Class Event

packages/clay/src/utils/event.ts:10–42

 * the callback as an arrow function.
 */
export class Event<T> {
  /**
   * Add a callback to this event instance.
   * @param handler - the callback to be added to this event.
   */
  add(handler: T extends void ? { (): void } : { (data: T): void }): void {
    this.handlers.push(handler);
  }

  /**
   * Removes a callback from this event instance.
   * @param handler - the callback to be removed from this event.
   */
  remove(handler: T extends void ? { (): void } : { (data: T): void }): void {
    this.handlers = this.handlers.filter((h) => h !== handler);
  }

  /** Triggers all the callbacks assigned to this event. */
  trigger = async (data?: T) => {
    const handlers = this.handlers.slice(0);
    for (const handler of handlers) {
      await handler(data as any);
    }
  };

  /** Gets rid of all the suscribed events. */
  reset() {
    this.handlers.length = 0;
  }

  private handlers: (T extends void ? { (): void } : { (data: T): void })[] =
    [];
}