From 45377b2e717ba8528d019c449dfb4828bbaa9041 Mon Sep 17 00:00:00 2001
From: Justin Ridgewell <justin@ridgewell.name>
Date: Tue, 29 Nov 2022 14:25:48 -0500
Subject: [PATCH] Review updates

---
 index.html | 22 ++++++++--------------
 spec.emu   | 25 ++++++++++---------------
 2 files changed, 18 insertions(+), 29 deletions(-)

diff --git a/index.html b/index.html
index e7b9b31..dc3de30 100644
--- a/index.html
+++ b/index.html
@@ -1149,7 +1149,7 @@
 });
 
 let sdoMap = JSON.parse(`{}`);
-let biblio = JSON.parse(`{"refsByClause":{"sec-object.groupby":["_ref_0","_ref_1","_ref_2"],"sec-map.groupby":["_ref_3","_ref_4","_ref_5","_ref_6","_ref_7","_ref_8","_ref_9"],"sec-group-by":["_ref_10","_ref_11","_ref_12","_ref_13","_ref_14","_ref_15","_ref_16","_ref_17","_ref_18","_ref_19","_ref_20","_ref_21"],"sec-add-value-to-keyed-group":["_ref_22"]},"entries":[{"type":"clause","id":"sec-scope","titleHTML":"Scope","number":"1"},{"type":"clause","id":"sec-object.groupby","title":"Object.groupBy ( items, callbackfn )","titleHTML":"Object.groupBy ( <var>items</var>, <var>callbackfn</var> )","number":"2.1"},{"type":"clause","id":"sec-properties-of-the-object-constructor","titleHTML":"Properties of the Object Constructor (20.1.2)","number":"2"},{"type":"clause","id":"sec-map.groupby","title":"Map.groupBy ( items, callbackfn )","titleHTML":"Map.groupBy ( <var>items</var>, <var>callbackfn</var> )","number":"3.1"},{"type":"clause","id":"sec-properties-of-the-map-constructor","titleHTML":"Properties of the Map Constructor (24.1.2)","number":"3"},{"type":"op","aoid":"GroupBy","refId":"sec-group-by"},{"type":"clause","id":"sec-group-by","title":"GroupBy ( items, callbackfn, coercion )","titleHTML":"GroupBy ( <var>items</var>, <var>callbackfn</var>, <var>coercion</var> )","number":"4.1","referencingIds":["_ref_0","_ref_7"]},{"type":"op","aoid":"AddValueToKeyedGroup","refId":"sec-add-value-to-keyed-group"},{"type":"clause","id":"sec-add-value-to-keyed-group","title":"AddValueToKeyedGroup ( groups, key, value )","titleHTML":"AddValueToKeyedGroup ( <var>groups</var>, <var>key</var>, <var>value</var> )","number":"4.2","referencingIds":["_ref_21"]},{"type":"clause","id":"sec-group-by-helpers","titleHTML":"Group By Helpers","number":"4"},{"type":"clause","id":"sec-copyright-and-software-license","title":"Copyright & Software License","titleHTML":"Copyright &amp; Software License","number":"A"}]}`);
+let biblio = JSON.parse(`{"refsByClause":{"sec-object.groupby":["_ref_0","_ref_1","_ref_2"],"sec-map.groupby":["_ref_3","_ref_4","_ref_5"],"sec-group-by":["_ref_6","_ref_7","_ref_8","_ref_9","_ref_10","_ref_11","_ref_12","_ref_13","_ref_14","_ref_15","_ref_16","_ref_17","_ref_18"],"sec-add-value-to-keyed-group":["_ref_19"]},"entries":[{"type":"clause","id":"sec-scope","titleHTML":"Scope","number":"1"},{"type":"clause","id":"sec-object.groupby","title":"Object.groupBy ( items, callbackfn )","titleHTML":"Object.groupBy ( <var>items</var>, <var>callbackfn</var> )","number":"2.1"},{"type":"clause","id":"sec-properties-of-the-object-constructor","titleHTML":"Properties of the Object Constructor (20.1.2)","number":"2"},{"type":"clause","id":"sec-map.groupby","title":"Map.groupBy ( items, callbackfn )","titleHTML":"Map.groupBy ( <var>items</var>, <var>callbackfn</var> )","number":"3.1"},{"type":"clause","id":"sec-properties-of-the-map-constructor","titleHTML":"Properties of the Map Constructor (24.1.2)","number":"3"},{"type":"op","aoid":"GroupBy","refId":"sec-group-by"},{"type":"clause","id":"sec-group-by","title":"GroupBy ( items, callbackfn, coercion )","titleHTML":"GroupBy ( <var>items</var>, <var>callbackfn</var>, <var>coercion</var> )","number":"4.1","referencingIds":["_ref_0","_ref_3"]},{"type":"op","aoid":"AddValueToKeyedGroup","refId":"sec-add-value-to-keyed-group"},{"type":"clause","id":"sec-add-value-to-keyed-group","title":"AddValueToKeyedGroup ( groups, key, value )","titleHTML":"AddValueToKeyedGroup ( <var>groups</var>, <var>key</var>, <var>value</var> )","number":"4.2","referencingIds":["_ref_18"]},{"type":"clause","id":"sec-group-by-helpers","titleHTML":"Group By Helpers","number":"4"},{"type":"clause","id":"sec-copyright-and-software-license","title":"Copyright & Software License","titleHTML":"Copyright &amp; Software License","number":"A"}]}`);
 ;let usesMultipage = false</script><style>body {
   display: flex;
   font-size: 18px;
@@ -2429,16 +2429,13 @@ <h1><span class="secnum">2</span> Properties of the Object Constructor (<a href=
   <ins class="block">
   <emu-clause id="sec-object.groupby">
     <h1><span class="secnum">2.1</span> Object.groupBy ( <var>items</var>, <var>callbackfn</var> )</h1>
-    <emu-note><span class="note">Note 1</span><div class="note-contents">
+    <emu-note><span class="note">Note</span><div class="note-contents">
       <p><var>callbackfn</var> should be a function that accepts two arguments. <code>groupBy</code> calls <var>callbackfn</var> once for each element in <var>items</var>, in ascending order, and constructs a new Object of arrays. Each value returned by <var>callbackfn</var> is coerced to a property key, and the associated element is included in the array in the constructed object according to this property key.</p>
       <p><var>callbackfn</var> is called with two arguments: the value of the element and the index of the element.</p>
       <p>The return value of <code>groupBy</code> is an object that does not inherit from %Object.prototype%.</p>
     </div></emu-note>
     <p>When the <code>groupBy</code> method is called with two or three arguments, the following steps are taken:</p>
-    <emu-alg><ol><li>Let <var>obj</var> be OrdinaryObjectCreate(<emu-val>null</emu-val>).</li><li>Let <var>groups</var> be ?&nbsp;<emu-xref aoid="GroupBy" id="_ref_0"><a href="#sec-group-by">GroupBy</a></emu-xref>(<var>items</var>, <var>callbackfn</var>, <emu-const>property</emu-const>).</li><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>Let <var>elements</var> be <emu-xref aoid="CreateArrayFromList" id="_ref_1"><a href="https://tc39.es/ecma262/#sec-createarrayfromlist">CreateArrayFromList</a></emu-xref>(<var>g</var>.[[Elements]]).</li><li>Perform ?&nbsp;<emu-xref aoid="CreateDataPropertyOrThrow" id="_ref_2"><a href="https://tc39.es/ecma262/#sec-createdatapropertyorthrow">CreateDataPropertyOrThrow</a></emu-xref>(<var>obj</var>, <var>g</var>.[[Key]], <var>elements</var>).</li></ol></li><li>Return <var>obj</var>.</li></ol></emu-alg>
-    <emu-note><span class="note">Note 2</span><div class="note-contents">
-      <p>This method is an intentionally generic factory method; it does not require that its this value be the Object <emu-xref href="#constructor"><a href="https://tc39.es/ecma262/#constructor">constructor</a></emu-xref>. Therefore it can be transferred to or inherited by any other constructors that have no arguments.</p>
-    </div></emu-note>
+    <emu-alg><ol><li>Let <var>groups</var> be ?&nbsp;<emu-xref aoid="GroupBy" id="_ref_0"><a href="#sec-group-by">GroupBy</a></emu-xref>(<var>items</var>, <var>callbackfn</var>, <emu-const>property</emu-const>).</li><li>Let <var>obj</var> be OrdinaryObjectCreate(<emu-val>null</emu-val>).</li><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>Let <var>elements</var> be <emu-xref aoid="CreateArrayFromList" id="_ref_1"><a href="https://tc39.es/ecma262/#sec-createarrayfromlist">CreateArrayFromList</a></emu-xref>(<var>g</var>.[[Elements]]).</li><li>Perform ?&nbsp;<emu-xref aoid="CreateDataPropertyOrThrow" id="_ref_2"><a href="https://tc39.es/ecma262/#sec-createdatapropertyorthrow">CreateDataPropertyOrThrow</a></emu-xref>(<var>obj</var>, <var>g</var>.[[Key]], <var>elements</var>).</li></ol></li><li>Return <var>obj</var>.</li></ol></emu-alg>
