wasabio

WebAssembly and SharedArrayBuffer IO. Pronounced "wassabee-yo".

• Purpose
• Usage
  • API
  • Initialization
    • From New Memory
    • From Existing Memory
  • Webpack Plugin

Purpose

wasabio offers several utility APIs with familiar interfaces, and implemented to work over a single SharedArrayBuffer and inside a TS-wrapped WASM module.

wasabio provides infrastructure for multi threaded applications running in web browsers, enabling safe cross-worker communication and shared state.

wasabio can be used in bundlers like Webpack to allow for an exchange between node core modules and its own implementations to seamlessly run in the browser.

Currently wasabio provides:

• Node's FileSystem API (implemented on top of an in-memory POSIX filesystem)
• LocalStorage API (implemented on top of an in-memory key-value store)
• Node's EventEmitter API (implemented on top of a SharedArrayBuffer)
• Low level Locks, Buses, Channels, and various other utilities

Usage

API

All APIs are spec-compatible with their original counterparts.

note: library needs to be initialized before use, see below.

import {
	localStorage, // in-memory key-value store for cross worker state storage
	EventEmitter, // lets you make named emitter for cross worker communication
	readFile,
	writeFile,
	appendFile,
	readFileSync,
	writeFileSync,
	appendFileSync,
	// ... Node FS api
} from "wasabio";

Some utility functions are also provided:

// return true if library is initialized
available(): boolean;
// serializes memory to a buffer, sets the thread counter to 0
serialize(memory: WebAssembly.Memory): Uint8Array;
// deserializes buffer to memory, sets the correct buffer size
deserialize(buffer: Uint8Array): WebAssembly.Memory;
// compresses serialized wasabio memory buffer into a zip buffer
compress(buffer: Uint8Array): Promise<Uint8Array>
// decompresses zip buffer into serialized wasabio memory buffer
decompress(buffer: Uint8Array): Promise<Uint8Array>

Initialization

From New Memory

Initialize wasabio on the first thread (usually the main thread) like so:

// main.ts
import { initialize } from "wasabio";
const mem = await initialize();
// some time later
worker.postMessage(mem);

On other threads (workers, frames, etc.) initialize wasabio like so:

// worker.ts
import { initialize } from "wasabio";
addEventListener("message", async ({ data }) => {
	initialize(data, { sync: true }); // sync as an option
});

From Existing Memory

Initialize wasabio on the first thread (usually the main thread) like so:

// main.ts
import { initialize } from "wasabio";
const cold = getSharedArrayBufferFromSomewhere();
const hot = await initialize(cold, { reboot: true });
// some time later
worker.postMessage(hot);

On other threads (workers, frames, etc.) initialize wasabio like so:

// worker.ts
import { initialize } from "wasabio";
addEventListener("message", async ({ data }) => {
	initialize(data, { reboot: false });
});

In this case, reboot signifies that the library is being initialized from cold storage and thread-local state should be reset.

Webpack Plugin

A Webpack plugin is provided to allow for seamless integration of wasabio into any project. The plugin currently supports generating a WASM memory that can be used to boot the library on the main thread with.

If you are not interested in using the Webpack plugin, you may opt out of its dependencies being installed by using npm install wasabio --omit=optional.