ZenFS

ZenFS is a cross-platform library that emulates the Node.js filesystem API. It works using a system of backends, which are used by ZenFS to store and retrieve data. ZenFS should cover the full API surface of the latest Node.js version, though complex changes may lag a little bit.

Backends

ZenFS is modular and easily extended. The core includes some built-in backends:

• InMemory: Stores files in-memory. This is cleared when the runtime ends (e.g. a user navigating away from a web page or a Node process exiting)
• CopyOnWrite: Use readable and writable file systems with copy-on-write.
• Fetch: Downloads files over HTTP with the fetch API
• Port: Interacts with a remote over a MessagePort-like interface (e.g. a worker)
• Passthrough: Use an existing node:fs interface with ZenFS
• SingleBuffer: A backend contained within a single buffer. Can be used for synchronous multi-threaded operations using SharedArrayBuffer

ZenFS supports a number of other backends. Many are provided as separate packages under @zenfs. More backends can be defined by separate libraries by extending the FileSystem class and providing a Backend object.

You can find all of the packages available over on NPM. Below is a list of the backends included with some of them:

• @zenfs/archives: Zip, Iso
• @zenfs/cloud: Dropbox, GoogleDrive, S3Bucket
• @zenfs/dom: WebAccess (Web File System Access API/OPFS), IndexedDB, WebStorage (localStorage/sessionStorage), XML (DOM elements)
• @zenfs/emscripten: Emscripten and a plugin for Emscripten's file system API

As an added bonus, all ZenFS backends support synchronous operations. Additionally, all of the backends included with the core are cross-platform.

For more information, see the docs.

Installing

npm install @zenfs/core

If you're using ZenFS, especially for big projects, please consider supporting the project. Thousands of hours have been dedicated to its development. Your financial support would go a long way toward improving ZenFS and its community.

Usage

Important

Check out the ZenFS docs!

import { fs } from '@zenfs/core'; // You can also use the default export

fs.writeFileSync('/test.txt', 'You can do this anywhere, including browsers!');

const contents = fs.readFileSync('/test.txt', 'utf-8');
console.log(contents);

A single InMemory backend is created by default, mounted on /. To use different backends, and to mount more than one, configure ZenFS with configure. This mounts a zip file to /mnt/zip, in-memory storage to /tmp, and IndexedDB to /home:

import { configure, InMemory } from '@zenfs/core';
import { IndexedDB } from '@zenfs/dom';
import { Zip } from '@zenfs/archives';

const res = await fetch('mydata.zip');

await configure({
	mounts: {
		'/mnt/zip': { backend: Zip, data: await res.arrayBuffer() },
		'/tmp': InMemory,
		'/home': IndexedDB,
	},
});

The fs/promises API is available from @zenfs/core/promises, as the promises export, or as fs.promises.

For the full usage guide, see the documentation. This includes mounting at runtime, contexts and permissions, devices, and the node:*module emulation.

Bundling

ZenFS exports a drop-in for Node's fs module, so you can use it for your bundler of preference using the default export. See COPYING.md for more info.

Sponsors

A huge thank you to deco.cx for sponsoring ZenFS and helping to make this possible.

Contact and Support

You can reach out on Discord or by emailing jp@zenfs.dev