Normative: Limit offset time zones to minutes

Author: justingrant

polyfill/lib/ecmascript.mjs

@@ -558,8 +558,9 @@ const OFFSET_IDENTIFIER = new RegExp(`^${PARSE.offsetIdentifier.source}$`);
 export function ParseTimeZoneIdentifier(identifier) {
   if (!TIMEZONE_IDENTIFIER.test(identifier)) return undefined;
   if (OFFSET_IDENTIFIER.test(identifier)) {
+    // The regex limits the input to minutes precision
     const { offsetNanoseconds } = ParseUTCOffsetString(identifier);
-    return { offsetNanoseconds };
+    return { offsetMinutes: offsetNanoseconds / 6e10 };
   }
   return { tzName: identifier };
 }
@@ -2096,16 +2097,19 @@ export function ToTemporalTimeZoneSlotValue(temporalTimeZoneLike) {
   const { tzName, offset, z } = ParseTemporalTimeZoneString(identifier);
   if (tzName) {
     // tzName is any valid identifier string in brackets, and could be an offset identifier
-    const { offsetNanoseconds } = ParseTimeZoneIdentifier(tzName);
-    if (offsetNanoseconds !== undefined) return FormatTimeZoneOffsetString(offsetNanoseconds);
+    const { offsetMinutes } = ParseTimeZoneIdentifier(tzName);
+    if (offsetMinutes !== undefined) return FormatTimeZoneOffsetString(offsetMinutes * 6e10);
 
     const record = GetAvailableNamedTimeZoneIdentifier(tzName);
     if (!record) throw new RangeError(`Unrecognized time zone ${tzName}`);
     return record.primaryIdentifier;
   }
   if (z) return 'UTC';
   // if !tzName && !z then offset must be present
-  const { offsetNanoseconds } = ParseUTCOffsetString(offset);
+  const { offsetNanoseconds, hasSubMinutePrecision } = ParseUTCOffsetString(offset);
+  if (hasSubMinutePrecision) {
+    throw new RangeError(`Seconds not allowed in offset time zone: ${offset}`);
+  }
   return FormatTimeZoneOffsetString(offsetNanoseconds);
 }
 

polyfill/lib/regex.mjs

@@ -24,7 +24,7 @@ export const datesplit = new RegExp(
 const timesplit = /(\d{2})(?::(\d{2})(?::(\d{2})(?:[.,](\d{1,9}))?)?|(\d{2})(?:(\d{2})(?:[.,](\d{1,9}))?)?)?/;
 export const offset = /([+\u2212-])([01][0-9]|2[0-3])(?::?([0-5][0-9])(?::?([0-5][0-9])(?:[.,](\d{1,9}))?)?)?/;
 const offsetpart = new RegExp(`([zZ])|${offset.source}?`);
-export const offsetIdentifier = offset;
+export const offsetIdentifier = /([+\u2212-])([01][0-9]|2[0-3])(?::?([0-5][0-9])?)?/;
 export const annotation = /\[(!)?([a-z_][a-z0-9_-]*)=([A-Za-z0-9]+(?:-[A-Za-z0-9]+)*)\]/g;
 
 export const zoneddatetime = new RegExp(

polyfill/lib/timezone.mjs

@@ -28,8 +28,8 @@ export class TimeZone {
     }
     let stringIdentifier = ES.ToString(identifier);
     const parseResult = ES.ParseTimeZoneIdentifier(identifier);
-    if (parseResult?.offsetNanoseconds !== undefined) {
-      stringIdentifier = ES.FormatTimeZoneOffsetString(parseResult.offsetNanoseconds);
+    if (parseResult?.offsetMinutes !== undefined) {
+      stringIdentifier = ES.FormatTimeZoneOffsetString(parseResult.offsetMinutes * 6e10);
     } else {
       const record = ES.GetAvailableNamedTimeZoneIdentifier(stringIdentifier);
       if (!record) throw new RangeError(`Invalid time zone identifier: ${stringIdentifier}`);
@@ -56,8 +56,8 @@ export class TimeZone {
     instant = ES.ToTemporalInstant(instant);
     const id = GetSlot(this, TIMEZONE_ID);
 
