export declare function createPubSub<T = void>(): [
    publish: PublishFunction<T>,
    subscribe: SubscribeFunction<T>,
    getStoredData: GetFunctionPossiblyUndefined<T>
];
export declare function createPubSub<T>(storedData: T): [
    publish: PublishFunction<T>,
    subscribe: SubscribeFunction<T>,
    getStoredData: GetFunction<T>
];
export type SubscriptionHandler<T = void> = (data: T, previousData: T) => void;
export type PublishFunction<T = void> = (data: T) => void;
export type UnsubscribeFunction = () => void;
export type GetFunction<T> = () => T;
export type GetFunctionPossiblyUndefined<T = void> = () => T extends void ? undefined : T | undefined;
export type SubscribeFunction<T> = (handler: SubscriptionHandler<T>) => UnsubscribeFunction;