holiday-de.js

(function (exports) {
  'use strict';

  // calculate the date of easter sunday for the given year
  var cache = {};
  function calculateEasterSunday(year) {
    if (!cache[year]) {
      var a = year % 19;
      var b = Math.floor(year / 100);
      var c = year % 100;
      var d = Math.floor(b / 4);
      var e = b % 4;
      var f = Math.floor((b + 8) / 25);
      var g = Math.floor((b - f + 1) / 3);
      var h = (19 * a + b - d - g + 15) % 30;
      var i = Math.floor(c / 4);
      var k = c % 4;
      var l = (32 + 2 * e + 2 * i - h - k) % 7;
      var m = Math.floor((a + 11 * h + 22 * l) / 451);
      var month = Math.floor((h + l - 7 * m + 114) / 31);
      var day = (h + l - 7 * m + 114) % 31;
      day = Math.round(day + 1);
      cache[year] = new Date(year, month - 1, day);
    }
    return cache[year];
  }

  function isBussUndBettag(date) {
    if (date.getMonth() !== 10) return false;

    // The last Wednesday before Nov 23rd
    var year = date.getFullYear();
    var dayOfWeek = new Date(year, 10, 22).getDay();
    var daysAdjust = dayOfWeek - 3;
    if (daysAdjust < 0) daysAdjust += 7;
    var day = new Date(year, 11, 22 - daysAdjust);
    return day.getDate() === date.getDate();
  }

  exports.resetHolidays = function () {
    exports.holidays = {
      Neujahrstag: true,
      Karfreitag: true,
      Ostersonntag: true,
      Ostermontag: true,
      'Tag der Arbeit': true,
      'Christi Himmelfahrt': true,
      Pfingstmontag: true,
      Pfingstsonntag: true,
      'Tag der Deutschen Einheit': true,
      '1. Weihnachtstag': true,
      '2. Weihnachtstag': true
    };
  };

  exports.setState = function (state) {
    exports.resetHolidays();
    switch (state) {
    case 'bw':
      exports.holidays['Heilige Drei Könige'] = true;
      exports.holidays.Fronleichnam = true;
      exports.holidays.Allerheiligen = true;
      break;
    case 'by':
      exports.holidays['Heilige Drei Könige'] = true;
      exports.holidays.Fronleichnam = true;
      exports.holidays['Mariä Himmelfahrt'] = true;
      exports.holidays.Allerheiligen = true;
      break;
    case 'bb':
      exports.holidays.Reformationstag = true;
      break;
    case 'he':
      exports.holidays.Fronleichnam = true;
      break;
    case 'mv':
      exports.holidays.Reformationstag = true;
      break;
    case 'nw':
    case 'rp':
      exports.holidays.Fronleichnam = true;
      exports.holidays.Allerheiligen = true;
      break;
    case 'sl':
      exports.holidays.Fronleichnam = true;
      exports.holidays['Mariä Himmelfahrt'] = true;
      exports.holidays.Allerheiligen = true;
      break;
    case 'sn':
      exports.holidays.Reformationstag = true;
      exports.holidays['Buß- und Bettag'] = true;
      break;
    case 'st':
      exports.holidays['Heilige Drei Könige'] = true;
      exports.holidays.Reformationstag = true;
      break;
    case 'th':
      exports.holidays.Reformationstag = true;
      break;
    }
  };

  exports.isHoliday = function (date) {
    if (date && typeof date.toDate === 'function') date = date.toDate();
    var year = date.getFullYear();
    var month = date.getMonth();
    var day = date.getDate();

    function check(name, m, d, override) {
      return (override || exports.holidays[name]) && month === m && day === d ? name : false;
    }

    // check fixed holidays
    var r;
    if (r = check('Neujahrstag', 0, 1)) return r;
    if (r = check('Heilige Drei Könige', 0, 6)) return r;
    if (r = check('Tag der Arbeit', 4, 1)) return r;
    if (r = check('Augsburger Friedensfest', 7, 8)) return r;
    if (r = check('Mariä Himmelfahrt', 7, 15)) return r;
    if (r = check('Tag der Deutschen Einheit', 9, 3)) return r;
    if (r = check('Reformationstag', 9, 31, year === 2017)) return r;
    if (r = check('Allerheiligen', 10, 1)) return r;
    if (r = check('Heiligabend', 11, 24)) return r;
    if (r = check('1. Weihnachtstag', 11, 25)) return r;
    if (r = check('2. Weihnachtstag', 11, 26)) return r;
    if (r = check('Silvester', 11, 31)) return r;

    // check variable holidays
    var tsYearStart = new Date(year, 0, 1).valueOf();
    var easterDays = Math.round((calculateEasterSunday(year).valueOf() - tsYearStart) / 86400000);
    var diff = Math.round((new Date(year, month, day).valueOf() - tsYearStart) / 86400000) - easterDays;

    function checkVar(name, d) {
      return exports.holidays[name] && diff === d ? name : false;
    }

    if (r = checkVar('Rosenmontag', -48)) return r;
    if (r = checkVar('Gründonnerstag', -3)) return r;
    if (r = checkVar('Karfreitag', -2)) return r;
    if (r = checkVar('Ostersonntag', 0)) return r;
    if (r = checkVar('Ostermontag', 1)) return r;
    if (r = checkVar('Christi Himmelfahrt', 39)) return r;
    if (r = checkVar('Pfingstsonntag', 49)) return r;
    if (r = checkVar('Pfingstmontag', 50)) return r;
    if (r = checkVar('Fronleichnam', 60)) return r;

    // check Bu&- und Bettag
    if (exports.holidays['Buß- und Bettag'] && isBussUndBettag(date)) return 'Buß- und Bettag';

    return false;
  };

  exports.isWorkday = function (date) {
    if (date && typeof date.toDate === 'function') date = date.toDate();
    var day = date.getDay();
    if (day === 0 || day === 6) return false;
    return !exports.isHoliday(date);
  };
}(typeof exports === 'undefined' ? window.holiday = {} : exports));