import { TReferenceProps } from '../../..';
import { IStringProps, TStringValidatorResult } from '../_types';
export interface IIsRequiredProps {
}
/**
 * Check if the `string` is defined. Will also reject `''`.
 */
export declare const isRequired: (props?: TReferenceProps<IIsRequiredProps> & IStringProps) => TStringValidatorResult;