347 lines
8.7 KiB
JavaScript
347 lines
8.7 KiB
JavaScript
'use strict';
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Object.defineProperty(exports, '__esModule', { value: true });
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/**
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* Earth's hemispheres.
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*
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* @typedef {string} Hemisphere
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* @enum {Hemisphere}
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*/
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const Hemisphere = {
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NORTHERN: "Northern",
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SOUTHERN: "Southern",
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};
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/**
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* Enumeration of lunar phases as emoji
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*
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* @typedef {string} LunarEmoji
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*/
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const LunarEmoji = {
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/**
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* Enumeration of lunar phases as emoji for the Northern Hemisphere.
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* @num {LunarPhase}
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*/
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NorthernHemisphere: {
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NEW: "🌑",
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WAXING_CRESCENT: "🌒",
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FIRST_QUARTER: "🌓",
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WAXING_GIBBOUS: "🌔",
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FULL: "🌕",
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WANING_GIBBOUS: "🌖",
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LAST_QUARTER: "🌗",
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WANING_CRESCENT: "🌘",
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},
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/**
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* Enumeration of lunar phases as emoji for the Southern Hemisphere.
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* @num {LunarPhase}
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*/
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SouthernHemisphere: {
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NEW: "🌑",
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WAXING_CRESCENT: "🌘",
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FIRST_QUARTER: "🌗",
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WAXING_GIBBOUS: "🌖",
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FULL: "🌕",
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WANING_GIBBOUS: "🌔",
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LAST_QUARTER: "🌓",
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WANING_CRESCENT: "🌒",
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},
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};
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/**
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* Lunar month, time between two successive syzygies of the
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* same type: new moons or full moons
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*
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* @typedef {string} LunarMonth
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* @enum {LunarMonth}
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*/
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const LunarMonth = {
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ANOMALISTIC: "Anomalistic",
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DRACONIC: "Draconic",
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SIDEREAL: "Sidereal",
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SYNODIC: "Synodic",
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TROPICAL: "Tropical",
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};
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/**
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* Enumeration of lunar phases
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*
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* @typedef {string} LunarPhase
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* @enum {LunarPhase}
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*/
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const LunarPhase = {
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NEW: "New",
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WAXING_CRESCENT: "Waxing Crescent",
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FIRST_QUARTER: "First Quarter",
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WAXING_GIBBOUS: "Waxing Gibbous",
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FULL: "Full",
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WANING_GIBBOUS: "Waning Gibbous",
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LAST_QUARTER: "Last Quarter",
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WANING_CRESCENT: "Waning Crescent",
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};
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/**
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* Units of measure
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*
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* @typedef {string} Unit
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* @enum {Unit}
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*/
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const Unit = {
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EARTH_RADII: "Earth Radii",
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KILOMETERS: "km",
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MILES: "m",
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};
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/**
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* Timestamp epoch, January 1, 1970, in Julian Days.
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* @type {number}
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*/
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const EPOCH = 2440587.5;
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/**
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* Lunation 1 as the first new moon of 1923 at approximately
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* 02:41 UTC, January 17, 1923 per Ernest William Brown's lunar theory.
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* @type {number}
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*/
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const LUNATION_BASE_JULIAN_DAY = 2423436.6115277777;
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/**
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* Length of one phase (1/8 of a synodic month) in Earth days.
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* @type {number}
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*/
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const PHASE_LENGTH = 3.69132346322;
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/**
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* Orbital period of the Moon from perigee to apogee and back to perigee
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* @type {number}
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*/
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const ANOMALISTIC_MONTH = 27.55454988;
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/**
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* Length of one synodic month - lunation, or days for the phases to complete a cycle.
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* Time between two identical syzygies, equivalent of 29.53059 Earth days.
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*
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* Based on Mean Synodic Month, 2000 AD mean solar days.
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* @type {number}
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*/
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const SYNODIC_MONTH = 29.53058770576;
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var Time = /*#__PURE__*/Object.freeze({
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__proto__: null,
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EPOCH: EPOCH,
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LUNATION_BASE_JULIAN_DAY: LUNATION_BASE_JULIAN_DAY,
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PHASE_LENGTH: PHASE_LENGTH,
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ANOMALISTIC_MONTH: ANOMALISTIC_MONTH,
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SYNODIC_MONTH: SYNODIC_MONTH
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});
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/**
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* Normalization utility for percentage calculations.
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*
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* @param {number} value Percent value.
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* @returns {number} Normalized value
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*/
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const normalize = (value) => {
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value -= Math.floor(value);
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if (value < 0) {
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value += 1;
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}
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return value;
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};
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/**
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* Julian day from Gregorian date.
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* @param {Date} date Gregorian date to convert to Julian day.
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* @returns {number} Julian Day
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*/
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const fromDate = (date = new Date()) => {
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const time = date.getTime();
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return time / 86400000 - date.getTimezoneOffset() / 1440 + EPOCH;
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};
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/**
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* Gregorian date from Julian day
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* @param {number} julian Julian dat to convert to Gregorian date
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* @returns {Date} Gregorian date
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*/
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const toDate = (julian) => {
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let date = new Date();
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date.setTime((julian - EPOCH + date.getTimezoneOffset() / 1440) * 86400000);
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return date;
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};
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var JulianDay = /*#__PURE__*/Object.freeze({
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__proto__: null,
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fromDate: fromDate,
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toDate: toDate
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});
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/**
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* Moon's age, or Earth days since the last new moon.
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*
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* @param {Date} date Date used for calculation.
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* @returns {number} Age of the moon, normalized within a 29.53059 Earth days calendar.
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*/
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const lunarAge = (date = new Date()) => {
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const percent = lunarAgePercent(date);
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return percent * SYNODIC_MONTH;
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};
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/**
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* Percentage through the lunar synodic month.
