common: define haabMonthDays helper

common/src/mayan.test.ts

@@ -1,7 +1,7 @@
 import {
     formatHaab,
     formatLordOfNight,
-    formatTzolkin,
+    formatTzolkin, HaabMonth, haabMonthDays,
     jdnHaab, jdnHaabExt,
     jdnLordOfNight,
     jdnTzolkin,
@@ -163,6 +163,18 @@ describe('jdnHaab', () => {
     });
 });
 
+describe('haabMonthDays', () => {
+    it('returns 20 days for months 1-18', () => {
+        for (let month = 1; month <= 18; month++) {
+            expect(haabMonthDays(month as HaabMonth)).toBe(20);
+        }
+    });
+
+    it('returns 5 days for month 19 (Wayeb)', () => {
+        expect(haabMonthDays(19)).toBe(5);
+    });
+});
+
 describe('jdnHaabExt', () => {
     it('handles creation correctly', () => {
         expect(jdnHaabExt(583934)).toEqual({year: -1, month: 19, day: 4}); // end of the year before creation

common/src/mayan.ts

@@ -108,8 +108,14 @@ export function jdnHaab(jdn: number): Haab {
     };
 }
 
+export function haabMonthDays(month: HaabMonth): number {
+    return month === 19 ? 5 : 20;
+}
+
+export type HaabYear = number;
+
 export type HaabExt = Haab & {
-    year: number,
+    year: HaabYear,
 };
 
 export function jdnHaabExt(jdn: number): HaabExt {

frcal/src/App.tsx

@@ -1,7 +1,6 @@
 import React from 'react';
 import {Calendar} from './Calendar';
 import {FrenchMonth, frEndJD, frStartJD, frSupportedYear, jdnFrench} from '@common/french';
-import {JulianMonth} from '@common/gregorian';
 import {TimeOfDay} from './TimeOfDay';
 import {GregorianJumper} from '@common/dateJump';
 import MonthBasedApp from '@common/ui/MonthBasedApp';
@@ -11,7 +10,7 @@ export default class App extends MonthBasedApp<number, FrenchMonth> {
     override parseYearMonth(year: string, month: string) {
         if (!frSupportedYear(+year) || +month < 1 || +month > 13)
             return null;
-        return {year: +year, month: +month as JulianMonth};
+        return {year: +year, month: +month as FrenchMonth};
     }
 
     override defaultSelector(todayJDN: number) {