   </emu-clause>
   </ins>
 </emu-clause>
@@ -2449,16 +2446,13 @@ <h1><span class="secnum">3</span> Properties of the Map Constructor (<a href="ht
   <ins class="block">
   <emu-clause id="sec-map.groupby">
     <h1><span class="secnum">3.1</span> Map.groupBy ( <var>items</var>, <var>callbackfn</var> )</h1>
-    <emu-note><span class="note">Note 1</span><div class="note-contents">
+    <emu-note><span class="note">Note</span><div class="note-contents">
       <p><var>callbackfn</var> should be a function that accepts two arguments. <code>groupBy</code> calls <var>callbackfn</var> once for each element in <var>items</var>, in ascending order, and constructs a new Map of arrays. Each value returned by <var>callbackfn</var> is used as a key in the Map, and the associated element is included in the array in the constructed Map according to this key.</p>
       <p><var>callbackfn</var> is called with two arguments: the value of the element and the index of the element.</p>
       <p>The return value of <code>groupBy</code> is a Map.</p>
     </div></emu-note>
     <p>When the <code>groupBy</code> method is called with two or three arguments, the following steps are taken:</p>
-    <emu-alg><ol><li>Let <var>C</var> be the <emu-val>this</emu-val> value.</li><li>If <emu-xref aoid="IsConstructor" id="_ref_3"><a href="https://tc39.es/ecma262/#sec-isconstructor">IsConstructor</a></emu-xref>(<var>C</var>) is <emu-val>false</emu-val>, throw a <emu-val>TypeError</emu-val> exception.</li><li>Let <var>map</var> be ?&nbsp;<emu-xref aoid="Construct" id="_ref_4"><a href="https://tc39.es/ecma262/#sec-construct">Construct</a></emu-xref>(<var>C</var>).</li><li>Let <var>adder</var> be ?&nbsp;<emu-xref aoid="Get" id="_ref_5"><a href="https://tc39.es/ecma262/#sec-get-o-p">Get</a></emu-xref>(<var>map</var>, <emu-val>"set"</emu-val>).</li><li>If <emu-xref aoid="IsCallable" id="_ref_6"><a href="https://tc39.es/ecma262/#sec-iscallable">IsCallable</a></emu-xref>(<var>adder</var>) is <emu-val>false</emu-val>, throw a <emu-val>TypeError</emu-val> exception.</li><li>Let <var>groups</var> be ?&nbsp;<emu-xref aoid="GroupBy" id="_ref_7"><a href="#sec-group-by">GroupBy</a></emu-xref>(<var>items</var>, <var>callbackfn</var>, <emu-const>none</emu-const>).</li><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>Let <var>elements</var> be <emu-xref aoid="CreateArrayFromList" id="_ref_8"><a href="https://tc39.es/ecma262/#sec-createarrayfromlist">CreateArrayFromList</a></emu-xref>(<var>g</var>.[[Elements]]).</li><li>Perform ?&nbsp;<emu-xref aoid="Call" id="_ref_9"><a href="https://tc39.es/ecma262/#sec-call">Call</a></emu-xref>(<var>adder</var>, <var>map</var>, « <var>g</var>.[[Key]], <var>elements</var> »).</li></ol></li><li>Return <var>map</var>.</li></ol></emu-alg>
-    <emu-note><span class="note">Note 2</span><div class="note-contents">
-      <p>This method is an intentionally generic factory method; it does not require that its this value be the Map <emu-xref href="#constructor"><a href="https://tc39.es/ecma262/#constructor">constructor</a></emu-xref>. Therefore it can be transferred to or inherited by any other constructors that have no arguments.</p>
-    </div></emu-note>