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*
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* @param {Date} date Date used for calculation.
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* @returns {number} Percentage through the lunar month.
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*/
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const lunarAgePercent = (date = new Date()) => {
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return normalize((fromDate(date) - 2451550.1) / SYNODIC_MONTH);
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};
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/**
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* Brown Lunation Number (BLN), per Ernest William Brown's lunar theory,
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* defining Lunation 1 as the first new moon of 1923 at
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* approximately 02:41 UTC, January 17, 1923.
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*
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* @param {Date} date Date used for calculation.
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* @returns {number} Lunation Number
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*/
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const lunationNumber = (date = new Date()) => {
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return Math.round((fromDate(date) - LUNATION_BASE_JULIAN_DAY) / SYNODIC_MONTH) + 1;
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};
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/**
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* Distance to the moon measured in units of Earth radii, with
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* perigee at 56 and apogee at 63.8.
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*
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* @param {Date} date Date used for calculation
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* @returns {number} Distance to the moon in Earth radii
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*/
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const lunarDistance = (date = new Date()) => {
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const julian = fromDate(date);
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const agePercent = lunarAgePercent(date);
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const radians = agePercent * 2 * Math.PI;
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const percent = 2 * Math.PI * normalize((julian - 2451562.2) / ANOMALISTIC_MONTH);
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return 60.4 - 3.3 * Math.cos(percent) - 0.6 * Math.cos(2 * radians - percent) - 0.5 * Math.cos(2 * radians);
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};
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/**
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* Name of the lunar phase per date submitted.
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*
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* @param {Date} date Date used to calculate lunar phase.
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* @returns {string} Name as string of the current lunar phase.
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*/
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const lunarPhase = (date = new Date()) => {
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const age = lunarAge(date);
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if (age < 1.84566173161) return LunarPhase.NEW;
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else if (age < 5.53698519483) return LunarPhase.WAXING_CRESCENT;
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else if (age < 9.22830865805) return LunarPhase.FIRST_QUARTER;
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else if (age < 12.91963212127) return LunarPhase.WAXING_GIBBOUS;
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else if (age < 16.61095558449) return LunarPhase.FULL;
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else if (age < 20.30227904771) return LunarPhase.WANING_GIBBOUS;
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else if (age < 23.99360251093) return LunarPhase.LAST_QUARTER;
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else if (age < 27.68492597415) return LunarPhase.WANING_CRESCENT;
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return LunarPhase.NEW;
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};
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/**
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* Emoji of the lunar phase per date submitted.
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*
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* @param {Date} date Date used to calculate lunar phase.
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* @param {Hemisphere} hemisphere Northern or Southern Hemisphere.
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* @returns Emoji of the current lunar phase.
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*/
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const lunarPhaseEmoji = (date = new Date(), hemisphere = Hemisphere.NORTHERN) => {
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const phase = lunarPhase(date);
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return emojiForLunarPhase(phase, hemisphere);
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};
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/**
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* Emoji for specified lunar phase.
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*
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* @param {LunarPhase} phase Lunar phase, per the LunarPhase enum
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* @param {Hemisphere} hemisphere Northern or Southern Hemisphere.
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* @returns {string} Emoji of the current lunar phase.
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*/
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const emojiForLunarPhase = (phase, hemisphere = Hemisphere.NORTHERN) => {
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let emoji;
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if (hemisphere === Hemisphere.SOUTHERN) {
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emoji = LunarEmoji.SouthernHemisphere;
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} else {
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emoji = LunarEmoji.NorthernHemisphere;
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}
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switch (phase) {
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case LunarPhase.WANING_CRESCENT:
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return emoji["WANING_CRESCENT"];
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case LunarPhase.LAST_QUARTER:
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return emoji["LAST_QUARTER"];
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case LunarPhase.WANING_GIBBOUS:
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return emoji["WANING_GIBBOUS"];
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case LunarPhase.FULL:
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return emoji["FULL"];
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case LunarPhase.WAXING_GIBBOUS:
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return emoji["WAXING_GIBBOUS"];
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case LunarPhase.FIRST_QUARTER:
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return emoji["FIRST_QUARTER"];
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case LunarPhase.WAXING_CRESCENT:
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return emoji["WAXING_CRESCENT"];
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default:
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case LunarPhase.NEW:
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return emoji["NEW"];
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}
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};
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/**
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* Whether the moon is currently waxing (growing).
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*
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* @param {Date} date Date used for calculation.
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* @returns {boolean} True if moon is waxing.
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*/
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const isWaxing = (date = new Date()) => {
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const age = lunarAge(date);
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return age <= 14.765;
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};
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/**
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* Whether the moon is currently waning (shrinking).
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*
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* @param {Date} date Date used for calculation.
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* @returns {boolean} True if moon is waning.
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*/
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const isWaning = (date = new Date()) => {
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const age = lunarAge(date);
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return age > 14.765;
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};
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var Moon = /*#__PURE__*/Object.freeze({
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__proto__: null,
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lunarAge: lunarAge,
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lunarAgePercent: lunarAgePercent,
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lunationNumber: lunationNumber,
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lunarDistance: lunarDistance,
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lunarPhase: lunarPhase,
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lunarPhaseEmoji: lunarPhaseEmoji,
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emojiForLunarPhase: emojiForLunarPhase,
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isWaxing: isWaxing,
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isWaning: isWaning
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});
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exports.Hemisphere = Hemisphere;
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exports.JulianDay = JulianDay;
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exports.LunarEmoji = LunarEmoji;
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exports.LunarMonth = LunarMonth;
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exports.LunarPhase = LunarPhase;
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exports.Moon = Moon;
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exports.Time = Time;
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exports.Unit = Unit;
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//# sourceMappingURL=lunarphase-js.js.map
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