@priemskiyyy/simulcast-broadcast-channel

BroadcastChannel adapter for simulcast: same-origin realtime between tabs, workers, and tests, with no server.

Installation

pnpm add @priemskiyyy/simulcast @priemskiyyy/simulcast-broadcast-channel

Create a client

import { RealtimeClient } from "@priemskiyyy/simulcast";
import { broadcastChannel } from "@priemskiyyy/simulcast-broadcast-channel";

const realtime = new RealtimeClient({
  adapter: broadcastChannel({ prefix: "app:" }),
});

const disconnect = realtime.connect();
const unsubscribe = realtime.channel("rooms:demo").subscribe((publication) => {
  console.log(publication.data);
});

const publisher = new BroadcastChannel("app:rooms:demo");
publisher.postMessage({ text: "hello" });

// When the application is done listening:
// unsubscribe();
// disconnect();
// publisher.close();

Behavior

A channel is a BroadcastChannel name, optionally prefixed. Every posted message becomes a publication with the structured-cloned payload in data and the MessageEvent in native. A session is always connected and channels are subscribed as soon as they are demanded. It is a convenient way to keep several tabs in sync, to demo hooks without a backend, and to drive integration tests through the same code path a provider would.

BroadcastChannel sends to other instances with the same name, not back to the sending instance. All participating tabs must share an origin. Its connection-level native value is null; use your own BroadcastChannel instance to publish and close that instance when finished.

Guides

• Installation and framework setup
• Adapter configuration and state mappings
• Connection sessions
• Testing consumers without a provider

License

MIT