+    <emu-alg><ol><li>Let <var>groups</var> be ?&nbsp;<emu-xref aoid="GroupBy" id="_ref_3"><a href="#sec-group-by">GroupBy</a></emu-xref>(<var>items</var>, <var>callbackfn</var>, <emu-const>zero</emu-const>).</li><li>Let <var>map</var> be !&nbsp;<emu-xref aoid="Construct" id="_ref_4"><a href="https://tc39.es/ecma262/#sec-construct">Construct</a></emu-xref>(<emu-xref href="#sec-map-constructor"><a href="https://tc39.es/ecma262/#sec-map-constructor">%Map%</a></emu-xref>).</li><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>Let <var>elements</var> be <emu-xref aoid="CreateArrayFromList" id="_ref_5"><a href="https://tc39.es/ecma262/#sec-createarrayfromlist">CreateArrayFromList</a></emu-xref>(<var>g</var>.[[Elements]]).</li><li>Let <var>entry</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>g</var>.[[Key]], [[Value]]: <var>elements</var> }.</li><li>Append <var>entry</var> as the last element of <var>map</var>.[[MapData]].</li></ol></li><li>Return <var>map</var>.</li></ol></emu-alg>
   </emu-clause>
   </ins>
 </emu-clause>
@@ -2469,8 +2463,8 @@ <h1><span class="secnum">4</span> Group By Helpers</h1>
   <ins class="block">
   <emu-clause id="sec-group-by" type="abstract operation" aoid="GroupBy">
     <h1><span class="secnum">4.1</span> GroupBy ( <var>items</var>, <var>callbackfn</var>, <var>coercion</var> )</h1>
-    <p>The abstract operation GroupBy takes arguments <var>items</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), <var>callbackfn</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), and <var>coercion</var> (<emu-const>none</emu-const> or <emu-const>property</emu-const>) and returns either a normal completion containing 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> of Records with fields [[Key]] (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and [[Elements]] (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> of ECMAScript language values), or a throw completion. It performs the following steps when called:</p>
-    <emu-alg><ol><li>If <emu-xref aoid="IsCallable" id="_ref_10"><a href="https://tc39.es/ecma262/#sec-iscallable">IsCallable</a></emu-xref>(<var>callbackfn</var>) is <emu-val>false</emu-val>, throw a <emu-val>TypeError</emu-val> exception.</li><li>Let <var>groups</var> be a new empty <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>.</li><li>Let <var>iteratorRecord</var> be ?&nbsp;<emu-xref aoid="GetIterator" id="_ref_11"><a href="https://tc39.es/ecma262/#sec-getiterator">GetIterator</a></emu-xref>(<var>items</var>).</li><li>Let <var>k</var> be 0.</li><li>Repeat,<ol><li>If <var>k</var> ≥ 2<sup>53</sup> - 1, then<ol><li>Let <var>error</var> be <emu-xref aoid="ThrowCompletion" id="_ref_12"><a href="https://tc39.es/ecma262/#sec-throwcompletion">ThrowCompletion</a></emu-xref>(a newly created <emu-val>TypeError</emu-val> object).</li><li>Return ?&nbsp;<emu-xref aoid="IteratorClose" id="_ref_13"><a href="https://tc39.es/ecma262/#sec-iteratorclose">IteratorClose</a></emu-xref>(<var>iteratorRecord</var>, <var>error</var>).</li></ol></li><li>Let <var>Pk</var> be !&nbsp;<emu-xref aoid="ToString" id="_ref_14"><a href="https://tc39.es/ecma262/#sec-tostring">ToString</a></emu-xref>(<emu-xref href="#𝔽"><a href="https://tc39.es/ecma262/#𝔽">𝔽</a></emu-xref>(<var>k</var>)).</li><li>Let <var>next</var> be ?&nbsp;<emu-xref aoid="IteratorStep" id="_ref_15"><a href="https://tc39.es/ecma262/#sec-iteratorstep">IteratorStep</a></emu-xref>(<var>iteratorRecord</var>).</li><li>If <var>next</var> is <emu-val>false</emu-val>, then<ol><li>Return <var>groups</var>.</li></ol></li><li>Let <var>value</var> be ?&nbsp;<emu-xref aoid="IteratorValue" id="_ref_16"><a href="https://tc39.es/ecma262/#sec-iteratorvalue">IteratorValue</a></emu-xref>(<var>next</var>).