export type TimeAgoFormatter<T = number> = (value: T, isPast: boolean) => string;
export type TimeAgoUnitNamesDefault = 'second' | 'minute' | 'hour' | 'day' | 'week' | 'month' | 'year';
export type TimeAgeFullDateFormatter = (date: Date) => string;
export type TimeAgoMessagesBuiltIn = {
    justNow: string;
    past: string | TimeAgoFormatter<string>;
    future: string | TimeAgoFormatter<string>;
    invalid: string;
};
export type TimeAgoMessages<UnitNames extends string = TimeAgoUnitNamesDefault> = TimeAgoMessagesBuiltIn & Record<UnitNames, string | TimeAgoFormatter<number>>;
export type FormatTimeAgoOptions<UnitNames extends string = TimeAgoUnitNamesDefault> = {
    /**
     * Maximum unit (of diff in milliseconds) to display the full date instead of relative
     *
     * @defaultValue undefined
     */
    max?: UnitNames | number;
    /**
     * Formatter for full date
     */
    fullDateFormatter?: TimeAgeFullDateFormatter;
    /**
     * Messages for formatting the string
     */
    messages?: TimeAgoMessages<UnitNames>;
    /**
     * Minimum display time unit (default is minute)
     *
     * @defaultValue false
     */
    showSecond?: boolean;
    /**
     * Rounding method to apply.
     *
     * @defaultValue 'round'
     */
    rounding?: 'round' | 'ceil' | 'floor' | number;
    /**
     * Custom units
     */
    units?: TimeAgoUnit<UnitNames>[];
};
export type TimeAgoUnit<Unit extends string = TimeAgoUnitNamesDefault> = {
    max: number;
    value: number;
    name: Unit;
};
export declare const DEFAULT_MESSAGES: TimeAgoMessages<TimeAgoUnitNamesDefault>;
export declare function formatTimeAgo<UnitNames extends string = TimeAgoUnitNamesDefault>(from: Date, options?: FormatTimeAgoOptions<UnitNames>, now?: Date | number): string;