@wasmer/wasmfs

Isomorphic library to provide a sandboxed node fs implementation for Node and Browsers. 📂

Table of Contents

• Features
• Installation
• Quick Start
• Reference API
• Contributing

Features

This project forks memfs with custom fixes to work properly with the WebAssembly/WASI ecosystem.

This package provides the following features:

• In-memory file-system with Node's fs API using memfs. 🗄️
• Scaffolds common files used by the Wasmer Runtime (e.g I/O Device files like /dev/stdout), to provide a similar experience to the Wasmer Runtime. 🔌
• Provides convienence functions for grabbing Input / Output. ↔️
• Allows overriding read/write of individual files to allow for custom implementations. 🛠️

Installation

For installing @wasmer/wasmfs, just run this command in your shell:

npm install --save @wasmer/wasmfs

Quick Start

import { WasmFs } from '@wasmer/wasmfs';

const wasmFs = new WasmFs();

wasmFs.fs.writeFileSync('/dev/stdout', 'Quick Start!');

wasmFs.getStdOut().then(response => {
  console.log(response); // Would log: 'Quick Start!'
});

For a larger end-to-end example, please see the @wasmer/wasm-terminal package.

Reference API

wasmFs.fs

memfs' node fs implementation object. See the node fs documentation for API usage.

NOTE: The functions on this fs implementation can easily be overriden to provide custom functionality when your wasm module (running with @wasmer/wasi) tries to do file system operations. For example:

const wasmFs = new WasmFs();

const originalWriteFileSync = wasmFs.fs.writeFileSync;
wasmFs.fs.writeFileSync = (path, text) => {
  console.log('File written:', path);
  originalWriteFileSync(path, text);
};

wasmFs.fs.writeFileSync('/dev/stdout', 'Quick Start!');

// Would log: "File written: /dev/stdout"

wasmFs.getStdOut()

Function that returns a promise that resolves a string. With the file contents of /dev/stdout.

Contributing

This project follows the all-contributors specification.

Contributions of any kind are welcome! 👍