</li><li>Let <var>key</var> be <emu-xref aoid="Completion" id="_ref_17"><a href="https://tc39.es/ecma262/#sec-completion-record-specification-type">Completion</a></emu-xref>(<emu-xref aoid="Call" id="_ref_18"><a href="https://tc39.es/ecma262/#sec-call">Call</a></emu-xref>(<var>callbackfn</var>, <emu-val>undefined</emu-val>, « <var>value</var>, <emu-xref href="#𝔽"><a href="https://tc39.es/ecma262/#𝔽">𝔽</a></emu-xref>(<var>k</var>) »)).</li><li>IfAbruptCloseIterator(<var>key</var>, <var>iteratorRecord</var>).</li><li>If <var>coercion</var> is <emu-const>property</emu-const>, then<ol><li>Set <var>key</var> to <emu-xref aoid="Completion" id="_ref_19"><a href="https://tc39.es/ecma262/#sec-completion-record-specification-type">Completion</a></emu-xref>(<emu-xref aoid="ToPropertyKey" id="_ref_20"><a href="https://tc39.es/ecma262/#sec-topropertykey">ToPropertyKey</a></emu-xref>(<var>key</var>)).</li><li>IfAbruptCloseIterator(<var>key</var>, <var>iteratorRecord</var>).</li></ol></li><li>Perform <emu-xref aoid="AddValueToKeyedGroup" id="_ref_21"><a href="#sec-add-value-to-keyed-group">AddValueToKeyedGroup</a></emu-xref>(<var>groups</var>, <var>key</var>, <var>value</var>).</li><li>Set <var>k</var> to <var>k</var> + 1.</li></ol></li></ol></emu-alg>
+    <p>The abstract operation GroupBy takes arguments <var>items</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), <var>callbackfn</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), and <var>coercion</var> (<emu-const>property</emu-const> or <emu-const>zero</emu-const>) and returns either a normal completion containing 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> of Records with fields [[Key]] (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and [[Elements]] (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> of ECMAScript language values), or a throw completion. It performs the following steps when called:</p>
+    <emu-alg><ol><li>Perform ?&nbsp;<emu-xref aoid="RequireObjectCoercible" id="_ref_6"><a href="https://tc39.es/ecma262/#sec-requireobjectcoercible">RequireObjectCoercible</a></emu-xref>(<var>items</var>).</li><li>If <emu-xref aoid="IsCallable" id="_ref_7"><a href="https://tc39.es/ecma262/#sec-iscallable">IsCallable</a></emu-xref>(<var>callbackfn</var>) is <emu-val>false</emu-val>, throw a <emu-val>TypeError</emu-val> exception.</li><li>Let <var>groups</var> be a new empty <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>.</li><li>Let <var>iteratorRecord</var> be ?&nbsp;<emu-xref aoid="GetIterator" id="_ref_8"><a href="https://tc39.es/ecma262/#sec-getiterator">GetIterator</a></emu-xref>(<var>items</var>).</li><li>Let <var>k</var> be 0.</li><li>Repeat,<ol><li>If <var>k</var> ≥ 2<sup>53</sup> - 1, then<ol><li>Let <var>error</var> be <emu-xref aoid="ThrowCompletion" id="_ref_9"><a href="https://tc39.es/ecma262/#sec-throwcompletion">ThrowCompletion</a></emu-xref>(a newly created <emu-val>TypeError</emu-val> object).</li><li>Return ?&nbsp;<emu-xref aoid="IteratorClose" id="_ref_10"><a href="https://tc39.es/ecma262/#sec-iteratorclose">IteratorClose</a></emu-xref>(<var>iteratorRecord</var>, <var>error</var>).</li></ol></li><li>Let <var>Pk</var> be !&nbsp;<emu-xref aoid="ToString" id="_ref_11"><a href="https://tc39.es/ecma262/#sec-tostring">ToString</a></emu-xref>(<emu-xref href="#𝔽"><a href="https://tc39.es/ecma262/#𝔽">𝔽</a></emu-xref>(<var>k</var>)).</li><li>Let <var>next</var> be ?&nbsp;<emu-xref aoid="IteratorStep" id="_ref_12"><a href="https://tc39.es/ecma262/#sec-iteratorstep">IteratorStep</a></emu-xref>(<var>iteratorRecord</var>).</li><li>If <var>next</var> is <emu-val>false</emu-val>, then<ol><li>Return <var>groups</var>.</li></ol></li><li>Let <var>value</var> be ?&nbsp;<emu-xref aoid="IteratorValue" id="_ref_13"><a href="https://tc39.es/ecma262/#sec-iteratorvalue">IteratorValue</a></emu-xref>(<var>next</var>).