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@burglekitt/gmt

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Temporal-based date and time utilities with timezone support and polyfill integration

github.com/burglekitt/gmt

burglekitt/gmt

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/** * Return the number of ISO weeks (52 or 53) in the ISO week-numbering year * containing `value`. * * - Uses `value`'s ISO week-numbering year (`Temporal.PlainDate.yearOfWeek`), * not its calendar year — late-December/early-January dates can belong to * a different ISO week-year than their calendar year (e.g. 2021-01-01 is * ISO week-year 2020's week 53). * - December 28 always falls in the ISO week-numbering year's final week * (ISO week 1 always contains Jan 4, so Dec 28 — exactly 52 weeks after — * is always in the last week), so its `weekOfYear` reports the year's * total week count. * - Returns null on invalid input. * * @param value ISO PlainDate string * @returns 52 or 53, or null on invalid input * * @example getWeeksInYear("2024-06-15") // 52 * @example getWeeksInYear("2020-06-15") // 53 * @example getWeeksInYear("2021-01-01") // 53 (belongs to ISO week-year 2020) * @example getWeeksInYear("invalid") // null */ export declare function getWeeksInYear(value: string): number | null;