-    const offsetNanoseconds = ES.ParseTimeZoneIdentifier(id)?.offsetNanoseconds;
-    if (offsetNanoseconds !== undefined) return offsetNanoseconds;
+    const offsetMinutes = ES.ParseTimeZoneIdentifier(id)?.offsetMinutes;
+    if (offsetMinutes !== undefined) return offsetMinutes * 6e10;
 
     return ES.GetNamedTimeZoneOffsetNanoseconds(id, GetSlot(instant, EPOCHNANOSECONDS));
   }
@@ -85,8 +85,8 @@ export class TimeZone {
     const Instant = GetIntrinsic('%Temporal.Instant%');
     const id = GetSlot(this, TIMEZONE_ID);
 
-    const offsetNanoseconds = ES.ParseTimeZoneIdentifier(id)?.offsetNanoseconds;
-    if (offsetNanoseconds !== undefined) {
+    const offsetMinutes = ES.ParseTimeZoneIdentifier(id)?.offsetMinutes;
+    if (offsetMinutes !== undefined) {
       const epochNs = ES.GetUTCEpochNanoseconds(
         GetSlot(dateTime, ISO_YEAR),
         GetSlot(dateTime, ISO_MONTH),
@@ -99,7 +99,7 @@ export class TimeZone {
         GetSlot(dateTime, ISO_NANOSECOND)
       );
       if (epochNs === null) throw new RangeError('DateTime outside of supported range');
-      return [new Instant(epochNs.minus(offsetNanoseconds))];
+      return [new Instant(epochNs.minus(offsetMinutes * 6e10))];
     }
 
     const possibleEpochNs = ES.GetNamedTimeZoneEpochNanoseconds(

polyfill/test/validStrings.mjs

@@ -262,11 +262,7 @@ const utcOffset = withCode(
   saveOffset
 );
 const timeZoneUTCOffset = choice(utcDesignator, utcOffset);
-const timeZoneUTCOffsetName = seq(
-  sign,
-  hour,
-  choice([minuteSecond, [minuteSecond, [fraction]]], seq(':', minuteSecond, [':', minuteSecond, [fraction]]))
-);
+const timeZoneUTCOffsetName = seq(sign, hour, choice([minuteSecond], seq(':', minuteSecond)));
 const timeZoneIANAName = choice(...timezoneNames);
 const timeZoneIdentifier = withCode(
   choice(timeZoneUTCOffsetName, timeZoneIANAName),

spec/abstractops.html

@@ -1121,7 +1121,7 @@ <h1>ISO 8601 grammar</h1>
           UTCOffsetSubMinutePrecision
 
       TimeZoneUTCOffsetName :
-          UTCOffsetSubMinutePrecision
+          UTCOffsetMinutePrecision
 
       TZLeadingChar :
           Alpha

spec/intl.html

@@ -2543,7 +2543,7 @@ <h1>Temporal.ZonedDateTime.prototype.toLocaleString ( [ _locales_ [ , _options_
             1. Let _dateTimeFormat_ be ! OrdinaryCreateFromConstructor(%DateTimeFormat%, %DateTimeFormat.prototype%, « [[InitializedDateTimeFormat]], [[Locale]], [[Calendar]], [[NumberingSystem]], [[TimeZone]], [[Weekday]], [[Era]], [[Year]], [[Month]], [[Day]], [[DayPeriod]], [[Hour]], [[Minute]], [[Second]], [[FractionalSecondDigits]], [[TimeZoneName]], [[HourCycle]], [[Pattern]], [[BoundFormat]] »).
             1. Let _timeZone_ be ? ToTemporalTimeZoneIdentifier(_zonedDateTime_.[[TimeZone]]).
             1. Let _timeZoneParseResult_ be ParseTimeZoneIdentifier(_timeZone_).
-            1. If _timeZoneParseResult_ is not ~unmatched~ and _timeZoneParseResult_.[[OffsetNanoseconds]] is not ~empty~, throw a *RangeError* exception.
+            1. If _timeZoneParseResult_ is not ~unmatched~ and _timeZoneParseResult_.[[OffsetMinutes]] is not ~empty~, throw a *RangeError* exception.
             1. Let _timeZoneIdentifierRecord_ be GetAvailableNamedTimeZoneIdentifier(_timeZone_).
             1. If _timeZoneIdentifierRecord_ is ~empty~, throw a *RangeError* exception.
             1. Set _timeZone_ to _timeZoneIdentifierRecord_.[[PrimaryIdentifier]].

