import dayjs from 'dayjs';
import { IDateProps, TDateValidatorResult } from '../_types';
export interface IStartOfProps {
    /**
     * Unit to be used.
     */
    unit: dayjs.OpUnitType;
    /**
     * TimeZone to be used.
     */
    timezone?: [tz: string, keepLocalTimes?: boolean];
}
/**
 * Set the date to the start of `unit`.
 */
export declare const setStartOf: (props: IStartOfProps & Omit<IDateProps, 'message'>) => TDateValidatorResult;