Explicitly implementing some DOM iterable APIs for performance

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index e2aff07cf3b8380f17f4db566a4f0ec50eda51ce..4a91c619ac249432eca5656fc71cf6926aae4f6a 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -7246,7 +7246,11 @@ class DomStringList extends NativeFieldWrapperClass1 with ListMixin<String>, Imm
   @DocsEditable
   int get length native "DOMStringList_length_Getter";
 
-  String operator[](int index) native "DOMStringList_item_Callback";
+  String operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);

[sra1, 2013/05/09 19:55:50]

Do you know if the native indexer does a bounds check?
I would expect it does.

[blois, 2013/05/09 20:00:25]

It does not throw an exception for out of bounds (the test I added to node_test
was failing without this).

+    return _nativeIndexedGetter(index);
+  }
+  String _nativeIndexedGetter(int index) native "DOMStringList_item_Callback";
 
   void operator[]=(int index, String value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -7259,6 +7263,34 @@ class DomStringList extends NativeFieldWrapperClass1 with ListMixin<String>, Imm
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  String get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  String get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  String get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  String elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<String> mixins.
 
   @DomName('DOMStringList.contains')
@@ -9533,7 +9565,11 @@ class FileList extends NativeFieldWrapperClass1 with ListMixin<File>, ImmutableL
   @DocsEditable
   int get length native "FileList_length_Getter";
 
-  File operator[](int index) native "FileList_item_Callback";
+  File operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  File _nativeIndexedGetter(int index) native "FileList_item_Callback";
 
   void operator[]=(int index, File value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -9546,6 +9582,34 @@ class FileList extends NativeFieldWrapperClass1 with ListMixin<File>, ImmutableL
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  File get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  File get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  File get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  File elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<File> mixins.
 
   @DomName('FileList.item')
@@ -10379,7 +10443,11 @@ class HtmlAllCollection extends NativeFieldWrapperClass1 with ListMixin<Node>, I
   @DocsEditable
   int get length native "HTMLAllCollection_length_Getter";
 
-  Node operator[](int index) native "HTMLAllCollection_item_Callback";
+  Node operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Node _nativeIndexedGetter(int index) native "HTMLAllCollection_item_Callback";
 
   void operator[]=(int index, Node value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -10392,6 +10460,34 @@ class HtmlAllCollection extends NativeFieldWrapperClass1 with ListMixin<Node>, I
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Node get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Node elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Node> mixins.
 
   @DomName('HTMLAllCollection.item')
@@ -10423,7 +10519,11 @@ class HtmlCollection extends NativeFieldWrapperClass1 with ListMixin<Node>, Immu
   @DocsEditable
   int get length native "HTMLCollection_length_Getter";
 
-  Node operator[](int index) native "HTMLCollection_item_Callback";
+  Node operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Node _nativeIndexedGetter(int index) native "HTMLCollection_item_Callback";
 
   void operator[]=(int index, Node value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -10436,6 +10536,34 @@ class HtmlCollection extends NativeFieldWrapperClass1 with ListMixin<Node>, Immu
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Node get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Node elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Node> mixins.
 
   @DomName('HTMLCollection.item')
@@ -14500,7 +14628,11 @@ class MimeTypeArray extends NativeFieldWrapperClass1 with ListMixin<MimeType>, I
   @DocsEditable
   int get length native "DOMMimeTypeArray_length_Getter";
 
-  MimeType operator[](int index) native "DOMMimeTypeArray_item_Callback";
+  MimeType operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  MimeType _nativeIndexedGetter(int index) native "DOMMimeTypeArray_item_Callback";
 
   void operator[]=(int index, MimeType value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -14513,6 +14645,34 @@ class MimeTypeArray extends NativeFieldWrapperClass1 with ListMixin<MimeType>, I
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  MimeType get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  MimeType get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  MimeType get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  MimeType elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<MimeType> mixins.
 