spec/mainadditions.html

@@ -311,6 +311,8 @@ <h1>Time Zone Offset String <del>Format</del><ins>Formats</ins></h1>
       <ins class="block">
       <p>
         ECMAScript defines string interchange formats for UTC offsets, derived from ISO 8601.
+        UTC offsets that represent offset time zone identifiers, or that are intended for interoperability with ISO 8601, use only hours and minutes and are specified by |UTCOffsetMinutePrecision|.
+        UTC offsets that represent the offset of a named or custom time zone can be more precise, and are specified by |UTCOffsetSubMinutePrecision|.
       </p>
       <p>
         These formats are described by the ISO String grammar in <emu-xref href="#sec-temporal-iso8601grammar"></emu-xref>.

spec/timezone.html

@@ -34,8 +34,8 @@ <h1>Temporal.TimeZone ( _identifier_ )</h1>
         1. Set _identifier_ to ? ToString(_identifier_).
         1. Let _parseResult_ be ParseTimeZoneIdentifier(_identifier_).
         1. If _parseResult_ is ~unmatched~, throw a *RangeError* exception.
-        1. If _parseResult_.[[OffsetNanoseconds]] is not ~empty~, then
-          1. Set _identifier_ to FormatTimeZoneOffsetString(_parseResult_.[[OffsetNanoseconds]]).
+        1. If _parseResult_.[[OffsetMinutes]] is not ~empty~, then
+          1. Set _identifier_ to FormatTimeZoneOffsetString(_parseResult_.[[OffsetMinutes]] × (6 × 10<sup>10</sup>)).
         1. Else,
           1. Let _timeZoneIdentifierRecord_ be GetAvailableNamedTimeZoneIdentifier(_identifier_).
           1. If _timeZoneIdentifierRecord_ is ~empty~, throw a *RangeError* exception.
@@ -102,7 +102,7 @@ <h1>get Temporal.TimeZone.prototype.id</h1>
       <emu-alg>
         1. Let _timeZone_ be the *this* value.
         1. Perform ? RequireInternalSlot(_timeZone_, [[InitializedTemporalTimeZone]]).
-        1. If _timeZone_.[[OffsetNanoseconds]] is not ~empty~, return FormatTimeZoneOffsetString(_timeZone_.[[OffsetNanoseconds]]).
+        1. If _timeZone_.[[OffsetMinutes]] is not ~empty~, return FormatTimeZoneOffsetString(_timeZone_.[[OffsetMinutes]] × (6 × 10<sup>10</sup>)).
         1. Return _timeZone_.[[Identifier]].
       </emu-alg>
     </emu-clause>
@@ -116,7 +116,7 @@ <h1>Temporal.TimeZone.prototype.getOffsetNanosecondsFor ( _instant_ )</h1>
         1. Let _timeZone_ be the *this* value.
         1. Perform ? RequireInternalSlot(_timeZone_, [[InitializedTemporalTimeZone]]).
         1. Set _instant_ to ? ToTemporalInstant(_instant_).
-        1. If _timeZone_.[[OffsetNanoseconds]] is not ~empty~, return 𝔽(_timeZone_.[[OffsetNanoseconds]]).
+        1. If _timeZone_.[[OffsetMinutes]] is not ~empty~, return 𝔽(_timeZone_.[[OffsetMinutes]]).
         1. Return 𝔽(GetNamedTimeZoneOffsetNanoseconds(_timeZone_.[[Identifier]], _instant_.[[Nanoseconds]])).
       </emu-alg>
     </emu-clause>
@@ -172,9 +172,9 @@ <h1>Temporal.TimeZone.prototype.getPossibleInstantsFor ( _dateTime_ )</h1>
         1. Let _timeZone_ be the *this* value.
