Get moon phase by Date, written in TypeScript. Accurate from year 1900 to 2199 inclusive.

getMoonPhase.ts

export { EMoonPhase, EMoonPhaseName, MOON_PHASE_NAMES, moonPhase }


const { round, trunc: truncate } = Math


enum EMoonPhase {
  New = 0,
  WaxingCrescent,
  QuarterMoon,
  WaxingGibbous,
  Full,
  WaningGibbous,
  LastQuarter,
  WaningCrescent,
  COUNT = 8
}


enum EMoonPhaseName {
  New = 'New',
  WaxingCrescent = 'Waxing Crescent',
  QuarterMoon = 'Quarter Moon',
  WaxingGibbous = 'Waxing Gibbous',
  Full = 'Full',
  WaningGibbous = 'Waning Gibbous',
  LastQuarter = 'Last Quarter',
  WaningCrescent = 'Waning Crescent',
  COUNT = 'COUNT'
}


const MOON_PHASE_NAMES: EMoonPhaseName[] = [ // Look-up table.
  EMoonPhaseName.New,
  EMoonPhaseName.WaxingCrescent,
  EMoonPhaseName.QuarterMoon,
  EMoonPhaseName.WaxingGibbous,
  EMoonPhaseName.Full,
  EMoonPhaseName.WaningGibbous,
  EMoonPhaseName.LastQuarter,
  EMoonPhaseName.WaningCrescent,
  EMoonPhaseName.COUNT
]


// Reference: http://individual.utoronto.ca/kalendis/lunar/#FALC
// Also known as a synodic month.
// An average synodic month takes 29 days, 12 hours, 44 minutes, 3 seconds.
const LUNAR_CYCLE = 29.53058770576

const DAYS_PER_YEAR = 365.25
const DAYS_PER_MONTH = 30.6

// Number of days since known new moon on `1900-01-01`.
const DAYS_SINCE_NEW_MOON_1900_01_01 = 694039.09


interface IResult { name: EMoonPhaseName, phase: EMoonPhase }


// Ported from `http://www.voidware.com/moon_phase.htm`.
function moonPhase (date: Date = new Date()): IResult {

  // let year = date.getYear()
  let year: number = date.getFullYear()

  let month: number = date.getMonth()
  const day: number = date.getDay()

  if (month < 3) {
    year--
    month += 12
  }

  month++

  let totalDaysElapsed: number = DAYS_PER_YEAR
    * year
    + DAYS_PER_MONTH
    * month
    + day
    - DAYS_SINCE_NEW_MOON_1900_01_01

  totalDaysElapsed /= LUNAR_CYCLE // Divide by the lunar cycle.

  let phase: number = truncate(totalDaysElapsed)

  /*
    Subtract integer part to leave fractional part of original
    `totalDaysElapsed`.
   */
  totalDaysElapsed -= phase

  // Scale fraction from `0-8`.
  phase = round(totalDaysElapsed * 8)
  phase = phase & 7 // `0` and `8` are the same so turn `8` into `0`.

  if (phase >= EMoonPhase.COUNT || phase < EMoonPhase.New)
    throw new Error(`Invalid moon phase: ${phase}`)

  return { phase, name: MOON_PHASE_NAMES[phase] }

}

What is the license of this nice code? MIT?

@Alkalurops The essence of the algorithm was taken from http://www.voidware.com/moon_phase.htm/https://gist.github.com/endel/dfe6bb2fbe679781948c which does not name a source nor license unfortunately. I only ported it to TypeScript and modified it to suit my coding style and preferences.

Datatypevoid

Great work!can make this as react native app

@Alkalurops The essence of the algorithm was taken from http://www.voidware.com/moon_phase.htm/https://gist.github.com/endel/dfe6bb2fbe679781948c which does not name a source nor license unfortunately. I only ported it to TypeScript and modified it to suit my coding style and preferences.

Alright thanks!

Not sure about typescript, but if same as JS it looks to be some errors:

• Date.prototype.getDay() returns day of week, not day of month, use .getDate()
• Date.prototype.getMonth() is zero based, use .getMonth() + 1
• DAYS_SINCE_NEW_MOON_1900_01_01 - not sure what that is ( 694039.09).

It is close to days from year 0 to March 1900 - more precisely Tuesday March 20th 1900, or Thursday 21st if one count form year 1. Wednesday 20th of March 1901 had a new moon at 12:52 UTC+0, but that is not 1st of January ... 1st of January 1900 had a new-moon at 13:51 (if I remember correctly), 693595 or 693597 days from 001-01-01 or 693961 MySQL TO_DAYS from 0000-00-00.

