Set didExpandCalendarUnit in the two 'special cases' where years and months are increased

Author: catamorphism

polyfill/lib/ecmascript.mjs

@@ -3224,6 +3224,7 @@ function NudgeToCalendarUnit(
   // Create a duration with smallestUnit trunc'd towards zero
   // Create a separate duration that incorporates roundingIncrement
   let r1, r2, startDuration, endDuration;
+  var didExpandCalendarUnit = false;
   const compare = (d1, d2) => CompareDurations(d1, d2, undefined, ToTemporalDate(isoDateTime.isoDate), unit, unit);
   switch (unit) {
     case 'year': {
@@ -3235,6 +3236,7 @@ function NudgeToCalendarUnit(
       var cmpResult = compare(CombineDateAndTimeDuration(endDuration, TimeDuration.ZERO),
                               duration);
       if ((sign > 0 && cmpResult != 1) || (sign < 0 && cmpResult != -1)) {
+        didExpandCalendarUnit = true;
         r1 = r2;
         r2 = years + (increment * 2) * sign;
         endDuration = { ...endDuration, years: r2 };
@@ -3254,6 +3256,7 @@ function NudgeToCalendarUnit(
       var cmpResult = compare(CombineDateAndTimeDuration(endDuration, TimeDuration.ZERO),
                               duration);
       if ((sign > 0 && cmpResult != 1) || (sign < 0 && cmpResult != -1)) {
+        didExpandCalendarUnit = true;
         r1 = r2;
         r2 = months + (increment * 2) * sign;
         endDuration = AdjustDateDurationRecord(duration.date, 0, 0, r2);
@@ -3297,7 +3300,7 @@ function NudgeToCalendarUnit(
     // If the start of the bound is the same as the "origin" (aka relativeTo),
     // use the origin's epoch-nanoseconds as-is instead of relying on isoDateTime,
     // which then gets zoned and converted back to epoch-nanoseconds,
-    // which looses precision and creates a distorted bounding window.
+    // which loses precision and creates a distorted bounding window.
     startEpochNs = originEpochNs;
   } else {
     const start = CalendarDateAdd(calendar, isoDateTime.isoDate, startDuration, 'constrain');
@@ -3335,7 +3338,7 @@ function NudgeToCalendarUnit(
   assert(MathAbs(r1) <= MathAbs(total) && MathAbs(total) <= MathAbs(r2), 'r1 ≤ total ≤ r2');
 
   // Determine whether expanded or contracted
-  const didExpandCalendarUnit = roundedUnit === MathAbs(r2);
+  didExpandCalendarUnit |= roundedUnit === MathAbs(r2);
   duration = { date: didExpandCalendarUnit ? endDuration : startDuration, time: TimeDuration.ZERO };
 
   const nudgeResult = {