</li><li>Let <var>key</var> be <emu-xref aoid="Completion" id="_ref_14"><a href="https://tc39.es/ecma262/#sec-completion-record-specification-type">Completion</a></emu-xref>(<emu-xref aoid="Call" id="_ref_15"><a href="https://tc39.es/ecma262/#sec-call">Call</a></emu-xref>(<var>callbackfn</var>, <emu-val>undefined</emu-val>, « <var>value</var>, <emu-xref href="#𝔽"><a href="https://tc39.es/ecma262/#𝔽">𝔽</a></emu-xref>(<var>k</var>) »)).</li><li>IfAbruptCloseIterator(<var>key</var>, <var>iteratorRecord</var>).</li><li>If <var>coercion</var> is <emu-const>property</emu-const>, then<ol><li>Set <var>key</var> to <emu-xref aoid="Completion" id="_ref_16"><a href="https://tc39.es/ecma262/#sec-completion-record-specification-type">Completion</a></emu-xref>(<emu-xref aoid="ToPropertyKey" id="_ref_17"><a href="https://tc39.es/ecma262/#sec-topropertykey">ToPropertyKey</a></emu-xref>(<var>key</var>)).</li><li>IfAbruptCloseIterator(<var>key</var>, <var>iteratorRecord</var>).</li></ol></li><li>Else,<ol><li><emu-xref href="#assert"><a href="https://tc39.es/ecma262/#assert">Assert</a></emu-xref>: <var>coercion</var> is <emu-const>zero</emu-const>.</li><li>If <var>key</var> is <emu-val>-0</emu-val><sub>𝔽</sub>, set <var>key</var> to <emu-val>+0</emu-val><sub>𝔽</sub>.</li></ol></li><li>Perform <emu-xref aoid="AddValueToKeyedGroup" id="_ref_18"><a href="#sec-add-value-to-keyed-group">AddValueToKeyedGroup</a></emu-xref>(<var>groups</var>, <var>key</var>, <var>value</var>).</li><li>Set <var>k</var> to <var>k</var> + 1.</li></ol></li></ol></emu-alg>
   </emu-clause>
   </ins>
 
@@ -2478,7 +2472,7 @@ <h1><span class="secnum">4.1</span> GroupBy ( <var>items</var>, <var>callbackfn<
   <emu-clause id="sec-add-value-to-keyed-group" type="abstract operation" aoid="AddValueToKeyedGroup">
     <h1><span class="secnum">4.2</span> AddValueToKeyedGroup ( <var>groups</var>, <var>key</var>, <var>value</var> )</h1>
     <p>The abstract operation AddValueToKeyedGroup takes arguments <var>groups</var> (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> of Records that have [[Key]] and [[Elements]] fields), <var>key</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), and <var>value</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and returns <emu-const>unused</emu-const>. It performs the following steps when called:</p>
-    <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 <emu-xref aoid="SameValue" id="_ref_22"><a href="https://tc39.es/ecma262/#sec-samevalue">SameValue</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><li>Return <emu-const>unused</emu-const>.</li></ol></li></ol></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>value</var> » }.</li><li>Append <var>group</var> as the last element of <var>groups</var>.</li><li>Return <emu-const>unused</emu-const>.</li></ol></emu-alg>
+    <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 <emu-xref aoid="SameValue" id="_ref_19"><a href="https://tc39.es/ecma262/#sec-samevalue">SameValue</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><li>Return <emu-const>unused</emu-const>.</li></ol></li></ol></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>value</var> » }.</li><li>Append <var>group</var> as the last element of <var>groups</var>.</li><li>Return <emu-const>unused</emu-const>.</li></ol></emu-alg>
   </emu-clause>
   </ins>
 </emu-clause><emu-annex id="sec-copyright-and-software-license">
diff --git a/spec.emu b/spec.emu
index c03feaf..9428b04 100644
--- a/spec.emu
+++ b/spec.emu
@@ -31,16 +31,13 @@ location: https://tc39.es/proposal-array-grouping/
     </emu-note>
     <p>When the `groupBy` method is called with two or three arguments, the following steps are taken:</p>
     <emu-alg>
-      1. Let _obj_ be OrdinaryObjectCreate(*null*).
