@bimetal/broker-broadcast

BroadcastChannel adapter for @bimetal/broker — cross-tab, same-origin pub/sub. Every browser tab/worker that opens a broker on the same channel name forms one bus. Zero external dependencies; a thin wrapper over createPortBroker.

Installation

npm install @bimetal/broker-broadcast @bimetal/broker

Usage

import { createBroadcastBroker } from '@bimetal/broker-broadcast';

const broker = createBroadcastBroker({ channel: 'bimetal' });

broker.subscribe('calendar.created', (msg, topic) => {
  // fires in THIS tab and every other tab on the 'bimetal' channel
});

await broker.publish('calendar.created', { id: '1' });

What's Inside

• createBroadcastBroker(options) → a full Broker<TMessage> (plus close()/flush()).
  • channel — the BroadcastChannel name; the shared bus identity.
  • factory? — override channel creation (default new BroadcastChannel(name)); inject a fake in tests.
  • onError? — handler-error sink (default console.error).
• BroadcastBrokerOptions, BroadcastBroker<TMessage>, BroadcastChannelLike

Adapter properties

• Capabilities: { patterns: true, replay: false, ordering: 'none' }. Pattern routing (*/#) is done locally on the receiving side. Cross-tab with multiple publishers has no shared clock → no ordering promise.
• Local + remote in one publish. A BroadcastChannel never echoes to its own sender, so the relay fans a publish out to local subscribers AND posts it to the channel — every tab including the originator hears it, exactly once.
• Structured clone. Messages must be structured-cloneable (DomainEvents are). A non-cloneable payload throws at postMessage.
• Foreign messages ignored. Only broker-tagged envelopes are delivered; other traffic on the channel is skipped.
• close() detaches the listener and closes the channel.

License

PolyForm Noncommercial License 1.0.0