Function startOfWeekYear

pkgs/core/src/startOfWeekYear/index.ts:60–81

(
  date: DateArg<DateType>,
  options?: StartOfWeekYearOptions<ResultDate>,
)

 * //=> Mon Jan 03 2005 00:00:00
 */
export function startOfWeekYear<
  DateType extends Date,
  ResultDate extends Date = DateType,
>(
  date: DateArg<DateType>,
  options?: StartOfWeekYearOptions<ResultDate>,
): ResultDate {
  const defaultOptions = getDefaultOptions();
  const firstWeekContainsDate =
    options?.firstWeekContainsDate ??
    options?.locale?.options?.firstWeekContainsDate ??
    defaultOptions.firstWeekContainsDate ??
    defaultOptions.locale?.options?.firstWeekContainsDate ??
    1;

  const year = getWeekYear(date, options);
  const firstWeek = constructFrom(options?.in || date, 0);
  firstWeek.setFullYear(year, 0, firstWeekContainsDate);
  firstWeek.setHours(0, 0, 0, 0);
  const _date = startOfWeek(firstWeek, options);
  return _date;
}