import { DurationInput } from './types';
interface ToStringOptions {
    decimalDelimiter: string;
}
/**
 * Stringify a duration into an ISO duration string.
 *
 * @example
 * toString({ years: 1, hours: 6 }) // 'P1YT6H'
 * toString(6000) // 'PT6S'
 */
export declare const toString: (duration: DurationInput, options?: Partial<ToStringOptions>) => string;
export {};