Refactor CalendarDate to return AnyCalendarDate type

packages/@internationalized/date/src/CalendarDate.ts

@@ -40,8 +40,6 @@ function shiftArgs(args: any[]) {
 /** A CalendarDate represents a date without any time components in a specific calendar system. */
 export class CalendarDate {
   // This prevents TypeScript from allowing other types with the same fields to match.
-  // i.e. a ZonedDateTime should not be be passable to a parameter that expects CalendarDate.
-  // If that behavior is desired, use the AnyCalendarDate interface instead.
   // @ts-ignore
   #type;
   /** The calendar system associated with this date, e.g. Gregorian. */
@@ -76,13 +74,11 @@ export class CalendarDate {
       second: 0,
       millisecond: 0
     });
-
-    this.calendar = calendar;
+    this.calendar = normalized.calendar;
     this.era = normalized.era;
     this.year = normalized.year;
     this.month = normalized.month;
     this.day = normalized.day;
-
     constrain(this);
   }
 
@@ -251,7 +247,7 @@ export class CalendarDateTime {
       millisecond
     });
 
-    this.calendar = calendar;
+    this.calendar = normalized.calendar;
     this.era = normalized.era;
     this.year = normalized.year;
     this.month = normalized.month;
@@ -260,7 +256,6 @@ export class CalendarDateTime {
     this.minute = normalized.minute;
     this.second = normalized.second;
     this.millisecond = normalized.millisecond;
-
     constrain(this);
   }
 
@@ -372,7 +367,7 @@ export class ZonedDateTime {
 
     const normalized = normalize({
       calendar,
-      era: era,
+      era,
       year,
       month,
       day,
@@ -382,8 +377,8 @@ export class ZonedDateTime {
       millisecond
     });
 
-    this.calendar = calendar;
-    this.era = era;
+    this.calendar = normalized.calendar;
+    this.era = normalized.era;
     this.year = normalized.year;
     this.month = normalized.month;
     this.day = normalized.day;
@@ -393,7 +388,6 @@ export class ZonedDateTime {
     this.minute = normalized.minute;
     this.second = normalized.second;
     this.millisecond = normalized.millisecond;
-
     constrain(this);
   }
 

packages/@internationalized/date/src/calendars/BuddhistCalendar.ts

@@ -27,15 +27,17 @@ const BUDDHIST_ERA_START = -543;
 export class BuddhistCalendar extends GregorianCalendar {
   identifier = 'buddhist';
 
-  fromJulianDay(jd: number): CalendarDate {
+  fromJulianDay(jd: number): AnyCalendarDate {
     let gregorianDate = super.fromJulianDay(jd);
     let year = getExtendedYear(gregorianDate.era, gregorianDate.year);
-    return new CalendarDate(
-      this,
-      year - BUDDHIST_ERA_START,
-      gregorianDate.month,
-      gregorianDate.day
-    );
+
+    return {
+      calendar: this,
+      era: 'BE',  // Buddhist Era
+      year: year - BUDDHIST_ERA_START,
+      month: gregorianDate.month,
+      day: gregorianDate.day
+    };
   }
 
   toJulianDay(date: AnyCalendarDate) {

packages/@internationalized/date/src/calendars/GregorianCalendar.ts

@@ -14,7 +14,6 @@
 // Original licensing can be found in the NOTICE file in the root directory of this source tree.
 
 import {AnyCalendarDate, Calendar} from '../types';
-import {CalendarDate} from '../CalendarDate';
 import {mod, Mutable} from '../utils';
 
 const EPOCH = 1721426; // 001/01/03 Julian C.E.
@@ -70,7 +69,7 @@ const daysInMonth = {
 export class GregorianCalendar implements Calendar {
   identifier = 'gregory';
 
-  fromJulianDay(jd: number): CalendarDate {
+  fromJulianDay(jd: number): AnyCalendarDate {
     let jd0 = jd;
     let depoch = jd0 - EPOCH;
     let quadricent = Math.floor(depoch / 146097);
@@ -93,7 +92,13 @@ export class GregorianCalendar implements Calendar {
     let month = Math.floor(((yearDay + leapAdj) * 12 + 373) / 367);
     let day = jd0 - gregorianToJulianDay(era, year, month, 1) + 1;
 
-    return new CalendarDate(era, year, month, day);
+    return {
+      calendar: this,
+      era,
+      year,
+      month,
+      day
+    };
   }
 
   toJulianDay(date: AnyCalendarDate): number {

packages/@internationalized/date/src/calendars/IndianCalendar.ts

@@ -14,7 +14,6 @@
 // Original licensing can be found in the NOTICE file in the root directory of this source tree.
 
 import {AnyCalendarDate} from '../types';
-import {CalendarDate} from '../CalendarDate';
 import {fromExtendedYear, GregorianCalendar, gregorianToJulianDay, isLeapYear} from './GregorianCalendar';
 
 // Starts in 78 AD,
@@ -31,7 +30,7 @@ const INDIAN_YEAR_START = 80;
 export class IndianCalendar extends GregorianCalendar {
   identifier = 'indian';
 
