Add Julian calendar handling

common/src/gregorian.test.ts

@@ -1,4 +1,4 @@
-import {gregorianJDN, jdnGregorian} from './gregorian';
+import {gregorianJDN, jdnDate, jdnGregorian, JulianDay, JulianMonth} from './gregorian';
 
 describe('gregorianJDN', () => {
     it('works', () => {
@@ -15,25 +15,55 @@ describe('gregorianJDN', () => {
         expect(gregorianJDN(19720, 8, 14)).toBe(8923868);
         expect(gregorianJDN(7504, 7, 22)).toBe(4462042);
     });
+
+    it('transition to Julian works', () => {
+        expect(gregorianJDN(2000, 1, 1, 2299161)).toBe(2451545);
+        expect(gregorianJDN(1969, 7, 20, 2299161)).toBe(2440423);
+        expect(gregorianJDN(1582, 10, 15, 2299161)).toBe(2299161);
+        expect(gregorianJDN(1582, 10, 4, 2299161)).toBe(2299160);
+        expect(gregorianJDN(1066, 10, 14, 2299161)).toBe(2110701);
+        expect(gregorianJDN(0, 12, 25, 2299161)).toBe(1721417);
+        expect(gregorianJDN(-4712, 1, 1, 2299161)).toBe(0);
+    });
 });
 
 describe('jdnGregorian', () => {
     it('works', () => {
-        expect(jdnGregorian(0)).toEqual(new Date(-4713, 10, 24));
+        function checkJDN(jdn: number, year: number, month: JulianMonth, day: JulianDay) {
-        expect(jdnGregorian(2299160)).toEqual(new Date(1582, 9, 14));
+            expect(jdnGregorian(jdn)).toEqual([year, month, day]);
-        expect(jdnGregorian(2299161)).toEqual(new Date(1582, 9, 15));
+            expect(jdnDate(jdn)).toEqual(new Date(year, month - 1, day));
-        expect(jdnGregorian(2361221)).toEqual(new Date(1752, 8, 13));
+        }
-        expect(jdnGregorian(2361222)).toEqual(new Date(1752, 8, 14));
+
-        expect(jdnGregorian(2451545)).toEqual(new Date(2000, 0, 1));
+        checkJDN(0, -4713, 11, 24);
-        expect(jdnGregorian(-8512316)).toEqual(new Date(-28019, 11, 20));
+        checkJDN(2299160, 1582, 10, 14);
-        expect(jdnGregorian(-8534852)).toEqual(new Date(-28080, 3, 8));
+        checkJDN(2299161, 1582, 10, 15);
-        expect(jdnGregorian(2653462)).toEqual(new Date(2552, 9, 30));
+        checkJDN(2361221, 1752, 9, 13);
-        expect(jdnGregorian(3271156)).toEqual(new Date(4244, 0, 8));
+        checkJDN(2361222, 1752, 9, 14);
-        expect(jdnGregorian(-666477)).toEqual(new Date(-6537, 1, 23));
+        checkJDN(2451545, 2000, 1, 1);
-        expect(jdnGregorian(2397854)).toEqual(new Date(1852, 11, 31));
+        checkJDN(-8512316, -28019, 12, 20);
-        expect(jdnGregorian(-1211235)).toEqual(new Date(-8029, 7, 26));
+        checkJDN(-8534852, -28080, 4, 8);
-        expect(jdnGregorian(-91680)).toEqual(new Date(-4964, 10, 20));
+        checkJDN(2653462, 2552, 10, 30);
-        expect(jdnGregorian(-5605876)).toEqual(new Date(-20061, 6, 14));
+        checkJDN(3271156, 4244, 1, 8);
-        expect(jdnGregorian(-295121)).toEqual(new Date(-5521, 10, 19));
+        checkJDN(-666477, -6537, 2, 23);
+        checkJDN(2397854, 1852, 12, 31);
+        checkJDN(-1211235, -8029, 8, 26);
+        checkJDN(-91680, -4964, 11, 20);
+        checkJDN(-5605876, -20061, 7, 14);
+        checkJDN(-295121, -5521, 11, 19);
+    });
+
+    it('transition to Julian works', () => {
+        function checkJDN(jdn: number, year: number, month: JulianMonth, day: JulianDay) {
+            expect(jdnGregorian(jdn, 2299161)).toEqual([year, month, day]);
+            expect(jdnDate(jdn, 2299161)).toEqual(new Date(year, month - 1, day));
+        }
+
+        checkJDN(2451545, 2000, 1, 1);
+        checkJDN(2440423, 1969, 7, 20);
+        checkJDN(2299161, 1582, 10, 15);
+        checkJDN(2299160, 1582, 10, 4);
+        checkJDN(2110701, 1066, 10, 14);
+        checkJDN(1721417, 0, 12, 25);
+        checkJDN(0, -4712, 1, 1);
     });
 });