Does it have something to do with Julian/Gregorian/Roman calendars?

Here is a revised version, which works (also, added icons and an override)

export {
  EMoonPhase,
  moonIcons,
  moonPhaseAlt,
  EMoonPhaseName,
  MOON_PHASE_NAMES,
  moonPhase,
}

const { round, trunc: truncate } = Math

enum EMoonPhase {
  New = 0,
  WaxingCrescent,
  QuarterMoon,
  WaxingGibbous,
  Full,
  WaningGibbous,
  LastQuarter,
  WaningCrescent,
  COUNT = 8,
}

const moonIcons: [
  New: string,
  WaxingCrescent: string,
  QuarterMoon: string,
  WaxingGibbous: string,
  Full: string,
  WaningGibbous: string,
  LastQuarter: string,
  WaningCrescent: string
] = ["🌑", "🌒", "🌓", "🌔", "🌕", "🌖", "🌗", "🌘"]

enum EMoonPhaseName {
  New = "New",
  WaxingCrescent = "Waxing Crescent",
  QuarterMoon = "Quarter Moon",
  WaxingGibbous = "Waxing Gibbous",
  Full = "Full",
  WaningGibbous = "Waning Gibbous",
  LastQuarter = "Last Quarter",
  WaningCrescent = "Waning Crescent",
  COUNT = "COUNT",
}

const MOON_PHASE_NAMES: EMoonPhaseName[] = [
  // Look-up table.
  EMoonPhaseName.New,
  EMoonPhaseName.WaxingCrescent,
  EMoonPhaseName.QuarterMoon,
  EMoonPhaseName.WaxingGibbous,
  EMoonPhaseName.Full,
  EMoonPhaseName.WaningGibbous,
  EMoonPhaseName.LastQuarter,
  EMoonPhaseName.WaningCrescent,
  EMoonPhaseName.COUNT,
]

// Reference: http://individual.utoronto.ca/kalendis/lunar/#FALC
// Also known as a synodic month.
// An average synodic month takes 29 days, 12 hours, 44 minutes, 3 seconds.
const LUNAR_CYCLE = 29.5305882 // 29.53058770576

const DAYS_PER_YEAR = 365.25
const DAYS_PER_MONTH = 30.6

// Number of days since known new moon on `1900-01-01`.
const DAYS_SINCE_NEW_MOON_1900_01_01 = 694039.09

interface IResult {
  name: EMoonPhaseName
  phase: EMoonPhase
  icon: string
}

function moonPhaseAlt(date: Date = new Date()): IResult {
  // let year = date.getYear()
  let year: number = date.getFullYear()

  let month: number = date.getMonth() + 1
  const day: number = date.getDate()
  return moonPhase(year, month, day)
}

// Ported from `http://www.voidware.com/moon_phase.htm`.
function moonPhase(year: number, month: number, day: number): IResult {
  if (month < 3) {
    year--
    month += 12
  }

  month += 1

  let totalDaysElapsed: number =
    DAYS_PER_YEAR * year +
    DAYS_PER_MONTH * month +
    day -
    DAYS_SINCE_NEW_MOON_1900_01_01

  totalDaysElapsed /= LUNAR_CYCLE // Divide by the lunar cycle.

  let phase: number = truncate(totalDaysElapsed)

  /*
    Subtract integer part to leave fractional part of original
    `totalDaysElapsed`.
   */
  totalDaysElapsed -= phase

  // Scale fraction from `0-8`.
  phase = round(totalDaysElapsed * 8)
  if (phase >= 8) phase = 0 // `0` and `8` are the same so turn `8` into `0`.

  if (phase >= EMoonPhase.COUNT || phase < EMoonPhase.New)
    throw new Error(`Invalid moon phase: ${phase}`)

  return { phase, name: MOON_PHASE_NAMES[phase], icon: moonIcons[phase] }
}

Here is a revised version, which works (also, added icons and an override)

export {
  EMoonPhase,
  moonIcons,
  moonPhaseAlt,
  EMoonPhaseName,
  MOON_PHASE_NAMES,
  moonPhase,
}

const { round, trunc: truncate } = Math

enum EMoonPhase {
  New = 0,
  WaxingCrescent,
  QuarterMoon,
  WaxingGibbous,
  Full,
  WaningGibbous,
  LastQuarter,
  WaningCrescent,
  COUNT = 8,
}

