64 lines
2.9 KiB
JavaScript
64 lines
2.9 KiB
JavaScript
import getWeekYear from '../getWeekYear/index.js';
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import startOfWeek from '../startOfWeek/index.js';
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import toInteger from '../_lib/toInteger/index.js';
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/**
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* @name startOfWeekYear
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* @category Week-Numbering Year Helpers
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* @summary Return the start of a local week-numbering year for the given date.
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*
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* @description
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* Return the start of a local week-numbering year.
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* The exact calculation depends on the values of
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* `options.weekStartsOn` (which is the index of the first day of the week)
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* and `options.firstWeekContainsDate` (which is the day of January, which is always in
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* the first week of the week-numbering year)
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*
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* Week numbering: https://en.wikipedia.org/wiki/Week#Week_numbering
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*
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* ### v2.0.0 breaking changes:
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*
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* - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
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*
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* @param {Date|Number} date - the original date
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* @param {Object} [options] - an object with options.
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* @param {Locale} [options.locale=defaultLocale] - the locale object. See [Locale]{@link https://date-fns.org/docs/Locale}
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* @param {0|1|2|3|4|5|6} [options.weekStartsOn=0] - the index of the first day of the week (0 - Sunday)
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* @param {1|2|3|4|5|6|7} [options.firstWeekContainsDate=1] - the day of January, which is always in the first week of the year
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* @returns {Date} the start of a week-numbering year
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* @throws {TypeError} 1 argument required
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* @throws {RangeError} `options.weekStartsOn` must be between 0 and 6
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* @throws {RangeError} `options.firstWeekContainsDate` must be between 1 and 7
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*
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* @example
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* // The start of an a week-numbering year for 2 July 2005 with default settings:
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* var result = startOfWeekYear(new Date(2005, 6, 2))
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* //=> Sun Dec 26 2004 00:00:00
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*
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* @example
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* // The start of a week-numbering year for 2 July 2005
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* // if Monday is the first day of week
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* // and 4 January is always in the first week of the year:
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* var result = startOfWeekYear(new Date(2005, 6, 2), {
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* weekStartsOn: 1,
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* firstWeekContainsDate: 4
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* })
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* //=> Mon Jan 03 2005 00:00:00
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*/
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export default function startOfWeekYear(dirtyDate, dirtyOptions) {
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if (arguments.length < 1) {
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throw new TypeError('1 argument required, but only ' + arguments.length + ' present');
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}
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var options = dirtyOptions || {};
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var locale = options.locale;
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var localeFirstWeekContainsDate = locale && locale.options && locale.options.firstWeekContainsDate;
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var defaultFirstWeekContainsDate = localeFirstWeekContainsDate == null ? 1 : toInteger(localeFirstWeekContainsDate);
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var firstWeekContainsDate = options.firstWeekContainsDate == null ? defaultFirstWeekContainsDate : toInteger(options.firstWeekContainsDate);
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var year = getWeekYear(dirtyDate, dirtyOptions);
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var firstWeek = new Date(0);
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firstWeek.setFullYear(year, 0, firstWeekContainsDate);
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firstWeek.setHours(0, 0, 0, 0);
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var date = startOfWeek(firstWeek, dirtyOptions);
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return date;
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} |