lunar converter

LunarSolarConverter.js

/**
 * Modified by isobar on 04/01/19.
 *
 * Created by isee15 on 15/1/14.
 */
/*
Usage:
    var converter = new LunarSolarConverter();
    var solar = new Solar();
    solar.solarYear = 1985;
    solar.solarMonth = 1;
    solar.solarDay = 15;
    var lunar = converter.SolarToLunar(solar);
    // 'lunarDay' => "25" 'lunarMonth' => "11" 'lunarYear' => "1984" 'chineseAnimal' => "鼠" 'chineseCycle' => "甲子" 
    console.log(lunar);
*/
function Lunar() {
    this.isleap = false;
    this.lunarDay = 0;
    this.lunarMonth = 0;
    this.lunarYear = 0;
    this.chineseAnimal = "";
    this.chineseCycle = "";
}

function Solar() {
    this.solarDay = 0;
    this.solarMonth = 0;
    this.solarYear = 0;
}

function LunarSolarConverter() {
    this.cycle10 = ["甲","乙","丙","丁","戊","己","庚","辛","壬","癸"];
    this.cycle12 = ["子","丑","寅","卯","辰","巳","午","未","申","酉","戌","亥"];
    
    this.chinese_animal = ["鼠","牛","虎","兔","龍","蛇","馬","羊","猴","雞","狗","豬"];
    
    this.lunar_month_days = [1887, 0x1694, 0x16aa, 0x4ad5,
        0xab6, 0xc4b7, 0x4ae, 0xa56, 0xb52a, 0x1d2a, 0xd54, 0x75aa, 0x156a,
        0x1096d, 0x95c, 0x14ae, 0xaa4d, 0x1a4c, 0x1b2a, 0x8d55, 0xad4,
        0x135a, 0x495d, 0x95c, 0xd49b, 0x149a, 0x1a4a, 0xbaa5, 0x16a8,
        0x1ad4, 0x52da, 0x12b6, 0xe937, 0x92e, 0x1496, 0xb64b, 0xd4a,
        0xda8, 0x95b5, 0x56c, 0x12ae, 0x492f, 0x92e, 0xcc96, 0x1a94,
        0x1d4a, 0xada9, 0xb5a, 0x56c, 0x726e, 0x125c, 0xf92d, 0x192a,
        0x1a94, 0xdb4a, 0x16aa, 0xad4, 0x955b, 0x4ba, 0x125a, 0x592b,
        0x152a, 0xf695, 0xd94, 0x16aa, 0xaab5, 0x9b4, 0x14b6, 0x6a57,
        0xa56, 0x1152a, 0x1d2a, 0xd54, 0xd5aa, 0x156a, 0x96c, 0x94ae,
        0x14ae, 0xa4c, 0x7d26, 0x1b2a, 0xeb55, 0xad4, 0x12da, 0xa95d,
        0x95a, 0x149a, 0x9a4d, 0x1a4a, 0x11aa5, 0x16a8, 0x16d4, 0xd2da,
        0x12b6, 0x936, 0x9497, 0x1496, 0x1564b, 0xd4a, 0xda8, 0xd5b4,
        0x156c, 0x12ae, 0xa92f, 0x92e, 0xc96, 0x6d4a, 0x1d4a, 0x10d65,
        0xb58, 0x156c, 0xb26d, 0x125c, 0x192c, 0x9a95, 0x1a94, 0x1b4a,
        0x4b55, 0xad4, 0xf55b, 0x4ba, 0x125a, 0xb92b, 0x152a, 0x1694,
        0x96aa, 0x15aa, 0x12ab5, 0x974, 0x14b6, 0xca57, 0xa56, 0x1526,
        0x8e95, 0xd54, 0x15aa, 0x49b5, 0x96c, 0xd4ae, 0x149c, 0x1a4c,
        0xbd26, 0x1aa6, 0xb54, 0x6d6a, 0x12da, 0x1695d, 0x95a, 0x149a,
        0xda4b, 0x1a4a, 0x1aa4, 0xbb54, 0x16b4, 0xada, 0x495b, 0x936,
        0xf497, 0x1496, 0x154a, 0xb6a5, 0xda4, 0x15b4, 0x6ab6, 0x126e,
        0x1092f, 0x92e, 0xc96, 0xcd4a, 0x1d4a, 0xd64, 0x956c, 0x155c,
        0x125c, 0x792e, 0x192c, 0xfa95, 0x1a94, 0x1b4a, 0xab55, 0xad4,
        0x14da, 0x8a5d, 0xa5a, 0x1152b, 0x152a, 0x1694, 0xd6aa, 0x15aa,
        0xab4, 0x94ba, 0x14b6, 0xa56, 0x7527, 0xd26, 0xee53, 0xd54, 0x15aa,
        0xa9b5, 0x96c, 0x14ae, 0x8a4e, 0x1a4c, 0x11d26, 0x1aa4, 0x1b54,
        0xcd6a, 0xada, 0x95c, 0x949d, 0x149a, 0x1a2a, 0x5b25, 0x1aa4,
        0xfb52, 0x16b4, 0xaba, 0xa95b, 0x936, 0x1496, 0x9a4b, 0x154a,
        0x136a5, 0xda4, 0x15ac];

