app/node_modules/date-fns/esm/lastDayOfISOWeekYear/index.js

import getISOWeekYear from "../getISOWeekYear/index.js";
import startOfISOWeek from "../startOfISOWeek/index.js";
import requiredArgs from "../_lib/requiredArgs/index.js";
/**
 * @name lastDayOfISOWeekYear
 * @category ISO Week-Numbering Year Helpers
 * @summary Return the last day of an ISO week-numbering year for the given date.
 *
 * @description
 * Return the last day of an ISO week-numbering year,
 * which always starts 3 days before the year's first Thursday.
 * The result will be in the local timezone.
 *
 * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
 *
 * @param {Date|Number} date - the original date
 * @returns {Date} the end of an ISO week-numbering year
 * @throws {TypeError} 1 argument required
 *
 * @example
 * // The last day of an ISO week-numbering year for 2 July 2005:
 * const result = lastDayOfISOWeekYear(new Date(2005, 6, 2))
 * //=> Sun Jan 01 2006 00:00:00
 */
export default function lastDayOfISOWeekYear(dirtyDate) {
  requiredArgs(1, arguments);
  var year = getISOWeekYear(dirtyDate);
  var fourthOfJanuary = new Date(0);
  fourthOfJanuary.setFullYear(year + 1, 0, 4);
  fourthOfJanuary.setHours(0, 0, 0, 0);
  var date = startOfISOWeek(fourthOfJanuary);
  date.setDate(date.getDate() - 1);
  return date;
}