         1. Perform ? RequireInternalSlot(_timeZone_, [[InitializedTemporalTimeZone]]).
         1. Set _dateTime_ to ? ToTemporalDateTime(_dateTime_).
-        1. If _timeZone_.[[OffsetNanoseconds]] is not ~empty~, then
+        1. If _timeZone_.[[OffsetMinutes]] is not ~empty~, then
           1. Let _epochNanoseconds_ be GetUTCEpochNanoseconds(_dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]]).
-          1. Let _possibleEpochNanoseconds_ be « _epochNanoseconds_ - ℤ(_timeZone_.[[OffsetNanoseconds]]) ».
+          1. Let _possibleEpochNanoseconds_ be « _epochNanoseconds_ - ℤ(_timeZone_.[[OffsetMinutes]] &times; (6 &times; 10<sup>10</sup>)) ».
         1. Else,
           1. Let _possibleEpochNanoseconds_ be GetNamedTimeZoneEpochNanoseconds(_timeZone_.[[Identifier]], _dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]]).
         1. Let _possibleInstants_ be a new empty List.
@@ -195,7 +195,7 @@ <h1>Temporal.TimeZone.prototype.getNextTransition ( _startingPoint_ )</h1>
         1. Let _timeZone_ be the *this* value.
         1. Perform ? RequireInternalSlot(_timeZone_, [[InitializedTemporalTimeZone]]).
         1. Set _startingPoint_ to ? ToTemporalInstant(_startingPoint_).
-        1. If _timeZone_.[[OffsetNanoseconds]] is not ~empty~, return *null*.
+        1. If _timeZone_.[[OffsetMinutes]] is not ~empty~, return *null*.
         1. Let _transition_ be GetNamedTimeZoneNextTransition(_timeZone_.[[Identifier]], _startingPoint_.[[Nanoseconds]]).
         1. If _transition_ is *null*, return *null*.
         1. Return ! CreateTemporalInstant(_transition_).
@@ -211,7 +211,7 @@ <h1>Temporal.TimeZone.prototype.getPreviousTransition ( _startingPoint_ )</h1>
         1. Let _timeZone_ be the *this* value.
         1. Perform ? RequireInternalSlot(_timeZone_, [[InitializedTemporalTimeZone]]).
         1. Set _startingPoint_ to ? ToTemporalInstant(_startingPoint_).
-        1. If _timeZone_.[[OffsetNanoseconds]] is not ~empty~, return *null*.
+        1. If _timeZone_.[[OffsetMinutes]] is not ~empty~, return *null*.
         1. Let _transition_ be GetNamedTimeZonePreviousTransition(_timeZone_.[[Identifier]], _startingPoint_.[[Nanoseconds]]).
         1. If _transition_ is *null*, return *null*.
         1. Return ! CreateTemporalInstant(_transition_).
@@ -226,7 +226,7 @@ <h1>Temporal.TimeZone.prototype.toString ( )</h1>
       <emu-alg>
         1. Let _timeZone_ be the *this* value.
         1. Perform ? RequireInternalSlot(_timeZone_, [[InitializedTemporalTimeZone]]).
-        1. If _timeZone_.[[OffsetNanoseconds]] is not ~empty~, return FormatTimeZoneOffsetString(_timeZone_.[[OffsetNanoseconds]]).
+        1. If _timeZone_.[[OffsetMinutes]] is not ~empty~, return FormatTimeZoneOffsetString(_timeZone_.[[OffsetMinutes]] × (6 × 10<sup>10</sup>)).
         1. Return _timeZone_.[[Identifier]].
       </emu-alg>
     </emu-clause>
@@ -239,7 +239,7 @@ <h1>Temporal.TimeZone.prototype.toJSON ( )</h1>
       <emu-alg>