   @DomName('DOMMimeTypeArray.item')
@@ -15717,7 +15877,11 @@ class NodeList extends NativeFieldWrapperClass1 with ListMixin<Node>, ImmutableL
   @DocsEditable
   int get length native "NodeList_length_Getter";
 
-  Node operator[](int index) native "NodeList_item_Callback";
+  Node operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Node _nativeIndexedGetter(int index) native "NodeList_item_Callback";
 
   void operator[]=(int index, Node value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -15730,6 +15894,34 @@ class NodeList extends NativeFieldWrapperClass1 with ListMixin<Node>, ImmutableL
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Node get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Node elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Node> mixins.
 
   @DomName('NodeList.item')
@@ -16854,7 +17046,11 @@ class PluginArray extends NativeFieldWrapperClass1 with ListMixin<Plugin>, Immut
   @DocsEditable
   int get length native "DOMPluginArray_length_Getter";
 
-  Plugin operator[](int index) native "DOMPluginArray_item_Callback";
+  Plugin operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Plugin _nativeIndexedGetter(int index) native "DOMPluginArray_item_Callback";
 
   void operator[]=(int index, Plugin value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -16867,6 +17063,34 @@ class PluginArray extends NativeFieldWrapperClass1 with ListMixin<Plugin>, Immut
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Plugin get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Plugin get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Plugin get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Plugin elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Plugin> mixins.
 
   @DomName('DOMPluginArray.item')
@@ -18644,7 +18868,11 @@ class SourceBufferList extends EventTarget with ListMixin<SourceBuffer>, Immutab
   @DocsEditable
   int get length native "SourceBufferList_length_Getter";
 
-  SourceBuffer operator[](int index) native "SourceBufferList_item_Callback";
+  SourceBuffer operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  SourceBuffer _nativeIndexedGetter(int index) native "SourceBufferList_item_Callback";
 
   void operator[]=(int index, SourceBuffer value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -18657,6 +18885,34 @@ class SourceBufferList extends EventTarget with ListMixin<SourceBuffer>, Immutab
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  SourceBuffer get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  SourceBuffer get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  SourceBuffer get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  SourceBuffer elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<SourceBuffer> mixins.
 
   @DomName('SourceBufferList.addEventListener')
@@ -18797,7 +19053,11 @@ class SpeechGrammarList extends NativeFieldWrapperClass1 with ListMixin<SpeechGr
   @DocsEditable
   int get length native "SpeechGrammarList_length_Getter";
 
-  SpeechGrammar operator[](int index) native "SpeechGrammarList_item_Callback";
+  SpeechGrammar operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  SpeechGrammar _nativeIndexedGetter(int index) native "SpeechGrammarList_item_Callback";
 
   void operator[]=(int index, SpeechGrammar value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -18810,6 +19070,34 @@ class SpeechGrammarList extends NativeFieldWrapperClass1 with ListMixin<SpeechGr
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  SpeechGrammar get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  SpeechGrammar get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  SpeechGrammar get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  SpeechGrammar elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<SpeechGrammar> mixins.
 
   void addFromString(String string, [num weight]) {
@@ -20362,7 +20650,11 @@ class TextTrackCueList extends NativeFieldWrapperClass1 with ListMixin<TextTrack
   @DocsEditable
   int get length native "TextTrackCueList_length_Getter";
 
-  TextTrackCue operator[](int index) native "TextTrackCueList_item_Callback";
+  TextTrackCue operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  TextTrackCue _nativeIndexedGetter(int index) native "TextTrackCueList_item_Callback";
 
   void operator[]=(int index, TextTrackCue value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -20375,6 +20667,34 @@ class TextTrackCueList extends NativeFieldWrapperClass1 with ListMixin<TextTrack
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  TextTrackCue get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  TextTrackCue get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  TextTrackCue get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  TextTrackCue elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<TextTrackCue> mixins.
 
   @DomName('TextTrackCueList.getCueById')
@@ -20406,7 +20726,11 @@ class TextTrackList extends EventTarget with ListMixin<TextTrack>, ImmutableList
   @DocsEditable
   int get length native "TextTrackList_length_Getter";
 
-  TextTrack operator[](int index) native "TextTrackList_item_Callback";
+  TextTrack operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  TextTrack _nativeIndexedGetter(int index) native "TextTrackList_item_Callback";
 
   void operator[]=(int index, TextTrack value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -20419,6 +20743,34 @@ class TextTrackList extends EventTarget with ListMixin<TextTrack>, ImmutableList
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  TextTrack get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  TextTrack get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  TextTrack get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  TextTrack elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<TextTrack> mixins.
 
