Specify ZonedDateTime.toPlain{YearMonth,MonthDay}()

And make a small adjustment to the polyfill to match. See: #569
tc39 · Nov 10, 2020 · 5d5ca83 · 5d5ca83
1 parent db24ae7
commit 5d5ca83
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Showing 2 changed files with 16 additions and 6 deletions.
diff --git a/polyfill/lib/zoneddatetime.mjs b/polyfill/lib/zoneddatetime.mjs
@@ -657,16 +657,16 @@ export class ZonedDateTime {
     if (!ES.IsTemporalZonedDateTime(this)) throw new TypeError('invalid receiver');
     const YearMonth = GetIntrinsic('%Temporal.PlainYearMonth%');
     const calendar = GetSlot(this, CALENDAR);
-    const fieldNames = ES.CalendarFields(calendar, ['day', 'month', 'year']);
-    const fields = ES.ToTemporalDateFields(this, fieldNames);
+    const fieldNames = ES.CalendarFields(calendar, ['month', 'year']);
+    const fields = ES.ToTemporalYearMonthFields(this, fieldNames);
     return calendar.yearMonthFromFields(fields, {}, YearMonth);
   }
   toPlainMonthDay() {
     if (!ES.IsTemporalZonedDateTime(this)) throw new TypeError('invalid receiver');
     const MonthDay = GetIntrinsic('%Temporal.PlainMonthDay%');
     const calendar = GetSlot(this, CALENDAR);
-    const fieldNames = ES.CalendarFields(calendar, ['day', 'month', 'year']);
-    const fields = ES.ToTemporalDateFields(this, fieldNames);
+    const fieldNames = ES.CalendarFields(calendar, ['day', 'month']);
+    const fields = ES.ToTemporalMonthDayFields(this, fieldNames);
     return calendar.monthDayFromFields(fields, {}, MonthDay);
   }
   getFields() {

diff --git a/spec/zoneddatetime.html b/spec/zoneddatetime.html
@@ -908,7 +908,12 @@ <h1>Temporal.ZonedDateTime.prototype.toPlainYearMonth ( )</h1>
         1. Let _timeZone_ be _zonedDateTime_.[[TimeZone]].
         1. Let _instant_ be ? CreateTemporalInstant(_zonedDateTime_.[[Nanoseconds]]).
         1. Let _temporalDateTime_ be ? GetTemporalDateTimeFor(_timeZone_, _instant_).
-        1. Return ? <mark>create via `calendar.yearMonthFromFields()`</mark>.
+        1. Let _calendar_ be _zonedDateTime_.[[Calendar]].
+        1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"month"*, *"year"* »).
+        1. Let _fields_ be ? ToTemporalYearMonthFields(_temporalDateTime_, _fieldNames_).
+        1. Let _yearMonthFromFields_ be ? Get(_calendar_, *"yearMonthFromFields"*).
+        1. Let _options_ be ? OrdinaryObjectCreate(%Object.prototype%).
+        1. Return ? Call(_yearMonthFromFields_, _calendar_, « _fields_, _options_, %Temporal.PlainMonthDay% »).
       </emu-alg>
     </emu-clause>
 
@@ -923,7 +928,12 @@ <h1>Temporal.ZonedDateTime.prototype.toPlainMonthDay ( )</h1>
         1. Let _timeZone_ be _zonedDateTime_.[[TimeZone]].
         1. Let _instant_ be ? CreateTemporalInstant(_zonedDateTime_.[[Nanoseconds]]).
         1. Let _temporalDateTime_ be ? GetTemporalDateTimeFor(_timeZone_, _instant_).
-        1. Return ? <mark>create via `calendar.monthDayFromFields()`</mark>.
+        1. Let _calendar_ be _zonedDateTime_.[[Calendar]].
+        1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"month"* »).
+        1. Let _fields_ be ? ToTemporalMonthDayFields(_temporalDateTime_, _fieldNames_).
+        1. Let _monthDayFromFields_ be ? Get(_calendar_, *"monthDayFromFields"*).
+        1. Let _options_ be ? OrdinaryObjectCreate(%Object.prototype%).
+        1. Return ? Call(_monthDayFromFields_, _calendar_, « _fields_, _options_, %Temporal.PlainMonthDay% »).
       </emu-alg>
     </emu-clause>