Eventbus reference

Local serial/parallel delivery and optional cross-context broadcasting.

Installation and runtime

pnpm add @ahoo-wang/fetcher-eventbus @ahoo-wang/fetcher

Version 5.0.0 declares Node >=18.20.8 for consumers. Repository development has a separate Node >=20.20.2 / pnpm 10.34.5 requirement. Browser/runtime APIs used by a feature must also exist; the engine range is not a promise that every Web API (for example Response.bytes) is available.

Choose an entry point

Use SerialTypedEventBus for ordered handlers within one emission, ParallelTypedEventBus for independent handlers, and EventBus for several named event families. Add BroadcastTypedEventBus only when another context needs notifications; its transport does not acknowledge remote processing.

Choose a topic

Topic	Use it for
Events and local delivery	Choose a typed bus for one payload type, or EventBus<Events> to route multiple named event types. Neither implementation persists events, retries delivery, or turns a handler failure into a failed business transaction.
Broadcast buses and messengers	BroadcastTypedEventBus<EVENT> decorates a local TypedEventBus<EVENT> with cross-context delivery. The transport is notification-only: there is no acknowledgment, remote completion wait, replay, or delivery guarantee.

Minimal complete example

import { EventBus, SerialTypedEventBus } from '@ahoo-wang/fetcher-eventbus';

type Events = { saved: { id: string }; signedOut: undefined };
const bus = new EventBus<Events>(
  type => new SerialTypedEventBus<unknown>(type),
);
const received: string[] = [];
bus.on('saved', {
  name: 'audit',
  order: 0,
  once: true,
  handle: event => {
    received.push(event.id);
  },
});
await bus.emit('saved', { id: '1' });
await bus.emit('saved', { id: '2' });
console.assert(received.join(',') === '1');
bus.destroy();

Complete public symbol index