   @DomName('TextTrackList.addEventListener')
@@ -20667,7 +21019,11 @@ class TouchList extends NativeFieldWrapperClass1 with ListMixin<Touch>, Immutabl
   @DocsEditable
   int get length native "TouchList_length_Getter";
 
-  Touch operator[](int index) native "TouchList_item_Callback";
+  Touch operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Touch _nativeIndexedGetter(int index) native "TouchList_item_Callback";
 
   void operator[]=(int index, Touch value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -20680,6 +21036,34 @@ class TouchList extends NativeFieldWrapperClass1 with ListMixin<Touch>, Immutabl
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Touch get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Touch get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Touch get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Touch elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Touch> mixins.
 
   @DomName('TouchList.item')
@@ -22796,7 +23180,11 @@ class _ClientRectList extends NativeFieldWrapperClass1 with ListMixin<Rect>, Imm
   @DocsEditable
   int get length native "ClientRectList_length_Getter";
 
-  Rect operator[](int index) native "ClientRectList_item_Callback";
+  Rect operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Rect _nativeIndexedGetter(int index) native "ClientRectList_item_Callback";
 
   void operator[]=(int index, Rect value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -22809,6 +23197,34 @@ class _ClientRectList extends NativeFieldWrapperClass1 with ListMixin<Rect>, Imm
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Rect get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Rect get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Rect get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Rect elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Rect> mixins.
 
   @DomName('ClientRectList.item')
@@ -22845,7 +23261,11 @@ class _CssRuleList extends NativeFieldWrapperClass1 with ListMixin<CssRule>, Imm
   @DocsEditable
   int get length native "CSSRuleList_length_Getter";
 
-  CssRule operator[](int index) native "CSSRuleList_item_Callback";
+  CssRule operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  CssRule _nativeIndexedGetter(int index) native "CSSRuleList_item_Callback";
 
   void operator[]=(int index, CssRule value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -22858,6 +23278,34 @@ class _CssRuleList extends NativeFieldWrapperClass1 with ListMixin<CssRule>, Imm
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  CssRule get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  CssRule get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  CssRule get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  CssRule elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<CssRule> mixins.
 
   @DomName('CSSRuleList.item')
@@ -22881,7 +23329,11 @@ class _CssValueList extends _CSSValue with ListMixin<_CSSValue>, ImmutableListMi
   @DocsEditable
   int get length native "CSSValueList_length_Getter";
 
-  _CSSValue operator[](int index) native "CSSValueList_item_Callback";
+  _CSSValue operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  _CSSValue _nativeIndexedGetter(int index) native "CSSValueList_item_Callback";
 
   void operator[]=(int index, _CSSValue value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -22894,6 +23346,34 @@ class _CssValueList extends _CSSValue with ListMixin<_CSSValue>, ImmutableListMi
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  _CSSValue get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  _CSSValue get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  _CSSValue get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  _CSSValue elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<_CSSValue> mixins.
 
   @DomName('CSSValueList.item')
@@ -23185,7 +23665,11 @@ class _EntryArray extends NativeFieldWrapperClass1 with ListMixin<Entry>, Immuta
   @DocsEditable
   int get length native "EntryArray_length_Getter";
 
-  Entry operator[](int index) native "EntryArray_item_Callback";
+  Entry operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Entry _nativeIndexedGetter(int index) native "EntryArray_item_Callback";
 
   void operator[]=(int index, Entry value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -23198,6 +23682,34 @@ class _EntryArray extends NativeFieldWrapperClass1 with ListMixin<Entry>, Immuta
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Entry get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Entry get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Entry get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Entry elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Entry> mixins.
 
