import getISOWeekYear from "../getISOWeekYear/index.js"; import startOfISOWeek from "../startOfISOWeek/index.js"; import requiredArgs from "../_lib/requiredArgs/index.js"; /** * @name endOfISOWeekYear * @category ISO Week-Numbering Year Helpers * @summary Return the end of an ISO week-numbering year for the given date. * * @description * Return the end 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 end of an ISO week-numbering year for 2 July 2005: * const result = endOfISOWeekYear(new Date(2005, 6, 2)) * //=> Sun Jan 01 2006 23:59:59.999 */ export default function endOfISOWeekYear(dirtyDate) { requiredArgs(1, arguments); var year = getISOWeekYear(dirtyDate); var fourthOfJanuaryOfNextYear = new Date(0); fourthOfJanuaryOfNextYear.setFullYear(year + 1, 0, 4); fourthOfJanuaryOfNextYear.setHours(0, 0, 0, 0); var date = startOfISOWeek(fourthOfJanuaryOfNextYear); date.setMilliseconds(date.getMilliseconds() - 1); return date; }