    this.solar_1_1 = [1887, 0xec04c, 0xec23f, 0xec435, 0xec649,
        0xec83e, 0xeca51, 0xecc46, 0xece3a, 0xed04d, 0xed242, 0xed436,
        0xed64a, 0xed83f, 0xeda53, 0xedc48, 0xede3d, 0xee050, 0xee244,
        0xee439, 0xee64d, 0xee842, 0xeea36, 0xeec4a, 0xeee3e, 0xef052,
        0xef246, 0xef43a, 0xef64e, 0xef843, 0xefa37, 0xefc4b, 0xefe41,
        0xf0054, 0xf0248, 0xf043c, 0xf0650, 0xf0845, 0xf0a38, 0xf0c4d,
        0xf0e42, 0xf1037, 0xf124a, 0xf143e, 0xf1651, 0xf1846, 0xf1a3a,
        0xf1c4e, 0xf1e44, 0xf2038, 0xf224b, 0xf243f, 0xf2653, 0xf2848,
        0xf2a3b, 0xf2c4f, 0xf2e45, 0xf3039, 0xf324d, 0xf3442, 0xf3636,
        0xf384a, 0xf3a3d, 0xf3c51, 0xf3e46, 0xf403b, 0xf424e, 0xf4443,
        0xf4638, 0xf484c, 0xf4a3f, 0xf4c52, 0xf4e48, 0xf503c, 0xf524f,
        0xf5445, 0xf5639, 0xf584d, 0xf5a42, 0xf5c35, 0xf5e49, 0xf603e,
        0xf6251, 0xf6446, 0xf663b, 0xf684f, 0xf6a43, 0xf6c37, 0xf6e4b,
        0xf703f, 0xf7252, 0xf7447, 0xf763c, 0xf7850, 0xf7a45, 0xf7c39,
        0xf7e4d, 0xf8042, 0xf8254, 0xf8449, 0xf863d, 0xf8851, 0xf8a46,
        0xf8c3b, 0xf8e4f, 0xf9044, 0xf9237, 0xf944a, 0xf963f, 0xf9853,
        0xf9a47, 0xf9c3c, 0xf9e50, 0xfa045, 0xfa238, 0xfa44c, 0xfa641,
        0xfa836, 0xfaa49, 0xfac3d, 0xfae52, 0xfb047, 0xfb23a, 0xfb44e,
        0xfb643, 0xfb837, 0xfba4a, 0xfbc3f, 0xfbe53, 0xfc048, 0xfc23c,
        0xfc450, 0xfc645, 0xfc839, 0xfca4c, 0xfcc41, 0xfce36, 0xfd04a,
        0xfd23d, 0xfd451, 0xfd646, 0xfd83a, 0xfda4d, 0xfdc43, 0xfde37,
        0xfe04b, 0xfe23f, 0xfe453, 0xfe648, 0xfe83c, 0xfea4f, 0xfec44,
        0xfee38, 0xff04c, 0xff241, 0xff436, 0xff64a, 0xff83e, 0xffa51,
        0xffc46, 0xffe3a, 0x10004e, 0x100242, 0x100437, 0x10064b, 0x100841,
        0x100a53, 0x100c48, 0x100e3c, 0x10104f, 0x101244, 0x101438,
        0x10164c, 0x101842, 0x101a35, 0x101c49, 0x101e3d, 0x102051,
        0x102245, 0x10243a, 0x10264e, 0x102843, 0x102a37, 0x102c4b,
        0x102e3f, 0x103053, 0x103247, 0x10343b, 0x10364f, 0x103845,
        0x103a38, 0x103c4c, 0x103e42, 0x104036, 0x104249, 0x10443d,
        0x104651, 0x104846, 0x104a3a, 0x104c4e, 0x104e43, 0x105038,
        0x10524a, 0x10543e, 0x105652, 0x105847, 0x105a3b, 0x105c4f,
        0x105e45, 0x106039, 0x10624c, 0x106441, 0x106635, 0x106849,
        0x106a3d, 0x106c51, 0x106e47, 0x10703c, 0x10724f, 0x107444,
        0x107638, 0x10784c, 0x107a3f, 0x107c53, 0x107e48];

