@moult/events

Generation-scoped, typed events for Moult plugins and hosts.

Installation

npm install @moult/events @moult/runtime

Requires Node.js 22 or newer.

Example

Subscriptions belong to a plugin scope. Disposing that generation removes its listeners automatically.

import { createEventBus } from '@moult/events';
import { createRuntime } from '@moult/runtime';

type AppEvents = {
  message: string;
  count: number;
};

const runtime = createRuntime();
const bus = createEventBus<AppEvents>('sync');

runtime.install({
  id: 'logger',
  version: '1.0.0',
  setup: (context) => {
    bus.on(context.scope, 'message', (message) => {
      console.log(message);
    });
  },
});

await runtime.start('logger');
bus.emit('message', 'hello');
await runtime.dispose(); // removes the logger subscription

Features

• Event names and payloads are checked by TypeScript.
• Synchronous and asynchronous delivery modes are supported.
• Subscriber failures are isolated and reported through an optional diagnostic callback.
• Asynchronous delivery preserves order per event key.
• Subscriptions are owned by the supplied Moult scope.
• eventBusFactory and eventBusCapability support host-provided buses.

This package is an event capability, not a second lifecycle system or a global application registry. Plugin replacement and disposal remain owned by @moult/runtime.

Public API

The package exports createEventBus, eventBusFactory, eventBusCapability, TypedEventCapability, EventBusFactory, EventMap, EventListener, EventDiagnostic, and DeliveryMode.

Status and documentation

Implemented and published. See the Moult repository, the adapter design, and the lifecycle guarantees.