export function todayKeyInTz(tz: string, now: Date = new Date()): string {
  const fmt = new Intl.DateTimeFormat("en-CA", {
    timeZone: tz,
    year: "numeric",
    month: "2-digit",
    day: "2-digit",
  });
  return fmt.format(now);
}

export function addDaysToKey(yyyyMmDd: string, days: number): string {
  const d = new Date(`${yyyyMmDd}T00:00:00Z`);
  d.setUTCDate(d.getUTCDate() + days);
  return d.toISOString().slice(0, 10);
}