spec: use "contains" and assertion verbage (#23)

Author: ljharb

index.html

@@ -2309,7 +2309,7 @@ <h1><span class="secnum">2.3</span>
         <var>value</var>: an ECMAScript language value,
       )
     </h1>
-    <emu-alg><ol><li>For each <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> { [[Key]], [[Elements]] } <var>g</var> of <var>groups</var>, do<ol><li>If !&nbsp;<emu-xref aoid="SameValueZero" id="_ref_17"><a href="https://tc39.es/ecma262/#sec-samevaluezero">SameValueZero</a></emu-xref>(<var>g</var>.[[Key]], <var>key</var>) is <emu-val>true</emu-val>, then<ol><li>Append <var>value</var> as the last element of <var>g</var>.[[Elements]].</li><li>Return.</li></ol></li></ol></li><li>Let <var>elements</var> be a <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">List</a></emu-xref> whose sole element is <var>value</var>.</li><li>Let <var>group</var> be the <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> { [[Key]]: <var>key</var>, [[Elements]]: <var>elements</var> }.</li><li>Append <var>group</var> as the last element of <var>groups</var>.</li></ol></emu-alg>
+    <emu-alg><ol><li>If <var>groups</var> contains a <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> <var>g</var> such that !&nbsp;<emu-xref aoid="SameValueZero" id="_ref_17"><a href="https://tc39.es/ecma262/#sec-samevaluezero">SameValueZero</a></emu-xref>(<var>g</var>.[[Key]], <var>key</var>) is <emu-val>true</emu-val>, then<ol><li><emu-xref href="#assert"><a href="https://tc39.es/ecma262/#assert">Assert</a></emu-xref>: exactly one element of <var>groups</var> meets this criteria.</li><li>Append <var>value</var> as the last element of <var>g</var>.[[Elements]].</li></ol></li><li>Else,<ol><li>Let <var>group</var> be the <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> { [[Key]]: <var>key</var>, [[Elements]]: « <var>value</var> » }.</li><li>Append <var>group</var> as the last element of <var>groups</var>.</li></ol></li></ol></emu-alg>
   </emu-clause>
   </ins>
 </emu-clause><emu-annex id="sec-copyright-and-software-license">

spec.emu

@@ -103,13 +103,12 @@ location: https://tc39.es/proposal-array-grouping/
       )
     </h1>
     <emu-alg>
-        1. For each Record { [[Key]], [[Elements]] } _g_ of _groups_, do
-          1. If ! SameValueZero(_g_.[[Key]], _key_) is *true*, then
-            1. Append _value_ as the last element of _g_.[[Elements]].
-            1. Return.
-        1. Let _elements_ be a List whose sole element is _value_.
-        1. Let _group_ be the Record { [[Key]]: _key_, [[Elements]]: _elements_ }.
-        1. Append _group_ as the last element of _groups_.
+        1. If _groups_ contains a Record _g_ such that ! SameValueZero(_g_.[[Key]], _key_) is *true*, then
+          1. Assert: exactly one element of _groups_ meets this criteria.
+          1. Append _value_ as the last element of _g_.[[Elements]].
+        1. Else,
+          1. Let _group_ be the Record { [[Key]]: _key_, [[Elements]]: &laquo; _value_ &raquo; }.
+          1. Append _group_ as the last element of _groups_.
     </emu-alg>
   </emu-clause>
   </ins>