date-object/calendars/umd/gregorian.js

JavaScript library for working with Date and Time in different calendars and locals

(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
	typeof define === 'function' && define.amd ? define(factory) :
	(global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.gregorian = factory());
})(this, (function () { 'use strict';

	function getDefaultExportFromCjs (x) {
		return x && x.__esModule && Object.prototype.hasOwnProperty.call(x, 'default') ? x['default'] : x;
	}

	const gregorian = {
	  name: "gregorian",
	  startYear: 1,
	  yearLength: 365,
	  epoch: 1721424,
	  century: 20,
	  weekStartDayIndex: 1,
	  getMonthLengths(isLeap) {
	    return [31, isLeap ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
	  },
	  isLeap(year) {
	    return (year % 4 === 0 && year % 100 !== 0) || year % 400 === 0;
	  },
	  getLeaps(currentYear) {
	    if (currentYear === 0) return;

	    let year = currentYear > 0 ? 1 : -1;

	    let leaps = [],
	      condition = () =>
	        currentYear > 0 ? year <= currentYear : currentYear <= year,
	      increase = () => (currentYear > 0 ? year++ : year--);

	    while (condition()) {
	      if (this.isLeap(year)) leaps.push(year);

	      increase();
	    }

	    return leaps;
	  },
	  getDayOfYear({ year, month, day }) {
	    let monthLengths = this.getMonthLengths(this.isLeap(year));

	    for (let i = 0; i < month.index; i++) {
	      day += monthLengths[i];
	    }

	    return day;
	  },
	  getAllDays(date) {
	    const { year } = date;

	    return (
	      this.yearLength * (year - 1) +
	      this.leapsLength(year) +
	      this.getDayOfYear(date)
	    );
	  },
	  leapsLength(year) {
	    return (
	      (((year - 1) / 4) | 0) +
	      (-((year - 1) / 100) | 0) +
	      (((year - 1) / 400) | 0)
	    );
	  },
	  guessYear(days, currentYear) {
	    let year = ~~(days / 365.24);

	    return year + (currentYear > 0 ? 1 : -1);
	  },
	};

	var gregorian_1 = gregorian;

	var gregorian$1 = /*@__PURE__*/getDefaultExportFromCjs(gregorian_1);

	return gregorian$1;

}));