import Validator, { ValidatorMessage } from './Validator';
/**
 * A wrapper which adds emptiness to validator allowed values.
 */
export default class AllowEmpty<T extends import('intl-ts').Messages, P extends any[]> implements Validator<T, P> {
    private validator;
    readonly params: P;
    constructor(validator: Validator<T, P>);
    validate(value: string): ValidatorMessage<T, P> | undefined;
}
/**
 * Wrap all validators of the given array into an {@link #AllowEmpty}.
 *
 * @param validators - The validators to wrap.
 * @returns The same validator which will allow an empty value.
 */
export declare function allowEmpty(validators: Validator[]): Validator[];