Created
March 18, 2024 15:29
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| /** | |
| * Calculates the date of Easter Sunday for a given year in the Gregorian calendar. | |
| * | |
| * The method used is the Anonymous Gregorian algorithm (also known as Computus), | |
| * which calculates Easter as the first Sunday after the first ecclesiastical full moon | |
| * that occurs on or after March 21. | |
| * | |
| * @param year The year for which to calculate Easter Sunday (e.g., 2024). | |
| * @returns A Date object representing Easter Sunday for the given year. | |
| */ | |
| function calculateEaster(year: number): Date { | |
| // The Golden Number - 1 | |
| const G = year % 19; | |
| // Century number | |
| const C = Math.floor(year / 100); | |
| // Corrections for leap years and moon's orbit | |
| const H = (C - Math.floor(C / 4) - Math.floor((8 * C + 13) / 25) + 19 * G + 15) % 30; | |
| // Correction for Sunday | |
| const I = H - Math.floor(H / 28) * (1 - Math.floor(H / 28) * Math.floor(29 / (H + 1)) * Math.floor((21 - G) / 11)); | |
| // Weekday for the full moon | |
| const J = (year + Math.floor(year / 4) + I + 2 - C + Math.floor(C / 4)) % 7; | |
| // Number of days from March 21 to the Paschal full moon | |
| const L = I - J; | |
| // Month of Easter | |
| const month = 3 + Math.floor((L + 40) / 44); | |
| // Day of Easter | |
| const day = L + 28 - 31 * Math.floor(month / 4); | |
| // Return the date of Easter | |
| return new Date(year, month - 1, day); | |
| } | |
| // Example usage: | |
| const easterDate = calculateEaster(2024); | |
| console.log(`Easter 2024 falls on: ${easterDate.toDateString()}`); |
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