/**
 * IGradings are provided in a list to the Duration.
 */
export interface IGrading {
    unit: string | ((x: number) => string);
    milliseconds: number;
}
export declare const millisecond: IGrading;
export declare const second: IGrading;
export declare const minute: IGrading;
export declare const hour: IGrading;
export declare const day: IGrading;
/**
 * ISegments are the count of how many units are in each grading, returned
 * from the Duration's getSegments call.
 */
export interface ISegment {
    unit: string;
    count: number;
}
export declare class Duration {
    private _duration;
    private _grading;
    private _separator;
    constructor(_duration: number);
    /**
     * Sets the grading used for handling durations.
     */
    grading(grading: IGrading[]): this;
    /**
     * Sets the separator used between durations.
     */
    separator(separator: string): this;
    /**
     * Returns the duration formatted into the given number of segments.
     */
    segments(max?: number): string;
    /**
     * Converts the duration to a string.
     */
    toString(segments?: number): string;
}
export declare function fmt(duration: number): Duration;