    /**
     * @return {number}
     */
    this.GetBitInt = function (data, length, shift) {
        return (data & (((1 << length) - 1) << shift)) >> shift;
    };

    // WARNING: Dates before Oct. 1582 are inaccurate
    /**
     * @return {number}
     */
    this.SolarToInt = function (y, m, d) {
        m = (m + 9) % 12;
        y = parseInt(y) - parseInt(m / 10);
        return 365 * y + parseInt(y / 4) - parseInt(y / 100) + parseInt(y / 400) + parseInt((m * 306 + 5) / 10)
            + (d - 1);
    };

    this.SolarFromInt = function (g) {
        var y = parseInt((10000 * g + 14780) / 3652425);
        var ddd = g - (365 * y + parseInt(y / 4) - parseInt(y / 100) + parseInt(y / 400));
        if (ddd < 0) {
            y--;
            ddd = g - (365 * y + parseInt(y / 4) - parseInt(y / 100) + parseInt(y / 400));
        }
        var mi = parseInt((100 * ddd + 52) / 3060);
        var mm = (mi + 2) % 12 + 1;
        y = y + parseInt((mi + 2) / 12);
        var dd = ddd - parseInt((mi * 306 + 5) / 10) + 1;
        var solar = new Solar();
        solar.solarYear = parseInt(y);
        solar.solarMonth = parseInt(mm);
        solar.solarDay = parseInt(dd);
        return solar;
    };

    this.LunarToSolar = function (lunar) {
        var days = this.lunar_month_days[lunar.lunarYear - this.lunar_month_days[0]];
        var leap = this.GetBitInt(days, 4, 13);
        var offset = 0;
        var loopend = leap;
        if (!lunar.isleap) {
            if (lunar.lunarMonth <= leap || leap == 0) {
                loopend = lunar.lunarMonth - 1;
            } else {
                loopend = lunar.lunarMonth;
            }
        }
        for (var i = 0; i < loopend; i++) {
            offset += this.GetBitInt(days, 1, 12 - i) == 1 ? 30 : 29;
        }
        offset += lunar.lunarDay;

        var solar11 = this.solar_1_1[lunar.lunarYear - this.solar_1_1[0]];

        var y = this.GetBitInt(solar11, 12, 9);
        var m = this.GetBitInt(solar11, 4, 5);
        var d = this.GetBitInt(solar11, 5, 0);

        return this.SolarFromInt(this.SolarToInt(y, m, d) + offset - 1);
    };

    this.SolarToLunar = function (solar) {
        var lunar = new Lunar();
        var index = solar.solarYear - this.solar_1_1[0];
        var data = (solar.solarYear << 9) | (solar.solarMonth << 5)
            | (solar.solarDay);
        if (this.solar_1_1[index] > data) {
            index--;
        }
        var solar11 = this.solar_1_1[index];
        var y = this.GetBitInt(solar11, 12, 9);
        var m = this.GetBitInt(solar11, 4, 5);
        var d = this.GetBitInt(solar11, 5, 0);
        var offset = this.SolarToInt(solar.solarYear, solar.solarMonth,
                solar.solarDay) - this.SolarToInt(y, m, d);

        var days = this.lunar_month_days[index];
        var leap = this.GetBitInt(days, 4, 13);

        var lunarY = index + this.solar_1_1[0];
        var lunarM = 1;
        offset += 1;

        for (var i = 0; i < 13; i++) {
            var dm = this.GetBitInt(days, 1, 12 - i) == 1 ? 30 : 29;
            if (offset > dm) {
                lunarM++;
                offset -= dm;
            } else {
                break;
            }
        }
        var lunarD = parseInt(offset);
        lunar.lunarYear = lunarY;
        lunar.lunarMonth = lunarM;
        lunar.isleap = false;
        if (leap != 0 && lunarM > leap) {
            lunar.lunarMonth = lunarM - 1;
            if (lunarM == leap + 1) {
                lunar.isleap = true;
            }
        }

        lunar.lunarDay = lunarD;
        
        // convert to chinese animal
        lunar.chineseAnimal = this.chinese_animal[(lunarY-1900)%12];
        lunar.chineseCycle = this.cycle10[(lunarY-1144)%10] + this.cycle12[(lunarY-1144)%12];
        
        return lunar;
    }
}