Vielzeug

Appearance

Standalone entry ​

Problem ​

You want the minimal setup to create a bus, emit a typed event, and receive it in a subscriber — the starting point before adding namespacing, disposal, or error handling.

Solution ​

ts
import { createBus } from '@vielzeug/eventit';

type WorkerEvents = {
  message: { id: string; body: string };
  stop: void;
};

const bus = createBus<WorkerEvents>();
bus.on('message', (payload) => console.log(payload.body));

Pitfalls ​

  • Calling emit() before any listener is registered silently discards the event. There is no event queue — register listeners before emitting.
  • on() returns an unsubscribe function. Ignoring the return value means the listener can only be removed with removeAllListeners().
  • The type parameter on createBus<T>() is compile-time only. Emitting an event name not in T is a TypeScript error but has no runtime guard.