Function createEventsEmmiter

core/utils/eventManager.ts:25–104

(debug?: string)

const DEV_DEBUG_EVENTS = false;

export function createEventsEmmiter<
  EventsMap extends Record<string, unknown[]>
>(debug?: string): EventsEmmiter<EventsMap> {
  const subscribersMap = new Map<
    keyof EventsMap,
    Set<EventHandler<unknown[]>>
  >();

  function getHandlersForEvent<N extends keyof EventsMap>(
    name: N
  ): Set<EventHandler<EventsMap[N]>> {
    const existingSet = subscribersMap.get(name);

    if (existingSet) return existingSet;

    const newSet = new Set<EventHandler<unknown[]>>();

    subscribersMap.set(name, newSet);

    return newSet;
  }

  function on<N extends keyof EventsMap>(
    name: N,
    handler: EventHandler<EventsMap[N]>
  ) {
    const listeners = getHandlersForEvent(name);

    listeners.add(handler);

    return () => {
      listeners.delete(handler);
    };
  }

  function onOneOf<N extends keyof EventsMap>(
    names: N[],
    handler: EventHandler<EventsMap[N]>
  ) {
    const cleanup = createCleanupObject();

    for (const name of names) {
      cleanup.next = on(name, handler);
    }

    return () => {
      cleanup.clean();
    };
  }

  function hasListeners<N extends keyof EventsMap>(name: N) {
    return !!subscribersMap.get(name)?.size;
  }

  function emit<N extends keyof EventsMap>(name: N, ...data: EventsMap[N]) {
    if (IS_DEV && DEV_DEBUG_EVENTS && debug) {
      console.warn(`Event [${debug}]`, name, data);
    }