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- import { getWeek } from "./getWeek.js";
- import { toDate } from "./toDate.js";
- /**
- * The {@link setWeek} function options.
- */
- /**
- * @name setWeek
- * @category Week Helpers
- * @summary Set the local week to the given date.
- *
- * @description
- * Set the local week to the given date, saving the weekday number.
- * The exact calculation depends on the values of
- * `options.weekStartsOn` (which is the index of the first day of the week)
- * and `options.firstWeekContainsDate` (which is the day of January, which is always in
- * the first week of the week-numbering year)
- *
- * Week numbering: https://en.wikipedia.org/wiki/Week#The_ISO_week_date_system
- *
- * @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).
- * @typeParam ResultDate - The result `Date` type, it is the type returned from the context function if it is passed, or inferred from the arguments.
- *
- * @param date - The date to be changed
- * @param week - The week of the new date
- * @param options - An object with options
- *
- * @returns The new date with the local week set
- *
- * @example
- * // Set the 1st week to 2 January 2005 with default options:
- * const result = setWeek(new Date(2005, 0, 2), 1)
- * //=> Sun Dec 26 2004 00:00:00
- *
- * @example
- * // Set the 1st week to 2 January 2005,
- * // if Monday is the first day of the week,
- * // and the first week of the year always contains 4 January:
- * const result = setWeek(new Date(2005, 0, 2), 1, {
- * weekStartsOn: 1,
- * firstWeekContainsDate: 4
- * })
- * //=> Sun Jan 4 2004 00:00:00
- */
- export function setWeek(date, week, options) {
- const date_ = toDate(date, options?.in);
- const diff = getWeek(date_, options) - week;
- date_.setDate(date_.getDate() - diff * 7);
- return toDate(date_, options?.in);
- }
- // Fallback for modularized imports:
- export default setWeek;
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