export type AuthenticationState<User> = {
    currentUser?: User;
    isLoggedIn: boolean;
};
export type Subscriber<User> = (state: AuthenticationState<User>) => void;
export type AuthenticationService<User> = {
    login(user: User): void;
    logout(): void;
    subscribe(subscriber: Subscriber<User>): void;
    unsubscribe(subscriber: Subscriber<User>): void;
    getState: () => AuthenticationState<User>;
};
export declare function makeAuthenticationService<User>(): AuthenticationService<User>;
export declare function getDefaultState<User>(): AuthenticationState<User>;