import { type QRL } from '@builder.io/qwik';
import type { FieldValue, Maybe } from '../types';
type Value<TFieldValue extends FieldValue> = Maybe<TFieldValue> | number[];
/**
 * Creates a validation function that checks the existence of an input.
 *
 * @param error The error message.
 *
 * @returns A validation function.
 */
export declare function required<TFieldValue extends FieldValue>(error: string): QRL<(value: Value<TFieldValue>) => string>;
export {};