@burglekitt/gmt/dist/plain/calculate/getWeeksInLocaleWeekYear.d.ts

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

/**
 * Return the number of weeks (52 or 53) in the locale week-numbering year
 * containing `value`, using `locale`'s first day of week and
 * minimal-days-in-first-week.
 *
 * - `getWeeksInYear`'s locale-relative counterpart — that function uses
 *   the fixed ISO rule, this one uses `locale`'s week-numbering rule
 *   (via `Intl.Locale.prototype.weekInfo`), and the two can disagree on
 *   the same date.
 * - Computed as the number of calendar days between the locale
 *   week-year's start and the next week-year's start, divided by 7 —
 *   always a whole number, since both bounds fall on the locale's first
 *   day of week.
 * - Returns null if `value` or `locale` is invalid.
 *
 * @param value ISO PlainDate string
 * @param locale BCP 47 locale tag (e.g. "en-US", "fr-FR")
 * @returns 52 or 53, or null on invalid input
 *
 * @example getWeeksInLocaleWeekYear("2024-06-15", "en-US") // 52
 * @example getWeeksInLocaleWeekYear("2020-06-15", "de-DE") // 53
 * @example getWeeksInLocaleWeekYear("invalid", "en-US") // null
 */
export declare function getWeeksInLocaleWeekYear(value: string, locale: string): number | null;