simplify per gibson042

spec.html

@@ -36265,6 +36265,7 @@ <h1>
               1. Let _groups_ be *undefined*.
               1. Let _hasGroups_ be *false*.
             1. Perform ! CreateDataPropertyOrThrow(_A_, *"groups"*, _groups_).
+            1. Let _matchedGroupNames_ be a new empty List.
             1. For each integer _i_ such that _i_ &ge; 1 and _i_ &le; _n_, in ascending order, do
               1. Let _captureI_ be _i_<sup>th</sup> element of _r_'s _captures_ List.
               1. If _captureI_ is *undefined*, then
@@ -36282,17 +36283,14 @@ <h1>
               1. Perform ! CreateDataPropertyOrThrow(_A_, ! ToString(𝔽(_i_)), _capturedValue_).
               1. If the _i_<sup>th</sup> capture of _R_ was defined with a |GroupName|, then
                 1. Let _s_ be the CapturingGroupName of that |GroupName|.
-                1. Let _isMatchedEarlier_ be *false*.
-                1. For each integer _j_ such that _j_ &ge; 1 and _j_ &lt; _i_, do
-                  1. If the _j_<sup>th</sup> capture of _R_ was defined with a |GroupName|, then
-                    1. Let _sj_ be the CapturingGroupName of that |GroupName|.
-                    1. If SameValue(_sj_, _s_) is *true* and the _j_<sup>th</sup> element of _r_'s _captures_ List is not *undefined*, set _isMatchedEarlier_ to *true*.
-                1. If _isMatchedEarlier_ is *false*, then
+                1. If _matchedGroupNames_ contains _s_, then
+                  1. Assert: _capturedValue_ is *undefined*.
+                  1. Append *undefined* to _groupNames_.
+                1. Else,
+                  1. If _capturedValue_ is not *undefined*, append _s_ to _matchedGroupNames_.
                   1. NOTE: If there are multiple groups named _s_, _groups_ may already have an _s_ property at this point. However, because _groups_ is an ordinary object whose properties are all writable data properties, the call to CreateDataPropertyOrThrow is nevertheless guaranteed to succeed.
                   1. Perform ! CreateDataPropertyOrThrow(_groups_, _s_, _capturedValue_).
                   1. Append _s_ to _groupNames_.
-                1. Else,
-                  1. Append *undefined* to _groupNames_.
               1. Else,
                 1. Append *undefined* to _groupNames_.
             1. If _hasIndices_ is *true*, then