jlc-websocket

About

A lean and mean (not a lot of code bloat) WebSocket implementation written from scratch for Node.js in modern JavaScript. No dependencies and no third-party libraries. Why? Because I woke up one day and was ashamed that I hadn't written my own yet...

Should I use it? Well, it works on both the server side and the client side, has some nice features and is easy to use! And it passes the Autobahn WebSocket protocol test suite!

An example showing both server and client usage:

import {WebSocket} from 'jlc-websocket'
import * as http from 'node:http'

const server = true

if (server) {
  http.createServer((request, response) => {
    response.writeHead(200)
    response.end('Hello world!')
  })
  .on('upgrade', (request) => {
    wsConnectionHandler(new WebSocket(request))
  })
  .listen(8080)
} else { // if client
  wsConnectionHandler(new WebSocket('ws://localhost:8080'))
}

function wsConnectionHandler(ws) {
  ws.on('open', () => {
    console.log('New connection to:', ws.socket.remoteAddress)
    ws.send('Hello!')
  })
  ws.on('message', ({data, isFinal}) => {
    console.log(data)
  })
}

Current features

• Server and client implementation.
• Compression support (the permessage-deflate extension).
• Possibility to send and receive Node.js streams.
• Possibility to receive message fragments as they come.
• UTF-8 verification using fast native functions.
• Possibility to manually ping the connection with a custom payload.

Todo list

• Configurable automatic reconnection (client side only).

Documentation

The API is compatible with the standard Web API described at MDN: https://developer.mozilla.org/en-US/docs/Web/API/WebSocket

I will write further documentation later.