/**
* Date formatting utilities using date-fns-tz for timezone-aware formatting
*/
import { formatInTimeZone, fromZonedTime } from 'date-fns-tz';
/**
* Format a date to ISO 8601 with timezone offset.
* Returns format: YYYY-MM-DDTHH:mm:ss±HH:mm
*
* @param date - Date object, ISO string, or timestamp
* @param timezone - IANA timezone (e.g., 'America/New_York', 'Europe/London')
* @returns ISO 8601 string with timezone offset
*
* @example
* formatToISO8601WithTimezone('2024-12-29T10:30:00Z', 'America/New_York')
* // Returns: '2024-12-29T05:30:00-05:00'
*/
export function formatToISO8601WithTimezone(date: Date | string | number, timezone: string): string {
return formatInTimeZone(date, timezone, "yyyy-MM-dd'T'HH:mm:ssXXX");
}
/**
* Get the current time in ISO 8601 format with timezone offset.
* Returns format: YYYY-MM-DDTHH:mm:ss±HH:mm
*
* @param timezone - IANA timezone (e.g., 'America/New_York', 'Europe/London')
* @returns Current time as ISO 8601 string with timezone offset
*/
export function getCurrentTimeInTimezone(timezone: string): string {
return formatToISO8601WithTimezone(new Date(), timezone);
}
/**
* Convert a local datetime string (without timezone) to ISO 8601 with timezone offset.
* Assumes the input string is already in the specified timezone.
*
* @param localDateTimeString - Local datetime string (e.g., '2024-12-29T14:30:00')
* @param timezone - IANA timezone the string is in
* @returns ISO 8601 string with timezone offset
*
* @example
* localStringToISO8601WithTimezone('2024-12-29T14:30:00', 'America/New_York')
* // Returns: '2024-12-29T14:30:00-05:00'
*/
export function localStringToISO8601WithTimezone(localDateTimeString: string, timezone: string): string {
// fromZonedTime interprets the input as local time in the specified timezone
// and returns the equivalent UTC Date object
const utcDate = fromZonedTime(localDateTimeString, timezone);
// Then format that UTC time back in the target timezone with offset
return formatToISO8601WithTimezone(utcDate, timezone);
}
