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