export type Listener<Type extends string, P = any> = {
    /** Event type the listener is waiting for. */
    eventType: Type;
    /** Function to call on event. */
    callback: Callback<void> | Callback<P> | AsyncCallback<void> | AsyncCallback<P>;
    /** Unique identifier of the context in which the listener was created. */
    scopeKey?: string;
    /**
     * Unique identifier of the event group.
     *
     * Note: It is used if `listenForEvents` has been called with an array of event types.
     */
    eventGroupId?: string;
    /** Boolean indicating whether the listener should be called only once if the event occurs. */
    shouldBeCalledOnce?: boolean;
    /** Boolean indicating whether the listener has been called at least once. */
    hasBeenCalled?: boolean;
};
export type Callback<P = void, R = void> = P extends void ? () => R : P extends [infer A, ...infer Rest] ? (...args: [A, ...Rest]) => R : P extends [] ? (...args: P[]) => R : (arg: P) => R;
export type AsyncCallback<P = void, R = Promise<void>> = Callback<P, R>;
export type Extend<Source, Target> = Exclude<Source, keyof Target> & Target;
export type CleanupFunction = Callback;