-  fromJulianDay(jd: number): CalendarDate {
+  fromJulianDay(jd: number): AnyCalendarDate {
     // Gregorian date for Julian day
     let date = super.fromJulianDay(jd);
 
@@ -71,8 +70,15 @@ export class IndianCalendar extends GregorianCalendar {
         indianDay = (mDay % 30) + 1;
       }
     }
-
-    return new CalendarDate(this, indianYear, indianMonth, indianDay);
+    const eras = this.getEras();
+    const era = eras[eras.length - 1];
+    return {
+      calendar: this,
+      era: era,
+      year: indianYear,
+      month: indianMonth,
+      day: indianDay
+    };
   }
 
   toJulianDay(date: AnyCalendarDate) {

packages/@internationalized/date/src/calendars/JapaneseCalendar.ts

@@ -57,11 +57,13 @@ function toGregorian(date: AnyCalendarDate) {
     throw new Error('Unknown era: ' + date.era);
   }
 
-  return new CalendarDate(
-    date.year + eraAddend,
-    date.month,
-    date.day
-  );
+  return {
+    era: 'AD',
+    year: date.year + eraAddend,
+    month: date.month,
+    day: date.day,
+    calendar: new GregorianCalendar()
+  };
 }
 
 /**

packages/@internationalized/date/src/calendars/PersianCalendar.ts

@@ -14,7 +14,6 @@
 // Original licensing can be found in the NOTICE file in the root directory of this source tree.
 
 import {AnyCalendarDate, Calendar} from '../types';
-import {CalendarDate} from '../CalendarDate';
 import {mod} from '../utils';
 
 const PERSIAN_EPOCH = 1948320;
@@ -44,7 +43,7 @@ const MONTH_START = [
 export class PersianCalendar implements Calendar {
   identifier = 'persian';
 
-  fromJulianDay(jd: number): CalendarDate {
+  fromJulianDay(jd: number): AnyCalendarDate {
     let daysSinceEpoch = jd - PERSIAN_EPOCH;
     let year = 1 + Math.floor((33 * daysSinceEpoch + 3) / 12053);
     let farvardin1 = 365 * (year - 1) + Math.floor((8 * year + 21) / 33);
@@ -53,7 +52,14 @@ export class PersianCalendar implements Calendar {
       ? Math.floor(dayOfYear / 31)
       : Math.floor((dayOfYear - 6) / 30);
     let day = dayOfYear - MONTH_START[month] + 1;
-    return new CalendarDate(this, year, month + 1, day);
+
+    return {
+      calendar: this,
+      era: 'AP',  // Anno Persico/Persian Era
+      year,
+      month: month + 1,
+      day
+    };
   }
 
   toJulianDay(date: AnyCalendarDate): number {

packages/@internationalized/date/src/calendars/TaiwanCalendar.ts

@@ -79,10 +79,11 @@ export class TaiwanCalendar extends GregorianCalendar {
 
 function toGregorian(date: AnyCalendarDate) {
   let [era, year] = fromExtendedYear(gregorianYear(date));
-  return new CalendarDate(
-    era,
-    year,
-    date.month,
-    date.day
-  );
+  return {
+    era: era,
+    year: year,
+    month: date.month,
+    day: date.day,
+    calendar: new GregorianCalendar()
+  };
 }

packages/@internationalized/date/src/conversion.ts

@@ -13,14 +13,14 @@
 // Portions of the code in this file are based on code from the TC39 Temporal proposal.
 // Original licensing can be found in the NOTICE file in the root directory of this source tree.
 
-import {AnyCalendarDate, AnyDateTime, AnyTime, Calendar, DateFields, Disambiguation, TimeFields} from './types';
+import {AnyCalendarDate, AnyDateTime, AnyTime, Calendar, Copyable, DateFields, Disambiguation, TimeFields} from './types';
 import {CalendarDate, CalendarDateTime, Time, ZonedDateTime} from './CalendarDate';
 import {constrain} from './manipulation';
 import {getExtendedYear, GregorianCalendar} from './calendars/GregorianCalendar';
 import {getLocalTimeZone} from './queries';
 import {Mutable} from './utils';
 
-export function epochFromDate(date: AnyDateTime) {
+export function epochFromDate(date: AnyDateTime & Copyable) {
   date = toCalendar(date, new GregorianCalendar());
   let year = getExtendedYear(date.era, date.year);
   return epochFromParts(year, date.month, date.day, date.hour, date.minute, date.second, date.millisecond);
@@ -259,7 +259,7 @@ export function toTime(dateTime: CalendarDateTime | ZonedDateTime): Time {
 }
 
 /** Converts a date from one calendar system to another. */
-export function toCalendar<T extends AnyCalendarDate>(date: T, calendar: Calendar): T {
+export function toCalendar<T extends AnyCalendarDate & Copyable>(date: T, calendar: Calendar): T {
   if (date.calendar.identifier === calendar.identifier) {
     return date;
   }