export type Subscriber<T> = (nextValue: T, previousValue: T) => void;
export type Getter<T> = () => T;
export type ValueOrGetter<T> = T | Getter<T>;
export type Updater<T> = (previousValue: T) => T;
export type ValueOrUpdater<T> = T | Updater<T>;
export type SharedState<T> = {
    get: () => T;
    set: (valueOrUpdater: ValueOrUpdater<T>) => void;
    subscribe: (handler: Subscriber<T>) => void;
    unsubscribe: (handler: Subscriber<T>) => void;
};
export type DerivedSharedStateGetter<T> = (stateValueGetter: <T>(sharedState: SharedState<T>) => T) => T;
export type DerivedSharedStateSetter<T> = (value: T) => void;