinks to admin users. You need to grant your user additional permissions to create symlinks. If your user is part of the admin group, you always need to run your code with administrator rights.

If you you run into operation not permitted errors while creating symlinks on Windows, have a look at your user permissions.

If you need a temporary file, you can use Fs.tempFile(file) to create a handle in a location where the operating system automatically cleans it up:

const tempAvatar = await Fs.tempFile('user-1-avatar-upload')
await Fs.writeFile(tempAvatar, content)

Lock Files

You application may require file locks on your file system to ensure a correct processing flow. This may be helpful in setups using parallel processing.

You may create a file lock using Fs.lock(file):

await Fs.lock('tutorial-1.md')

Release a lock on a file using Fs.unlock(file)

await Fs.unlock('tutorial-1.md')

Determine whether a given file is currently locked, use the Fs.isLocked(file) method:

await Fs.isLocked('tutorial-1.md')

Create Directories

Structuring files on your local hard drive may require directories. Create a new directory using Fs.ensureDir(path). This creates a new directory at the given path if it doesn’t already exists. It won’t override an existing path:

await Fs.ensureDir('storage/avatars')

For a temporary directory, use Fs.tempDir(path). This temporary folder will be created in a location where the operating system automatically cleans up after a certain time period. You don’t need to remove it manually:

await Fs.tempDir('storage/avatars')

Deleting Files & Directories

Delete single files from the file system using Fs.remove(path):

if (await Fs.exists(path)) {
  await Fs.remove(path)
}

You can remove all files and subdirectories in a given directory using Fs.emptyDir(path):

await Fs.emptyDir(path)