       1. Let _groups_ be ? GroupBy(_items_, _callbackfn_, ~property~).
+      1. Let _obj_ be OrdinaryObjectCreate(*null*).
       1. For each Record { [[Key]], [[Elements]] } _g_ of _groups_, do
         1. Let _elements_ be CreateArrayFromList(_g_.[[Elements]]).
         1. Perform ? CreateDataPropertyOrThrow(_obj_, _g_.[[Key]], _elements_).
       1. Return _obj_.
     </emu-alg>
-    <emu-note>
-      <p>This method is an intentionally generic factory method; it does not require that its this value be the Object constructor. Therefore it can be transferred to or inherited by any other constructors that have no arguments.</p>
-    </emu-note>
   </emu-clause>
   </ins>
 </emu-clause>
@@ -58,20 +55,14 @@ location: https://tc39.es/proposal-array-grouping/
     </emu-note>
     <p>When the `groupBy` method is called with two or three arguments, the following steps are taken:</p>
     <emu-alg>
-      1. Let _C_ be the *this* value.
-      1. If IsConstructor(_C_) is *false*, throw a *TypeError* exception.
-      1. Let _map_ be ? Construct(_C_).
-      1. Let _adder_ be ? Get(_map_, *"set"*).
-      1. If IsCallable(_adder_) is *false*, throw a *TypeError* exception.
-      1. Let _groups_ be ? GroupBy(_items_, _callbackfn_, ~none~).
+      1. Let _groups_ be ? GroupBy(_items_, _callbackfn_, ~zero~).
+      1. Let _map_ be ! Construct(%Map%).
       1. For each Record { [[Key]], [[Elements]] } _g_ of _groups_, do
         1. Let _elements_ be CreateArrayFromList(_g_.[[Elements]]).
-        1. Perform ? Call(_adder_, _map_, &laquo; _g_.[[Key]], _elements_ &raquo;).
+        1. Let _entry_ be the Record { [[Key]]: _g_.[[Key]], [[Value]]: _elements_ }.
+        1. Append _entry_ as the last element of _map_.[[MapData]].
       1. Return _map_.
     </emu-alg>
-    <emu-note>
-      <p>This method is an intentionally generic factory method; it does not require that its this value be the Map constructor. Therefore it can be transferred to or inherited by any other constructors that have no arguments.</p>
-    </emu-note>
   </emu-clause>
   </ins>
 </emu-clause>
@@ -85,12 +76,13 @@ location: https://tc39.es/proposal-array-grouping/
       GroupBy (
         _items_: an ECMAScript language value,
         _callbackfn_: an ECMAScript language value,
-        _coercion_: ~none~ or ~property~,
+        _coercion_: ~property~ or ~zero~,
       ): either a normal completion containing a List of Records with fields [[Key]] (an ECMAScript language value) and [[Elements]] (a List of ECMAScript language values), or a throw completion
     </h1>
     <dl class="header">
     </dl>
     <emu-alg>
+      1. Perform ? RequireObjectCoercible(_items_).
       1. If IsCallable(_callbackfn_) is *false*, throw a *TypeError* exception.
       1. Let _groups_ be a new empty List.
       1. Let _iteratorRecord_ be ? GetIterator(_items_).
@@ -109,6 +101,9 @@ location: https://tc39.es/proposal-array-grouping/
         1. If _coercion_ is ~property~, then
           1. Set _key_ to Completion(ToPropertyKey(_key_)).
           1. IfAbruptCloseIterator(_key_, _iteratorRecord_).
+        1. Else,
+          1. Assert: _coercion_ is ~zero~.
+          1. If _key_ is *-0*<sub>𝔽</sub>, set _key_ to *+0*<sub>𝔽</sub>.
         1. Perform AddValueToKeyedGroup(_groups_, _key_, _value_).
         1. Set _k_ to _k_ + 1.
     </emu-alg>