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- import type {
- ContextOptions,
- DateArg,
- FirstWeekContainsDateOptions,
- LocalizedOptions,
- WeekOptions,
- } from "./types.js";
- /**
- * The {@link startOfWeekYear} function options.
- */
- export interface StartOfWeekYearOptions<DateType extends Date = Date>
- extends LocalizedOptions<"options">,
- FirstWeekContainsDateOptions,
- WeekOptions,
- ContextOptions<DateType> {}
- /**
- * @name startOfWeekYear
- * @category Week-Numbering Year Helpers
- * @summary Return the start of a local week-numbering year for the given date.
- *
- * @description
- * Return the start of a local week-numbering year.
- * 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.
- *
- * @param date - The original date
- * @param options - An object with options
- *
- * @returns The start of a week-numbering year
- *
- * @example
- * // The start of an a week-numbering year for 2 July 2005 with default settings:
- * const result = startOfWeekYear(new Date(2005, 6, 2))
- * //=> Sun Dec 26 2004 00:00:00
- *
- * @example
- * // The start of a week-numbering year for 2 July 2005
- * // if Monday is the first day of week
- * // and 4 January is always in the first week of the year:
- * const result = startOfWeekYear(new Date(2005, 6, 2), {
- * weekStartsOn: 1,
- * firstWeekContainsDate: 4
- * })
- * //=> Mon Jan 03 2005 00:00:00
- */
- export declare function startOfWeekYear<
- DateType extends Date,
- ResultDate extends Date = DateType,
- >(
- date: DateArg<DateType>,
- options?: StartOfWeekYearOptions<ResultDate>,
- ): ResultDate;
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