common/src/gregorian.ts

@@ -1,21 +1,69 @@
-export function gregorianJDN(year: number, month: number, day: number): number {
+export type JulianMonth = 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12;
+export type JulianDay =
+    | 1
+    | 2
+    | 3
+    | 4
+    | 5
+    | 6
+    | 7
+    | 8
+    | 9
+    | 10
+    | 11
+    | 12
+    | 13
+    | 14
+    | 15
+    | 16
+    | 17
+    | 18
+    | 19
+    | 20
+    | 21
+    | 22
+    | 23
+    | 24
+    | 25
+    | 26
+    | 27
+    | 28
+    | 29
+    | 30
+    | 31;
+
+export type JulianDate = [number, JulianMonth, JulianDay];
+
+export function gregorianJDN(year: number, month: number, day: number, julian_before?: number): number {
     const g = year + 4716 - (month <= 2 ? 1 : 0);
     const f = (month + 9) % 12;
     const e = Math.floor(1461 * g / 4) + day - 1402;
     const J = e + Math.floor((153 * f + 2) / 5);
+
+    if (julian_before != null && J < julian_before)
+        return J;
+
     const dg = 38 - Math.floor(Math.floor((g + 184) / 100) * 3 / 4);
     return J + dg;
 }
 
-export function dateJDN(date: Date) {
+export function dateJDN(date: Date, julian_before?: number) {
-    return gregorianJDN(date.getFullYear(), date.getMonth() + 1, date.getDate());
+    return gregorianJDN(date.getFullYear(), date.getMonth() + 1, date.getDate(), julian_before);
 }
 
-export function jdnGregorian(jdn: number): Date {
+export function jdnGregorian(jdn: number, julian_before?: number): JulianDate {
-    const e = 4 * (jdn + 1401 + Math.floor(Math.floor((4 * jdn + 274277) / 146097) * 3 / 4) - 38) + 3;
+    const dg = julian_before == null || jdn >= julian_before ?
+        Math.floor(Math.floor((4 * jdn + 274277) / 146097) * 3 / 4) - 38 :
+        0;
+    const e = 4 * (jdn + 1401 + dg) + 3;
     const h = 5 * Math.floor((e % 1461 + 1461) % 1461 / 4) + 2;
     const day = Math.floor((h % 153 + 153) % 153 / 5) + 1;
     const month = (Math.floor(h / 153) + 2) % 12 + 1;
     const year = Math.floor(e / 1461) - 4716 + Math.floor((14 - month) / 12);
+    return [year, month as JulianMonth, day as JulianDay];
+}
+
+export function jdnDate(jdn: number, julian_before?: number): Date {
+    const [year, month, day] = jdnGregorian(jdn, julian_before);
     return new Date(year, month - 1, day);
 }

