memfs

memfs

In-memory file system with Node.js fs API and browser File System (Access) API.

Overview

memfs is a JavaScript library that implements an in-memory file system compatible with Node.js fs module and the browser File System (Access) API. Use it for testing, mocking file systems, or creating virtual file systems in both Node.js and browser environments.

Installation

npm install memfs

Quick Start

Node.js fs API

import { fs } from 'memfs';

// Write a file
fs.writeFileSync('/hello.txt', 'Hello, World!');

// Read a file
const content = fs.readFileSync('/hello.txt', 'utf-8');
console.log(content); // "Hello, World!"

// Create a directory
fs.mkdirSync('/mydir');

// List directory contents
console.log(fs.readdirSync('/')); // ['hello.txt', 'mydir']

Browser File System API

import { fsa } from 'memfs';

// Get root directory handle
const root = await fsa.getRoot();

// Create a file
const file = await root.getFileHandle('hello.txt', { create: true });
const writable = await file.createWritable();
await writable.write('Hello, World!');
await writable.close();

// Read the file
const readable = await file.getFile();
const text = await readable.text();
console.log(text); // "Hello, World!"

Features

• Node.js fs module API compatibility
• Browser File System (Access) API implementation
• Adapters between fs and File System API
• Directory snapshots and tree printing utilities
• Works in Node.js and modern browsers
• TypeScript support

Documentation

For detailed documentation and more examples, visit the main project page.

License

Apache 2.0

Similar packages

Other packages similar to memfs

mock-fs

mock-fs is a package that provides a mock file system for Node.js. It is similar to memfs in that it allows you to create an in-memory file system for testing purposes. However, mock-fs overrides the native fs module, while memfs provides a separate file system instance.

unionfs

unionfs is a package that can combine multiple file systems into a single cohesive file system interface. It can be used with memfs to overlay an in-memory file system on top of the real file system, providing a way to mix real and virtual file system operations.

fs-mock

fs-mock is another in-memory file system module for Node.js. It offers similar functionality to memfs, allowing you to mock the fs module for testing. It differs in API and implementation details, and the choice between fs-mock and memfs may come down to personal preference or specific use-case requirements.