export declare class PHXDateHelpers {
    calculateDateDifference(startDate: Date, endDate: Date, valueReturnIfNotValidDate?: number): number;
    dateStrToDate(date: string): string;
    dateStrToDateTime(date: string, isTimeFirst?: boolean): string;
    formatDateHyphen(timestamp: any): string;
    calculateRemainingTime(startTimeString: any, endTimeString: any): string;
    dateStrToTime(dateStr: string): string;
    isPastDate(compareDate: string): boolean;
}