Function isWeekend

packages/@internationalized/date/src/queries.ts:395–410

(date: DateValue, locale: string)

/** Returns whether the given date is on a weekend in the given locale. */
export function isWeekend(date: DateValue, locale: string): boolean {
  let julian = date.calendar.toJulianDay(date);

  // If julian is negative, then julian % 7 will be negative, so we adjust
  // accordingly.  Julian day 0 is Monday.
  let dayOfWeek = Math.ceil(julian + 1) % 7;
  if (dayOfWeek < 0) {
    dayOfWeek += 7;
  }

  let region = getRegion(locale);
  // Use Intl.Locale for this once weekInfo is supported.
  // https://github.com/tc39/proposal-intl-locale-info
  let [start, end] = WEEKEND_DATA[region!] || [6, 0];
  return dayOfWeek === start || dayOfWeek === end;
}

/** Returns whether the given date is on a weekday in the given locale. */
export function isWeekday(date: DateValue, locale: string): boolean {