export declare type UpdateFn<S> = (state: S) => S;
export declare type Subscriber<S> = (state: S) => void;
export declare type Cb<S = unknown> = (newV: S, oldV: S, source?: unknown) => void;
export declare type Unsubscribe = () => void;
export interface ITangleContext<S> {
    stateOf<K extends keyof S>(key: K): S[K];
    subscribe<K extends keyof S>(key: K, cb: Cb<S[K]>): Unsubscribe;
    /**
     * Update the given
     * @param key
     * @param source
     */
    update<K extends keyof S, C = unknown>(key: K, newV: S[K], caller?: C): void;
}
export declare type KeyOf<S> = keyof S;