Update polyfill

polyfill/lib/calendar.mjs

@@ -2,6 +2,8 @@
 
 import * as ES from './ecmascript.mjs';
 import { GetIntrinsic, MakeIntrinsicClass, DefineIntrinsic } from './intrinsicclass.mjs';
+import ToString from 'es-abstract/2022/ToString.js';
+import ToIntegerOrInfinity from 'es-abstract/2022/ToIntegerOrInfinity.js';
 import {
   CALENDAR_ID,
   ISO_YEAR,
@@ -306,11 +308,10 @@ impl['iso8601'] = {
     if (fields.month !== undefined && fields.year === undefined && fields.monthCode === undefined) {
       throw new TypeError('either year or monthCode required with month');
     }
-    const useYear = fields.monthCode === undefined;
     const referenceISOYear = 1972;
     fields = resolveNonLunisolarMonth(fields);
     let { month, day, year } = fields;
-    ({ month, day } = ES.RegulateISODate(useYear ? year : referenceISOYear, month, day, overflow));
+    ({ month, day } = ES.RegulateISODate(year !== undefined ? year : referenceISOYear, month, day, overflow));
     return ES.CreateTemporalMonthDay(month, day, calendarSlotValue, referenceISOYear);
   },
   fields(fields) {
@@ -1921,10 +1922,21 @@ const helperDangi = ObjectAssign({}, { ...helperChinese, id: 'dangi' });
  * ISO and non-ISO implementations vs. code that was very different.
  */
 const nonIsoGeneralImpl = {
+  CalendarFieldDescriptors(type) {
+    let fieldDescriptors = [];
+    if (type !== 'month-day') {
+      fieldDescriptors = [
+        { property: 'era', conversion: ToString, required: false },
+        { property: 'eraYear', conversion: ToIntegerOrInfinity, required: false }
+      ];
+    }
+    return fieldDescriptors;
+  },
   dateFromFields(fields, options, calendarSlotValue) {
     const cache = new OneObjectCache();
     const fieldNames = this.fields(['day', 'month', 'monthCode', 'year']);
-    fields = ES.PrepareTemporalFields(fields, fieldNames, []);
+    const extraFieldDescriptors = this.CalendarFieldDescriptors('date');
+    fields = ES.PrepareTemporalFields(fields, fieldNames, [], '', extraFieldDescriptors);
     const overflow = ES.ToTemporalOverflow(options);
     const { year, month, day } = this.helper.calendarToIsoDate(fields, overflow, cache);
     const result = ES.CreateTemporalDate(year, month, day, calendarSlotValue);
@@ -1934,7 +1946,8 @@ const nonIsoGeneralImpl = {
   yearMonthFromFields(fields, options, calendarSlotValue) {
     const cache = new OneObjectCache();
     const fieldNames = this.fields(['month', 'monthCode', 'year']);
-    fields = ES.PrepareTemporalFields(fields, fieldNames, []);
+    const extraFieldDescriptors = this.CalendarFieldDescriptors('year-month');
+    fields = ES.PrepareTemporalFields(fields, fieldNames, [], '', extraFieldDescriptors);
     const overflow = ES.ToTemporalOverflow(options);
     const { year, month, day } = this.helper.calendarToIsoDate({ ...fields, day: 1 }, overflow, cache);
     const result = ES.CreateTemporalYearMonth(year, month, calendarSlotValue, /* referenceISODay = */ day);
@@ -1946,7 +1959,8 @@ const nonIsoGeneralImpl = {
     // For lunisolar calendars, either `monthCode` or `year` must be provided
     // because `month` is ambiguous without a year or a code.
     const fieldNames = this.fields(['day', 'month', 'monthCode', 'year']);
-    fields = ES.PrepareTemporalFields(fields, fieldNames, []);
+    const extraFieldDescriptors = this.CalendarFieldDescriptors('date');
+    fields = ES.PrepareTemporalFields(fields, fieldNames, [], '', extraFieldDescriptors);
     const overflow = ES.ToTemporalOverflow(options);
     const { year, month, day } = this.helper.monthDayFromFields(fields, overflow, cache);
     // `year` is a reference year where this month/day exists in this calendar

polyfill/lib/ecmascript.mjs

@@ -3,6 +3,7 @@
 const ArrayIncludes = Array.prototype.includes;
 const ArrayPrototypePush = Array.prototype.push;
 const ArrayPrototypeSort = Array.prototype.sort;
+const ArrayPrototypeFind = Array.prototype.find;
 const IntlDateTimeFormat = globalThis.Intl.DateTimeFormat;
 const MathMin = Math.min;
 const MathMax = Math.max;
@@ -164,8 +165,6 @@ const BUILTIN_CASTS = new Map([
   ['milliseconds', ToIntegerIfIntegral],
   ['microseconds', ToIntegerIfIntegral],
   ['nanoseconds', ToIntegerIfIntegral],
-  ['era', ToString],
-  ['eraYear', ToIntegerOrInfinity],
   ['offset', ToString]
 ]);
 
@@ -1060,10 +1059,20 @@ export function PrepareTemporalFields(
   bag,
   fields,
   requiredFields,
-  { emptySourceErrorMessage = 'no supported properties found' } = {}
+  { emptySourceErrorMessage = 'no supported properties found' } = {},
+  extraFieldDescriptors = []
 ) {
   const result = ObjectCreate(null);
   let any = false;
+  if (extraFieldDescriptors) {
+    for (let index = 0; index < extraFieldDescriptors.length; index++) {
+      let desc = extraFieldDescriptors[index];
+      Call(ArrayPrototypePush, fields, [desc.property]);
+      if (desc.required === true && requiredFields !== 'partial') {
+        Call(ArrayPrototypePush, requiredFields, [desc.property]);
+      }
+    }
+  }
   Call(ArrayPrototypeSort, fields, []);
   for (let index = 0; index < fields.length; index++) {
     const property = fields[index];
@@ -1072,6 +1081,14 @@ export function PrepareTemporalFields(
       any = true;
       if (BUILTIN_CASTS.has(property)) {
         value = BUILTIN_CASTS.get(property)(value);
+      } else if (extraFieldDescriptors) {
+        const matchingDescriptor = Call(ArrayPrototypeFind, extraFieldDescriptors, [
+          (desc) => desc.property === property
+        ]);
+        if (matchingDescriptor) {
+          const convertor = matchingDescriptor.conversion;
+          value = convertor(value);
+        }
       }
       result[property] = value;
     } else if (requiredFields !== 'partial') {