method Temporal.CalendarProtocol.dateAdd CalendarProtocol.dateAdd(date: Temporal.PlainDate | PlainDateLike | string,duration: Temporal.Duration | DurationLike | string,options?: ArithmeticOptions,): Temporal.PlainDate Parameters date: Temporal.PlainDate | PlainDateLike | string duration: Temporal.Duration | DurationLike | string optional options: ArithmeticOptions Return Type Temporal.PlainDate