export type StorageEventListener<T> = (event: T) => void;

export class StorageEvent<TMessage> {
    listeners = new Set<StorageEventListener<TMessage>>();

    get length(): number {
        return this.listeners.size;
    }

    dispatch(message: TMessage): void {
        this.listeners.forEach(callback => callback(message));
    }

    addListener(listener: StorageEventListener<TMessage>): void {
        this.listeners.add(listener);
    }

    removeListener(listener: StorageEventListener<TMessage>): void {
        this.listeners.delete(listener);
    }
}