common/src/julian.test.ts

@@ -0,0 +1,25 @@
+import {jdnJulian, julianJDN} from './julian';
+
+describe('gregorianJDN', () => {
+    it('works', () => {
+        expect(julianJDN(2000, 1, 1)).toBe(2451558);
+        expect(julianJDN(1969, 7, 20)).toBe(2440436);
+        expect(julianJDN(1582, 10, 15)).toBe(2299171);
+        expect(julianJDN(1582, 10, 4)).toBe(2299160);
+        expect(julianJDN(1066, 10, 14)).toBe(2110701);
+        expect(julianJDN(0, 12, 25)).toBe(1721417);
+        expect(julianJDN(-4712, 1, 1)).toBe(0);
+    });
+});
+
+describe('jdnGregorian', () => {
+    it('works', () => {
+        expect(jdnJulian(2451558)).toEqual([2000, 1, 1]);
+        expect(jdnJulian(2440436)).toEqual([1969, 7, 20]);
+        expect(jdnJulian(2299171)).toEqual([1582, 10, 15]);
+        expect(jdnJulian(2299160)).toEqual([1582, 10, 4]);
+        expect(jdnJulian(2110701)).toEqual([1066, 10, 14]);
+        expect(jdnJulian(1721417)).toEqual([0, 12, 25]);
+        expect(jdnJulian(0)).toEqual([-4712, 1, 1]);
+    });
+});

common/src/julian.ts

@@ -0,0 +1,9 @@
+import {gregorianJDN, jdnGregorian, JulianDate} from './gregorian';
+
+export function julianJDN(year: number, month: number, day: number): number {
+    return gregorianJDN(year, month, day, Infinity);
+}
+
+export function jdnJulian(jdn: number): JulianDate {
+    return jdnGregorian(jdn, Infinity);
+}

frcal/src/App.tsx

@@ -80,8 +80,8 @@ class App extends React.Component<{}, AppState> {
     }
 
     validYear() {
-        return /^-?\d+$/.test(this.state.goYear) && startGregorian.getFullYear() <= +this.state.goYear &&
+        return /^-?\d+$/.test(this.state.goYear) && startGregorian[0] <= +this.state.goYear &&
-            +this.state.goYear <= endGregorian.getFullYear();
+            +this.state.goYear <= endGregorian[0];
     }
 
     validMonth() {
@@ -112,7 +112,7 @@ class App extends React.Component<{}, AppState> {
 
     onDateChange = (todayJDN: number) => {
         this.setState({todayJDN});
-    }
+    };
 
     render() {
         return <>
@@ -130,7 +130,7 @@ class App extends React.Component<{}, AppState> {
                     <span className="input-group-text">Gregorian<span className="hide-small">&nbsp;Date</span></span>
                     <input type="number" className={`form-control go-year ${this.validYear() ? '' : 'is-invalid'}`}
                            onChange={this.changeField.bind(this, 'goYear')} value={this.state.goYear}
-                           min={startGregorian.getFullYear()} max={endGregorian.getFullYear()}/>
+                           min={startGregorian[0]} max={endGregorian[0]}/>
                     <input type="number" className={`form-control go-month ${this.validMonth() ? '' : 'is-invalid'}`}
                            onChange={this.changeField.bind(this, 'goMonth')} value={this.state.goMonth}
                            min={1} max={12}/>

frcal/src/Calendar.tsx

@@ -13,7 +13,7 @@ import {
     monthName,
     startYear,
 } from '@common/french';
-import {jdnGregorian} from '@common/gregorian';
+import {jdnDate} from '@common/gregorian';
 import {jdnLongCount} from '@common/longCount';
 
 type MonthProps = {
@@ -31,7 +31,7 @@ function DecadeName({name}: { name: string }): JSX.Element {
 
 function DayDetail({jdn}: { jdn: number }): JSX.Element {
     return <div className="DayDetail">
-        <div className="DayDetail-gregorian">{jdnGregorian(jdn).toDateString()}</div>
+        <div className="DayDetail-gregorian">{jdnDate(jdn).toDateString()}</div>
         <div className="DayDetail-lc">{jdnLongCount(jdn)}</div>
     </div>;
 }