Function weekGetter

packages/common/src/i18n/format_date.ts:534–553

(size: number, monthBased = false)

}

function weekGetter(size: number, monthBased = false): DateFormatter {
  return function (date: Date, locale: string) {
    let result;
    if (monthBased) {
      const nbDaysBefore1stDayOfMonth =
        new Date(date.getFullYear(), date.getMonth(), 1).getDay() - 1;
      const today = date.getDate();
      result = 1 + Math.floor((today + nbDaysBefore1stDayOfMonth) / 7);
    } else {
      const thisThurs = getThursdayThisIsoWeek(date);
      // Some days of a year are part of next year according to ISO 8601.
      // Compute the firstThurs from the year of this week's Thursday
      const firstThurs = getFirstThursdayOfYear(thisThurs.getFullYear());
      const diff = thisThurs.getTime() - firstThurs.getTime();
      result = 1 + Math.round(diff / 6.048e8); // 6.048e8 ms per week
    }

    return padNumber(result, size, getLocaleNumberSymbol(locale, NumberSymbol.MinusSign));
  };
}

/**
 * Returns a date formatter that provides the week-numbering year for the input date.