export interface Action<T> extends Record<string, unknown> {
    type: T;
}
export type State = Record<string, unknown>;
export interface Props<S, T> {
    onStateChange?(typeAndChanges: unknown): void;
    stateReducer(state: S, actionAndChanges: Action<T> & {
        changes: Partial<S>;
    }): Partial<S>;
}
/**
 * This will perform a shallow merge of the given state object
 * with the state coming from props
 * (for the controlled component scenario)
 * This is used in state updater functions so they're referencing
 * the right state regardless of where it comes from.
 *
 * @param state The state of the component/hook.
 * @param props The props that may contain controlled values.
 * @returns The merged controlled state.
 */
export declare function getState<S extends State, P extends Partial<S> & Props<S, T>, T>(state: S, props?: P): S;