import { Signal } from "../signals/signal.js";
export declare function maybe<X, R>(x: X, fn: (x: X) => R): R | undefined;
export declare function whereby<X, R>(x: X | undefined | null | Signal<X | undefined | null>, fn: (x: X) => R): R | undefined;
/** @deprecated renamed to `whereby` */
export declare const wherefor: typeof whereby;