/**
 * 常量
 */
export declare function getStartDate(date: Date, before: number): number;
export declare function getEndDate(date: Date, before: number): number;
export declare function getDateString(millisecond: number): string;
export declare function getMonthDays(currentDate: Date): number;
export declare function getMonthPeriod(currentDate: Date, n: number): string;
export declare function getWeeKPeriod(currentDate: Date, t: number): string;