@flare-engine/events

Type-safe event primitives — EventEmitter<EventMap> for keyed events and Signal<T> for single-payload broadcast. Both support once(), deferred-remove during emit(), and zero-alloc Unsubscribe returns.

Install

bun add @flare-engine/events

Usage

import { EventEmitter, Signal } from '@flare-engine/events';

type GameEvents = { 'enemy-killed': (e: { id: number; score: number }) => void };
const bus = new EventEmitter<GameEvents>();
const off = bus.on('enemy-killed', (e) => console.log(e.score));

const onHit = new Signal<number>();
onHit.add((dmg) => console.log(dmg));
onHit.emit(10);

Emit semantics

emit() iterates the handler set live (no per-emit snapshot — this is a hot path):

• A handler added during an emit runs in that same emit.
• A handler removed during an emit still runs for that emit (and any nested emit); the removal takes effect once the outermost emit completes. Exception: a once() handler fires at most once, even under a nested emit.
• emit() is re-entrant (a handler may call emit() again) and throw-safe: a throwing handler propagates to the caller but never wedges deferred removal.

See API spec.

License

Apache-2.0