const moonIcons: [
  New: string,
  WaxingCrescent: string,
  QuarterMoon: string,
  WaxingGibbous: string,
  Full: string,
  WaningGibbous: string,
  LastQuarter: string,
  WaningCrescent: string
] = ["🌑", "🌒", "🌓", "🌔", "🌕", "🌖", "🌗", "🌘"]

enum EMoonPhaseName {
  New = "New",
  WaxingCrescent = "Waxing Crescent",
  QuarterMoon = "Quarter Moon",
  WaxingGibbous = "Waxing Gibbous",
  Full = "Full",
  WaningGibbous = "Waning Gibbous",
  LastQuarter = "Last Quarter",
  WaningCrescent = "Waning Crescent",
  COUNT = "COUNT",
}

const MOON_PHASE_NAMES: EMoonPhaseName[] = [
  // Look-up table.
  EMoonPhaseName.New,
  EMoonPhaseName.WaxingCrescent,
  EMoonPhaseName.QuarterMoon,
  EMoonPhaseName.WaxingGibbous,
  EMoonPhaseName.Full,
  EMoonPhaseName.WaningGibbous,
  EMoonPhaseName.LastQuarter,
  EMoonPhaseName.WaningCrescent,
  EMoonPhaseName.COUNT,
]

// Reference: http://individual.utoronto.ca/kalendis/lunar/#FALC
// Also known as a synodic month.
// An average synodic month takes 29 days, 12 hours, 44 minutes, 3 seconds.
const LUNAR_CYCLE = 29.5305882 // 29.53058770576

const DAYS_PER_YEAR = 365.25
const DAYS_PER_MONTH = 30.6

// Number of days since known new moon on `1900-01-01`.
const DAYS_SINCE_NEW_MOON_1900_01_01 = 694039.09

interface IResult {
  name: EMoonPhaseName
  phase: EMoonPhase
  icon: string
}

function moonPhaseAlt(date: Date = new Date()): IResult {
  // let year = date.getYear()
  let year: number = date.getFullYear()

  let month: number = date.getMonth() + 1
  const day: number = date.getDate()
  return moonPhase(year, month, day)
}

// Ported from `http://www.voidware.com/moon_phase.htm`.
function moonPhase(year: number, month: number, day: number): IResult {
  if (month < 3) {
    year--
    month += 12
  }

  month += 1

  let totalDaysElapsed: number =
    DAYS_PER_YEAR * year +
    DAYS_PER_MONTH * month +
    day -
    DAYS_SINCE_NEW_MOON_1900_01_01

  totalDaysElapsed /= LUNAR_CYCLE // Divide by the lunar cycle.

  let phase: number = truncate(totalDaysElapsed)

  /*
    Subtract integer part to leave fractional part of original
    `totalDaysElapsed`.
   */
  totalDaysElapsed -= phase

  // Scale fraction from `0-8`.
  phase = round(totalDaysElapsed * 8)
  if (phase >= 8) phase = 0 // `0` and `8` are the same so turn `8` into `0`.

  if (phase >= EMoonPhase.COUNT || phase < EMoonPhase.New)
    throw new Error(`Invalid moon phase: ${phase}`)

  return { phase, name: MOON_PHASE_NAMES[phase], icon: moonIcons[phase] }
}

🔥 🚀 👍 Love the icon addition.

This is awesome, thank you. I cleaned up some of the typescript, improved some variable names, and added the lunary day:

export const MOON_ICONS = ["🌑", "🌒", "🌓", "🌔", "🌕", "🌖", "🌗", "🌘"] as const;

export const MOON_PHASE_NAMES = [
  "New",
  "Waxing Crescent",
  "Quarter Moon",
  "Waxing Gibbous",
  "Full",
  "Waning Gibbous",
  "Last Quarter",
  "Waning Crescent",
] as const;

/**
 * Reference: http://individual.utoronto.ca/kalendis/lunar/#FALC - Also known as a synodic month.
 * An average synodic month takes 29 days, 12 hours, 44 minutes, 3 seconds.
 */
export const LUNAR_CYCLE = 29.5305882; // 29.53058770576

export const DAYS_PER_YEAR = 365.25;

export const DAYS_PER_MONTH = 30.6;

/** The number of days between `0 AD` and the new moon on `1900-01-01`. */
export const NEW_MOON_REFERENCE = 694039.09;

