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- "use strict";
- var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault").default;
- Object.defineProperty(exports, "__esModule", {
- value: true
- });
- exports.default = getISOWeekYear;
- var _index = _interopRequireDefault(require("../toDate/index.js"));
- var _index2 = _interopRequireDefault(require("../startOfISOWeek/index.js"));
- var _index3 = _interopRequireDefault(require("../_lib/requiredArgs/index.js"));
- /**
- * @name getISOWeekYear
- * @category ISO Week-Numbering Year Helpers
- * @summary Get the ISO week-numbering year of the given date.
- *
- * @description
- * Get the ISO week-numbering year of the given date,
- * which always starts 3 days before the year's first Thursday.
- *
- * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
- *
- * @param {Date|Number} date - the given date
- * @returns {Number} the ISO week-numbering year
- * @throws {TypeError} 1 argument required
- *
- * @example
- * // Which ISO-week numbering year is 2 January 2005?
- * const result = getISOWeekYear(new Date(2005, 0, 2))
- * //=> 2004
- */
- function getISOWeekYear(dirtyDate) {
- (0, _index3.default)(1, arguments);
- var date = (0, _index.default)(dirtyDate);
- var year = date.getFullYear();
- var fourthOfJanuaryOfNextYear = new Date(0);
- fourthOfJanuaryOfNextYear.setFullYear(year + 1, 0, 4);
- fourthOfJanuaryOfNextYear.setHours(0, 0, 0, 0);
- var startOfNextYear = (0, _index2.default)(fourthOfJanuaryOfNextYear);
- var fourthOfJanuaryOfThisYear = new Date(0);
- fourthOfJanuaryOfThisYear.setFullYear(year, 0, 4);
- fourthOfJanuaryOfThisYear.setHours(0, 0, 0, 0);
- var startOfThisYear = (0, _index2.default)(fourthOfJanuaryOfThisYear);
- if (date.getTime() >= startOfNextYear.getTime()) {
- return year + 1;
- } else if (date.getTime() >= startOfThisYear.getTime()) {
- return year;
- } else {
- return year - 1;
- }
- }
- module.exports = exports.default;
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