         1. Let _timeZone_ be the *this* value.
         1. Perform ? RequireInternalSlot(_timeZone_, [[InitializedTemporalTimeZone]]).
-        1. If _timeZone_.[[OffsetNanoseconds]] is not ~empty~, return FormatTimeZoneOffsetString(_timeZone_.[[OffsetNanoseconds]]).
+        1. If _timeZone_.[[OffsetMinutes]] is not ~empty~, return FormatTimeZoneOffsetString(_timeZone_.[[OffsetMinutes]] × (6 × 10<sup>10</sup>)).
         1. Return _timeZone_.[[Identifier]].
       </emu-alg>
     </emu-clause>
@@ -281,11 +281,11 @@ <h1>Properties of Temporal.TimeZone Instances</h1>
           </tr>
           <tr>
             <td>
-              [[OffsetNanoseconds]]
+              [[OffsetMinutes]]
             </td>
             <td>
-              An integer for nanoseconds representing the constant offset of this time zone relative to UTC, or ~empty~ if the instance represents a named time zone.
-              If not ~empty~, this value must be greater than &minus;8.64 &times; 10<sup>13</sup> nanoseconds (&minus;24 hours) and smaller than &plus;8.64 &times; 10<sup>13</sup> nanoseconds (&plus;24 hours).
+              An integer for minutes representing the constant offset of this time zone relative to UTC, or ~empty~ if the instance represents a named time zone.
+              If not ~empty~, this value must be greater than &minus;1440 minutes (&minus;24 hours) and smaller than &plus;1440 minutes (&plus;24 hours).
             </td>
           </tr>
         </tbody>
@@ -322,18 +322,18 @@ <h1>
       </dl>
       <emu-alg>
         1. If _newTarget_ is not present, set _newTarget_ to %Temporal.TimeZone%.
-        1. Let _object_ be ? OrdinaryCreateFromConstructor(_newTarget_, *"%Temporal.TimeZone.prototype%"*, « [[InitializedTemporalTimeZone]], [[Identifier]], [[OffsetNanoseconds]] »).
+        1. Let _object_ be ? OrdinaryCreateFromConstructor(_newTarget_, *"%Temporal.TimeZone.prototype%"*, « [[InitializedTemporalTimeZone]], [[Identifier]], [[OffsetMinutes]] »).
         1. Assert: _identifier_ is an available named time zone identifier or an offset time zone identifier.
         1. Let _parseResult_ be ParseTimeZoneIdentifier(_identifier_).
         1. Assert: _parseResult_ is not ~unmatched~.
-        1. If _parseResult_.[[OffsetNanoseconds]] is not ~empty~, then
+        1. If _parseResult_.[[OffsetMinutes]] is not ~empty~, then
           1. Set _object_.[[Identifier]] to ~empty~.
-          1. Set _object_.[[OffsetNanoseconds]] to _parseResult_.[[OffsetNanoseconds]].
+          1. Set _object_.[[OffsetMinutes]] to _parseResult_.[[OffsetMinutes]].
         1. Else,
           1. Assert: _parseResult_.[[Name]] is not ~empty~.
           1. Assert: GetAvailableNamedTimeZoneIdentifier(_identifier_).[[PrimaryIdentifier]] is _identifier_.
           1. Set _object_.[[Identifier]] to _identifier_.
-          1. Set _object_.[[OffsetNanoseconds]] to ~empty~.
+          1. Set _object_.[[OffsetMinutes]] to ~empty~.
         1. Return _object_.
       </emu-alg>
 
