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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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/** * Calculate the week number based on configurable week start day. * * - ISO (monday): Week 1 is the week containing the first Thursday (has at least 4 days in the year) * - US (sunday): Week 1 is the week containing Jan 1 (first week has at least 1 day) * * @param dateStr ISO PlainDate string (e.g. "2024-03-15") * @param weekStartsOn optional: "monday" (default) or "sunday" * @returns Week number (1-53), or null on invalid input * * @example getWeekNumber("2024-01-01") // 1 * @example getWeekNumber("2024-01-08") // 2 * @example getWeekNumber("2024-12-31") // 1 * @example getWeekNumber("2024-01-01", "sunday") // 1 * @example getWeekNumber("invalid") // null */ export declare function getWeekNumber(dateStr: string, weekStartsOn?: "monday" | "sunday"): number | null;