Editorial: Simplify {date,time}Style vs. explicit component checking

Author: gibson042

spec/datetimeformat.html

@@ -85,6 +85,7 @@ <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ )</h1>
           1. Set _timeZone_ to ! CanonicalizeTimeZoneName(_timeZone_).
         1. Set _dateTimeFormat_.[[TimeZone]] to _timeZone_.
         1. Let _formatOptions_ be a new Record.
+        1. Let _hasExplicitFormatComponents_ be *false*.
         1. For each row of <emu-xref href="#table-datetimeformat-components"></emu-xref>, except the header row, in table order, do
           1. Let _prop_ be the name given in the Property column of the row.
           1. If _prop_ is *"fractionalSecondDigits"*, then
@@ -93,6 +94,7 @@ <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ )</h1>
             1. Let _values_ be a List whose elements are the strings given in the Values column of the row.
             1. Let _value_ be ? GetOption(_options_, _prop_, *"string"*, _values_, *undefined*).
           1. Set _formatOptions_.[[&lt;_prop_&gt;]] to _value_.
+          1. If _value_ is not *undefined*, set _hasExplicitFormatComponents_ to *true*.
         1. Let _dataLocaleData_ be _localeData_.[[&lt;_dataLocale_&gt;]].
         1. Let _hcDefault_ be _dataLocaleData_.[[hourCycle]].
         1. Let _hc_ be _dateTimeFormat_.[[HourCycle]].
@@ -118,10 +120,7 @@ <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ )</h1>
         1. Let _timeStyle_ be ? GetOption(_options_, *"timeStyle"*, *"string"*, &laquo; *"full"*, *"long"*, *"medium"*, *"short"* &raquo;, *undefined*).
         1. Set _dateTimeFormat_.[[TimeStyle]] to _timeStyle_.
         1. If _dateStyle_ is not *undefined* or _timeStyle_ is not *undefined*, then
-          1. For each row in <emu-xref href="#table-datetimeformat-components"></emu-xref>, except the header row, do
-            1. Let _prop_ be the name given in the Property column of the row.
-            1. If _formatOptions_.[[&lt;_prop_&gt;]] is present and its value is not *undefined*, then
-              1. Throw a *TypeError* exception.
+          1. If _hasExplicitFormatComponents_ is *true*, throw a *TypeError* exception.
           1. Let _styles_ be _dataLocaleData_.[[styles]].[[&lt;_calendar_&gt;]].
           1. Let _bestFormat_ be DateTimeStyleFormat(_dateStyle_, _timeStyle_, _styles_).
         1. Else,