Allow timeZone.getPossibleInstantsFor() to return an iterable

The getPossibleInstantsFor() methods of the built-in Temporal time zones will only ever return arrays, but this allows custom time zones to return an iterable (such as a Set.) See: #1427
tc39 · Apr 16, 2021 · e3e680b · e3e680b
1 parent 1670ebd
commit e3e680b
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Showing 2 changed files with 4 additions and 3 deletions.
diff --git a/polyfill/lib/ecmascript.mjs b/polyfill/lib/ecmascript.mjs
@@ -1496,7 +1496,7 @@ export const ES = ObjectAssign({}, ES2020, {
     }
 
     // "prefer" or "reject"
-    const possibleInstants = timeZone.getPossibleInstantsFor(dt);
+    const possibleInstants = ES.GetPossibleInstantsFor(timeZone, dt);
     for (const candidate of possibleInstants) {
       const candidateOffset = ES.GetOffsetNanosecondsFor(timeZone, candidate);
       if (candidateOffset === offsetNs) return GetSlot(candidate, EPOCHNANOSECONDS);
@@ -2051,7 +2051,7 @@ export const ES = ObjectAssign({}, ES2020, {
   GetPossibleInstantsFor: (timeZone, dateTime) => {
     let getPossibleInstantsFor = ES.GetMethod(timeZone, 'getPossibleInstantsFor');
     const possibleInstants = ES.Call(getPossibleInstantsFor, timeZone, [dateTime]);
-    const result = ES.CreateListFromArrayLike(possibleInstants, ['Object']);
+    const result = [...possibleInstants];
     const numInstants = result.length;
     for (let ix = 0; ix < numInstants; ix++) {
       if (!ES.IsTemporalInstant(result[ix])) {
@@ -3844,6 +3844,7 @@ export const ES = ObjectAssign({}, ES2020, {
   },
   MoveRelativeDate: (calendar, relativeTo, duration) => {
     const later = ES.CalendarDateAdd(calendar, relativeTo, duration, {});
+    relativeTo = ES.ToTemporalDateTime(relativeTo);
     const days = ES.DaysUntil(relativeTo, later);
     relativeTo = ES.CreateTemporalDateTime(
       GetSlot(later, ISO_YEAR),

diff --git a/spec/timezone.html b/spec/timezone.html
@@ -626,7 +626,7 @@ <h1>BuiltinTimeZoneGetInstantFor ( _timeZone_, _dateTime_, _disambiguation_ )</h
       <h1>GetPossibleInstantsFor ( _timeZone_, _dateTime_ )</h1>
       <emu-alg>
         1. Let _possibleInstants_ be ? Invoke(_timeZone_, *"getPossibleInstantsFor"*, « _dateTime_ »).
-        1. Let _list_ be ? CreateListFromArrayLike(_possibleInstants_, « Object »).
+        1. Let _list_ be ? IterableToList(_possibleInstants_).
         1. For each element _instant_ in _list_ in List order, do
           1. Perform ? RequireInternalSlot(_instant_, [[InitializedTemporalInstant]]).
         1. Return _list_.