Locales & utilities

Built-in locales

• en: Gregorian calendar, LTR, Sunday-first, weekends Sunday/Saturday, Western digits.
• fa: Jalali calendar, RTL, Monday-first, weekend Friday, Persian digits and strings.

Pass locale="fa" to switch, or provide a custom locale object.

Custom locale shape

Supply an object matching the internal contract:

const myLocale = {
  months: string[],
  weekDays: { name: string; short: string; isWeekend?: boolean }[],
  weekStartingIndex: number,
  getToday: ({ year, month, day }) => Day,
  toNativeDate: (day: Day) => Date,
  getMonthLength: (day: Day) => number,
  transformDigit: (digit: string | number) => string,
  nextMonth: string,
  previousMonth: string,
  openMonthSelector: string,
  closeMonthSelector: string,
  openYearSelector: string,
  closeYearSelector: string,
  from: string,
  to: string,
  defaultPlaceholder: string,
  digitSeparator: string,
  yearLetterSkip: number,
  isRtl: boolean,
};

Key points:

• toNativeDate should convert your calendar day to a native Date for comparisons.
• weekDays drives weekend highlighting and weekday headers; include isWeekend flags where needed.
• yearLetterSkip trims digits for locales that omit leading century characters when rendering.

Utility helpers

The package exports utils(locale). All functions honor the locale you pass (commonly 'en' or 'fa'):

• getToday(): today's date in the target calendar.
• getMonthName(month) / getMonthNumber(name).
• getMonthLength({ year, month }).
• getMonthFirstWeekday(date): aligns the grid with locale-specific week start.
• isBeforeDate(day1, day2): strict comparison using toNativeDate.
• checkDayInDayRange({ day, from, to }): detects whether a day falls inside a range.
• getLanguageDigits(value): formats numbers using locale digits.

Use these helpers for guardrails (e.g., minimumDate={utils(locale).getToday()}) so your constraints respect the same calendar logic as the UI.