59 lines
2.5 KiB
JavaScript
59 lines
2.5 KiB
JavaScript
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import startOfWeek from '../startOfWeek/index.js';
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import startOfWeekYear from '../startOfWeekYear/index.js';
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import toDate from '../toDate/index.js';
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var MILLISECONDS_IN_WEEK = 604800000;
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/**
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* @name getWeek
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* @category Week Helpers
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* @summary Get the local week index of the given date.
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*
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* @description
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* Get the local week index of the given date.
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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 given 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 {Number} the week
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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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* // Which week of the local week numbering year is 2 January 2005 with default options?
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* var result = getISOWeek(new Date(2005, 0, 2))
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* //=> 2
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*
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* // Which week of the local week numbering year is 2 January 2005,
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* // if Monday is the first day of the week,
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* // and the first week of the year always contains 4 January?
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* var result = getISOWeek(new Date(2005, 0, 2), {
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* weekStartsOn: 1,
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* firstWeekContainsDate: 4
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* })
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* //=> 53
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*/
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export default function getWeek(dirtyDate, options) {
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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 date = toDate(dirtyDate);
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var diff = startOfWeek(date, options).getTime() - startOfWeekYear(date, options).getTime(); // Round the number of days to the nearest integer
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// because the number of milliseconds in a week is not constant
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// (e.g. it's different in the week of the daylight saving time clock shift)
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return Math.round(diff / MILLISECONDS_IN_WEEK) + 1;
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}
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