Normative: Drop support for sub-minute UTC offsets

spec/datetimeformat.html

@@ -95,8 +95,13 @@ <h1>
         1. Else,
           1. Set _timeZone_ to ? ToString(_timeZone_).
         1. If IsTimeZoneOffsetString(_timeZone_) is *true*, then
+          1. Let _parseResult_ be ParseText(StringToCodePoints(_timeZone_), |UTCOffset|).
+          1. Assert: _parseResult_ is a Parse Node.
+          1. If _parseResult_ contains more than one |MinuteSecond| Parse Node, throw a *RangeError* exception.
           1. Let _offsetNanoseconds_ be ParseTimeZoneOffsetString(_timeZone_).
-          1. Set _timeZone_ to FormatTimeZoneOffsetString(_offsetNanoseconds_).
+          1. Let _offsetMinutes_ be _offsetNanoseconds_ / (6 × 10<sup>10</sup>).
+          1. Assert: _offsetMinutes_ is an integer.
+          1. Set _timeZone_ to FormatOffsetTimeZoneIdentifier(_offsetMinutes_).
         1. Else if IsValidTimeZoneName(_timeZone_) is *true*, then
           1. Set _timeZone_ to CanonicalizeTimeZoneName(_timeZone_).
         1. Else,
@@ -169,28 +174,24 @@ <h1>
       </emu-alg>
     </emu-clause>
 
-    <emu-clause id="sec-formattimezoneoffsetstring" aoid="FormatTimeZoneOffsetString">
-      <h1>FormatTimeZoneOffsetString ( _offsetNanoseconds_ )</h1>
+    <emu-clause id="sec-formatoffsettimezoneidentifier" type="abstract operation">
+      <h1>
+        FormatOffsetTimeZoneIdentifier (
+          _offsetMinutes_: an integer,
+        ): a String
+      </h1>
+      <dl class="header">
+        <dt>description</dt>
+        <dd>
+          It formats a UTC offset, in minutes, into a UTC offset string formatted like ±HH:MM.
+        </dd>
+      </dl>
       <emu-alg>
-        1. Assert: _offsetNanoseconds_ is an integer.
-        1. If _offsetNanoseconds_ &ge; 0, let _sign_ be the code unit 0x002B (PLUS SIGN); otherwise, let _sign_ be the code unit 0x002D (HYPHEN-MINUS).
-        1. Set _offsetNanoseconds_ to abs(_offsetNanoseconds_).
-        1. Let _nanoseconds_ be _offsetNanoseconds_ modulo 10<sup>9</sup>.
-        1. Let _seconds_ be floor(_offsetNanoseconds_ / 10<sup>9</sup>) modulo 60.
-        1. Let _minutes_ be floor(_offsetNanoseconds_ / (6 &times; 10<sup>10</sup>)) modulo 60.
-        1. Let _hours_ be floor(_offsetNanoseconds_ / (3.6 &times; 10<sup>12</sup>)).
-        1. Let _h_ be ToZeroPaddedDecimalString(_hours_, 2).
-        1. Let _m_ be ToZeroPaddedDecimalString(_minutes_, 2).
-        1. Let _s_ be ToZeroPaddedDecimalString(_seconds_, 2).
-        1. If _nanoseconds_ &ne; 0, then
-          1. Let _fraction_ be ToZeroPaddedDecimalString(_nanoseconds_, 9).
-          1. Set _fraction_ to the longest possible substring of _fraction_ starting at position 0 and not ending with the code unit 0x0030 (DIGIT ZERO).
-          1. Let _post_ be the string-concatenation of the code unit 0x003A (COLON), _s_, the code unit 0x002E (FULL STOP), and _fraction_.
-        1. Else if seconds &ne; 0, then
-          1. Let _post_ be the string-concatenation of the code unit 0x003A (COLON) and _s_.
-        1. Else,
-          1. Let _post_ be the empty String.
-        1. Return the string-concatenation of _sign_, _h_, the code unit 0x003A (COLON), _m_, and _post_.
+        1. If _offsetMinutes_ &ge; 0, let _sign_ be the code unit 0x002B (PLUS SIGN); otherwise, let _sign_ be the code unit 0x002D (HYPHEN-MINUS).
+        1. Let _absoluteMinutes_ be abs(_offsetMinutes_).
+        1. Let _hours_ be floor(_absoluteMinutes_ / 60).
+        1. Let _minutes_ be _absoluteMinutes_ modulo 60.
+        1. Return the string-concatenation of _sign_, ToZeroPaddedDecimalString(_hours_, 2), the code unit 0x003A (COLON), and ToZeroPaddedDecimalString(_minutes_, 2).
       </emu-alg>
     </emu-clause>
   </emu-clause>