@@ -344,7 +344,7 @@ <h1>
           Although the [[Identifier]] internal slot is a String in this specification, implementations may choose to store named time zone identifiers it in any other form (for example as an enumeration or index into a List of identifier strings) as long as the String can be regenerated when needed.
         </p>
         <p>
-          Similar flexibility exists for the storage of the [[OffsetNanoseconds]] internal slot, which can be interchangeably represented as a 6-byte integer or as a String value that may be as long as 19 characters.
+          Similar flexibility exists for the storage of the [[OffsetMinutes]] internal slot, which can be interchangeably represented as a 12-bit integer or as a 6-character ±HH:MM string.
           ParseTimeZoneIdentifier and FormatTimeZoneOffsetString may be used to losslessly convert one representation to the other.
           Implementations are free to store either or both representations.
         </p>
@@ -563,8 +563,8 @@ <h1>
         1. Let _parseResult_ be ? ParseTemporalTimeZoneString(_identifier_).
         1. If _parseResult_.[[Name]] is not *undefined*, then
           1. Let _name_ be _parseResult_.[[Name]].
-          1. Let _offsetNanoseconds_ be ParseTimeZoneIdentifier(_name_).[[OffsetNanoseconds]].
-          1. If _offsetNanoseconds_ is not ~empty~, return FormatTimeZoneOffsetString(_offsetNanoseconds_).
+          1. Let _offsetMinutes_ be ParseTimeZoneIdentifier(_name_).[[OffsetMinutes]].
+          1. If _offsetMinutes_ is not ~empty~, return FormatTimeZoneOffsetString(_offsetMinutes_ × (6 × 10<sup>10</sup>)).
           1. Let _timeZoneIdentifierRecord_ be GetAvailableNamedTimeZoneIdentifier(_name_).
           1. If _timeZoneIdentifierRecord_ is ~empty~, throw a *RangeError* exception.
           1. Return _timeZoneIdentifierRecord_.[[PrimaryIdentifier]].
@@ -815,13 +815,13 @@ <h1>
       <h1>
         ParseTimeZoneIdentifier (
           _identifier_: a String
-        ): a Record containing [[Name]] and [[OffsetNanoseconds]] fields, or ~unmatched~
+        ): a Record containing [[Name]] and [[OffsetMinutes]] fields, or ~unmatched~
       </h1>
       <dl class="header">
         <dt>description</dt>
         <dd>
-          If _identifier_ is an available named time zone identifier, [[Name]] will be _identifier_ and [[OffsetNanoseconds]] will be ~empty~.
-          If _identifier_ is an offset time zone identifier, [[Name]] will be ~empty~ and [[OffsetNanoseconds]] will be a signed integer.
+          If _identifier_ is an available named time zone identifier, [[Name]] will be _identifier_ and [[OffsetMinutes]] will be ~empty~.
+          If _identifier_ is an offset time zone identifier, [[Name]] will be ~empty~ and [[OffsetMinutes]] will be a signed integer.
           Otherwise, ~unmatched~ will be returned.
         </dd>
       </dl>
@@ -830,13 +830,13 @@ <h1>
         1. If _parseResult_ is a List of errors, return ~unmatched~.
         1. If _parseResult_ contains a |TimeZoneIANAName| Parse Node, then
           1. Let _name_ be the source text matched by the |TimeZoneIANAName| Parse Node contained within _parseResult_.
-          1. Return the Record { [[Name]]: _name_, [[OffsetNanoseconds]]: ~empty~ }.
+          1. Return the Record { [[Name]]: _name_, [[OffsetMinutes]]: ~empty~ }.
         1. Else,
           1. Assert: _parseResult_ contains a |TimeZoneUTCOffsetName| Parse Node.
           1. Let _offsetString_ be the source text matched by the |TimeZoneUTCOffsetName| Parse Node contained within _parseResult_.
           1. Let _offsetNanoseconds_ be ParseUTCOffsetString(_offsetString_).
           1. Assert: _offsetNanoseconds_ modulo 6 &times; 10<sup>10</sup> = 0.
-          1. Return the Record { [[Name]]: ~empty~, [[OffsetNanoseconds]]: _offsetNanoseconds_ }.
+          1. Return the Record { [[Name]]: ~empty~, [[OffsetMinutes]]: _offsetNanoseconds_ / (6 &times; 10<sup>10</sup>) }.
       </emu-alg>
     </emu-clause>
   </emu-clause>