// Ported from `http://www.voidware.com/moon_phase.htm`.
export const getMoonPhase = (date: Date = new Date()) => {
  let year = date.getFullYear();
  let month = date.getMonth() + 1;
  const day = date.getDate();

  if (month < 3) {
    year -= 1;
    month += 12;
  }

  month += 1;

  const daysSinceZeroAd = DAYS_PER_YEAR * year + DAYS_PER_MONTH * month + day;
  const daysSinceNewMoonReference = daysSinceZeroAd - NEW_MOON_REFERENCE;

  const numberOfCyclesSinceReference = daysSinceNewMoonReference / LUNAR_CYCLE;

  const percentageOfCycleComplete = numberOfCyclesSinceReference - Math.trunc(numberOfCyclesSinceReference);

  // Scale fraction from 0 to 8
  let phase = Math.round(percentageOfCycleComplete * 8);
  if (phase >= 8) phase = 0; // `0` and `8` are the same so turn `8` into `0`.

  // Scale fraction from 0 to `LUNAR_CYCLE`
  const lunarDay = Math.round(percentageOfCycleComplete * LUNAR_CYCLE);

  if (!MOON_PHASE_NAMES[phase]) throw new Error(`Invalid moon phase: ${phase}`);

  return { lunarDay, name: MOON_PHASE_NAMES[phase], icon: MOON_ICONS[phase] };
};

This is awesome, thank you. I cleaned up some of the typescript, improved some variable names, and added the lunary day:

export const MOON_ICONS: [
  New: string,
  WaxingCrescent: string,
  QuarterMoon: string,
  WaxingGibbous: string,
  Full: string,
  WaningGibbous: string,
  LastQuarter: string,
  WaningCrescent: string
] = ["🌑", "🌒", "🌓", "🌔", "🌕", "🌖", "🌗", "🌘"];

export const MOON_PHASE_NAMES = [
  "New",
  "Waxing Crescent",
  "Quarter Moon",
  "Waxing Gibbous",
  "Full",
  "Waning Gibbous",
  "Last Quarter",
  "Waning Crescent",
] as const;

/**
 * Reference: http://individual.utoronto.ca/kalendis/lunar/#FALC - Also known as a synodic month.
 * An average synodic month takes 29 days, 12 hours, 44 minutes, 3 seconds.
 */
export const LUNAR_CYCLE = 29.5305882; // 29.53058770576

export const DAYS_PER_YEAR = 365.25;

export const DAYS_PER_MONTH = 30.6;

/** The number of days between `0 AD` and the new moon on `1900-01-01`. */
export const NEW_MOON_REFERENCE = 694039.09;

// Ported from `http://www.voidware.com/moon_phase.htm`.
export const getMoonPhase = (date: Date = new Date()) => {
  let year = date.getFullYear();
  let month = date.getMonth() + 1;
  const day = date.getDate();

  if (month < 3) {
    year -= 1;
    month += 12;
  }

  month += 1;

  const daysSinceZeroAd = DAYS_PER_YEAR * year + DAYS_PER_MONTH * month + day;
  const daysSinceNewMoonReference = daysSinceZeroAd - NEW_MOON_REFERENCE;

  const numberOfCyclesSinceReference = daysSinceNewMoonReference / LUNAR_CYCLE;

  const percentageOfCycleComplete = numberOfCyclesSinceReference - Math.trunc(numberOfCyclesSinceReference);

  // Scale fraction from 0 to 8
  let phase = Math.round(percentageOfCycleComplete * 8);
  if (phase >= 8) phase = 0; // `0` and `8` are the same so turn `8` into `0`.

  // Scale fraction from 0 to `LUNAR_CYCLE`
  const lunarDay = Math.round(percentageOfCycleComplete * LUNAR_CYCLE);

  if (!MOON_PHASE_NAMES[phase]) throw new Error(`Invalid moon phase: ${phase}`);

  return { lunarDay, name: MOON_PHASE_NAMES[phase], icon: MOON_ICONS[phase] };
};

hey Eric can you send your emil or WhatsApp

GitHub doesn't allow users to share emails. What's up?

GitHub doesn't allow users to share emails. What's up?

i think her can not connect. i tried to inter to your website but dont work?

can you develop , calculate moon manzel?

Yes, I think that wouldn't be too hard to add with some investigation into calculating lunar degrees.

how can have contact with you?

sent you a repo collab

Yes, I think that wouldn't be too hard to add with some investigation into calculating lunar degrees.

how contact with you

You're cluttering up the gist man. I sent you a repo collaboration invite so you can contact me through the codebase.

You're cluttering up the gist man. I sent you a repo collaboration invite so you can contact me through the codebase.

i didnt have and received any thing

i accept it.now what?

This is my last message here. Check the README. My email is there.