export declare class Dates {
  private static months;
  private static months_short;
  private static months_narrow;
  private static weekdays;
  private static weekdays_short;
  private static weekdays_narrow;
  private static initialized;
  static init(): void;
  static isValid(date: Date): boolean;
  static format(date: Date, formatStr?: string): string;
  static parse(value: string, formatStr?: string): Date;
  static formatIsoWeekDay(weekDayNumber: number, width?: 'long' | 'short' | 'narrow'): string;
  static formatWeekDay(weekDayNumber: number, width?: 'long' | 'short' | 'narrow'): string;
  static formatWeekdays(width?: 'long' | 'short' | 'narrow'): string[];
  static formatMonth(monthNumber: number, width?: 'long' | 'short' | 'narrow'): string;
  static formatMonths(width?: 'long' | 'short' | 'narrow'): string[];
  static getWeekStart(date?: Date): Date;
  static getWeek(date?: Date): number;
  private static getLocale;
}