Function timezoneToOffset

packages/common/src/i18n/format_date.ts:889–895

(timezone: string, fallback: number)

}

function timezoneToOffset(timezone: string, fallback: number): number {
  // Support: IE 11 only, Edge 13-15+
  // IE/Edge do not "understand" colon (`:`) in timezone
  timezone = timezone.replace(/:/g, '');
  const requestedTimezoneOffset = Date.parse('Jan 01, 1970 00:00:00 ' + timezone) / 60000;
  return isNaN(requestedTimezoneOffset) ? fallback : requestedTimezoneOffset;
}

function addDateMinutes(date: Date, minutes: number) {
  date = new Date(date.getTime());