@carlosv2/adapter-node-ws

Adapter for SvelteKit apps that generates a standalone Node server with support for WebSockets.

This package uses the ws library to provide the websockets functionality.

Disclaimer

This project has taken a fair amount of shorcuts due to SvelteKit not being ready yet and the author having the need to deliver code. Nevertheless, it should provide a convenient package to build WebSockets on top.

I can't guarantee it will suite the needs of everybody (actually, I can most likely guarantee the oposite) but I'm happy to, given a PR, review and comment on potential improvemnts (there is lot of room for improvement!).

Docs

This adapter comes with support for both DEV and PROD.

Each environment can be configured individually.

Development

Unfortunately, I couldn't find another way of doing this than changing the original HMR port from Vite. This, however, should not affect the functionality but it does introduce a minimal configuration. In your vite.config.ts, you need to add:

const config: UserConfig = {
  server: {
    hmr: { port: <any other than your server port> }
  }
};

In addition to this change, you also need to add the plugin to inject the WebSocket into the same file:

import WebSockets from "@carlosv2/adapter-node-ws/plugin";

const config: UserConfig = {
  plugins: [WebSockets()],
};

Production

Simply replace your adapter in svelte.config.js with this one:

import adapter from "@carlosv2/adapter-node-ws/adapter";

/** @type {import('@sveltejs/kit').Config} */
const config = {
  kit: {
    adapter: adapter({
      // adapter options go here
    }),
  },
};

Since this adapter is based on @sveltejs/adapter-node, any configuration for that adapter is still valid and applicable to this one.

How to use

Have you configured the required environments? Good, then the only thing left is to build WebSockety code. For this, quite simply export a function named handleWs to your hooks.server.ts file:

import type { WebSocketServer } from "ws";

export const handleWs = (wss: WebSocketServer) => {
  wss.on("connection", (ws) => {
    ws.send("Hello World!");
  });
};

License

MIT