54 lines
1.7 KiB
JavaScript
54 lines
1.7 KiB
JavaScript
import { getWeek } from "./getWeek.mjs";
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import { toDate } from "./toDate.mjs";
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/**
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* The {@link setWeek} function options.
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*/
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/**
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* @name setWeek
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* @category Week Helpers
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* @summary Set the local week to the given date.
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*
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* @description
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* Set the local week to the given date, saving the weekday number.
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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#The_ISO_week_date_system
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*
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* @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
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*
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* @param date - The date to be changed
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* @param week - The week of the new date
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* @param options - An object with options
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*
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* @returns The new date with the local week set
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*
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* @example
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* // Set the 1st week to 2 January 2005 with default options:
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* const result = setWeek(new Date(2005, 0, 2), 1)
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* //=> Sun Dec 26 2004 00:00:00
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*
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* @example
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* // Set the 1st week to 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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* const result = setWeek(new Date(2005, 0, 2), 1, {
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* weekStartsOn: 1,
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* firstWeekContainsDate: 4
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* })
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* //=> Sun Jan 4 2004 00:00:00
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*/
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export function setWeek(date, week, options) {
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const _date = toDate(date);
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const diff = getWeek(_date, options) - week;
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_date.setDate(_date.getDate() - diff * 7);
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return _date;
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}
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// Fallback for modularized imports:
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export default setWeek;
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