thai_holidays 0.1.0

Pure-Dart Thai public-holiday calendar: fixed and movable Buddhist holidays, in-lieu days, special bridge days, and business-day helpers.

Changelog

0.1.0

Initial release.

Holidays

• Fixed-date Thai public holidays (New Year, Chakri, Songkran ×3, Labour Day, Coronation Day, royal birthdays, Chulalongkorn Day, memorial days, Constitution Day, New Year's Eve), with historical effective-year gating:
  • King Vajiralongkorn's Birthday (28 Jul) — from 2017.
  • King Bhumibol Memorial Day (13 Oct) — from 2017.
  • Coronation Day (4 May) — from 2019.
  • Queen Suthida's Birthday (3 Jun) — from 2019.
• Movable Buddhist holidays computed via thai_lunar: Makha Bucha, Visakha Bucha, Asalha Bucha, and Khao Phansa — including the athikamat (double-eighth-month) leap-year month shift.
• Cabinet-announced special ("bridge") holidays, seeded per year and current through 2026: 2023 (5 May, 31 Jul), 2024 (12 Apr, 30 Dec), 2025 (2 Jun, 11 Aug), 2026 (2 Jan). Sources: Thai cabinet resolutions (มติ ครม.) / PRD / ThaiPBS, cross-checked against the vacanza/holidays Thailand provider.
• Royal Ploughing Ceremony (วันพืชมงคล), a government-only holiday announced annually; seeded for 2024 (10 May), 2025 (9 May), 2026 (13 May). Sources: Nation Thailand, PublicHolidays.asia, Thaiger, Thailand NOW.
• Stack-aware in-lieu (substitution) days for holidays that fall on a weekend; an in-lieu day carries the id and bankHoliday flag of the holiday it observes.

API

• ThaiHolidayId enum + ThaiHoliday.id — stable, locale-independent identifier (avoids string-matching localized names).
• ThaiHoliday.bankHoliday (bool) — distinguishes the government public-holiday list from the Bank of Thailand bank-holiday list. false for Khao Phansa and the Royal Ploughing Ceremony (government holidays that banks do not observe).
• ThaiHoliday.name({bool thai = true}) — locale selector.
• holidayOn(DateTime) / holidaysOn(DateTime) — point queries.
• thaiHolidaysBetween(start, end, {includeSubstitution}) — range query across year boundaries.
• Business-day helpers: isBusinessDay, nextBusinessDay, addBusinessDays (supports negative n), and businessDaysBetween (half-open (a, b]).

Notes

• All dates are UTC, date-only.
• Supported range: accurate from ~2017 onward and current through 2026 for annually-announced entries (special bridge days and Royal Ploughing). Earlier years are approximate; future years are added as their dates are officially announced. See NOTICE.md.
• Lunar dates are computed via the thai_lunar engine (^0.1.0).