export type TimerCallback = () => void | boolean | Promise<void | boolean>;
export interface Chrono {
    lastMeasure?: ChronoMeasure;
    allMeasures: ChronoMeasure[];
    start(label: string, printTitle?: string): void;
    start_withLimit(limit_ms: number, label: string, printTitle?: string): void;
    end(): void;
    onMeasureDone(handler: null | ((measure: ChronoMeasure) => void)): void;
}
export interface ChronoMeasure {
    label?: string;
    title?: string;
    logIfMoreThan_ms?: number;
    startTime_ms: number;
    endTime_ms: number;
    elapsedTime_ms: number;
    elapsedTime_sec: string;
}
export declare const ONE_SECOND = 1000;
export declare const ONE_MINUTE: number;
export declare const ONE_HOUR: number;
export declare const ONE_DAY: number;
export declare function newInterval(durationInMs: number, callback: TimerCallback): void;
export declare function deferred(callback: () => void): void;
export declare function tick(timeInMs: number): Promise<void>;
export declare const sleep: typeof tick;
export declare const pause: typeof tick;
export declare function chrono(mustSaveMeasures: boolean): Chrono;