export declare function hourKey(ts: number): string;
export declare function dayKey(ts: number): string;
export declare function dayOfHourKey(hour: string): string;
export declare function monthOfHourKey(hour: string): string;
export declare function hourStartOf(hour: string): number;
export declare function dayStartOf(date: string): number;
export declare function startOfUtcDay(ts: number): number;