Function parseOffsetMinutes

src/time/localized-time.ts:188–194

(isoString: string)

function parseOffsetMinutes(isoString: string): number | null {
  if (isoString.endsWith('Z')) return 0;
  const match = isoString.match(/([+-])(\d{2}):(\d{2})$/);
  if (!match) return null;
  const sign = match[1] === '+' ? 1 : -1;
  return sign * (parseInt(match[2]) * 60 + parseInt(match[3]));
}

function getTimezoneGMT(date: Date, timezone?: string) {
  const fmt = getOffsetFormatter(timezone);