easter-date/dist/easter-sunday.js

Calculate the date of Easter for a given year

/**
 * Returns the date of Easter for a given year.
 * Function is an alias for getEasterSunday() function
 * @param year
 */
export function getEaster(year) {
    const a = year % 19;
    const b = Math.floor(year / 100);
    const c = year % 100;
    const d = Math.floor(b / 4);
    const e = b % 4; // eslint-disable-line unicorn/prevent-abbreviations
    const f = Math.floor((b + 8) / 25);
    const g = Math.floor((b - f + 1) / 3);
    const h = (19 * a + b - d - g + 15) % 30;
    const i = Math.floor(c / 4);
    const k = c % 4;
    const l = (32 + 2 * e + 2 * i - h - k) % 7;
    const m = Math.floor((a + 11 * h + 22 * l) / 451);
    const month = Math.floor((h + l - 7 * m + 114) / 31);
    const day = ((h + l - 7 * m + 114) % 31) + 1;
    return new Date(Date.UTC(year, month - 1, day));
}
/**
 * Returns true if the given date is Easter Sunday.
 * @param date
 */
export function isEaster(date) {
    const easter = getEaster(date.getFullYear());
    return (date.getFullYear() === easter.getFullYear() &&
        date.getMonth() === easter.getMonth() &&
        date.getDate() === easter.getDate());
}
/**
 * Returns the date of Easter for a given year.
 * @param year
 */
export function getEasterSunday(year) {
    return getEaster(year);
}
/**
 * Returns true if the given date is Easter Sunday.
 * @param date
 */
export function isEasterSunday(date) {
    return isEaster(date);
}