60 lines
2 KiB
TypeScript
60 lines
2 KiB
TypeScript
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;
|