   @DomName('EntryArray.item')
@@ -23221,7 +23733,11 @@ class _EntryArraySync extends NativeFieldWrapperClass1 with ListMixin<_EntrySync
   @DocsEditable
   int get length native "EntryArraySync_length_Getter";
 
-  _EntrySync operator[](int index) native "EntryArraySync_item_Callback";
+  _EntrySync operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  _EntrySync _nativeIndexedGetter(int index) native "EntryArraySync_item_Callback";
 
   void operator[]=(int index, _EntrySync value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -23234,6 +23750,34 @@ class _EntryArraySync extends NativeFieldWrapperClass1 with ListMixin<_EntrySync
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  _EntrySync get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  _EntrySync get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  _EntrySync get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  _EntrySync elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<_EntrySync> mixins.
 
   @DomName('EntryArraySync.item')
@@ -23318,7 +23862,11 @@ class _GamepadList extends NativeFieldWrapperClass1 with ListMixin<Gamepad>, Imm
   @DocsEditable
   int get length native "GamepadList_length_Getter";
 
-  Gamepad operator[](int index) native "GamepadList_item_Callback";
+  Gamepad operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Gamepad _nativeIndexedGetter(int index) native "GamepadList_item_Callback";
 
   void operator[]=(int index, Gamepad value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -23331,6 +23879,34 @@ class _GamepadList extends NativeFieldWrapperClass1 with ListMixin<Gamepad>, Imm
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Gamepad get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Gamepad get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Gamepad get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Gamepad elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Gamepad> mixins.
 
   @DomName('GamepadList.item')
@@ -23445,7 +24021,11 @@ class _NamedNodeMap extends NativeFieldWrapperClass1 with ListMixin<Node>, Immut
   @DocsEditable
   int get length native "NamedNodeMap_length_Getter";
 
-  Node operator[](int index) native "NamedNodeMap_item_Callback";
+  Node operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  Node _nativeIndexedGetter(int index) native "NamedNodeMap_item_Callback";
 
   void operator[]=(int index, Node value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -23458,6 +24038,34 @@ class _NamedNodeMap extends NativeFieldWrapperClass1 with ListMixin<Node>, Immut
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Node get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  Node get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Node elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<Node> mixins.
 
   @DomName('NamedNodeMap.getNamedItem')
@@ -23589,7 +24197,11 @@ class _SpeechInputResultList extends NativeFieldWrapperClass1 with ListMixin<Spe
   @DocsEditable
   int get length native "SpeechInputResultList_length_Getter";
 
-  SpeechInputResult operator[](int index) native "SpeechInputResultList_item_Callback";
+  SpeechInputResult operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  SpeechInputResult _nativeIndexedGetter(int index) native "SpeechInputResultList_item_Callback";
 
   void operator[]=(int index, SpeechInputResult value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -23602,6 +24214,34 @@ class _SpeechInputResultList extends NativeFieldWrapperClass1 with ListMixin<Spe
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  SpeechInputResult get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  SpeechInputResult get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  SpeechInputResult get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  SpeechInputResult elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<SpeechInputResult> mixins.
 
   @DomName('SpeechInputResultList.item')
@@ -23625,7 +24265,11 @@ class _SpeechRecognitionResultList extends NativeFieldWrapperClass1 with ListMix
   @DocsEditable
   int get length native "SpeechRecognitionResultList_length_Getter";
 
-  SpeechRecognitionResult operator[](int index) native "SpeechRecognitionResultList_item_Callback";
+  SpeechRecognitionResult operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  SpeechRecognitionResult _nativeIndexedGetter(int index) native "SpeechRecognitionResultList_item_Callback";
 
   void operator[]=(int index, SpeechRecognitionResult value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -23638,6 +24282,34 @@ class _SpeechRecognitionResultList extends NativeFieldWrapperClass1 with ListMix
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  SpeechRecognitionResult get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  SpeechRecognitionResult get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  SpeechRecognitionResult get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  SpeechRecognitionResult elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<SpeechRecognitionResult> mixins.
 
   @DomName('SpeechRecognitionResultList.item')
@@ -23661,7 +24333,11 @@ class _StyleSheetList extends NativeFieldWrapperClass1 with ListMixin<StyleSheet
   @DocsEditable
   int get length native "StyleSheetList_length_Getter";
 
-  StyleSheet operator[](int index) native "StyleSheetList_item_Callback";
+  StyleSheet operator[](int index) {
+    if (index < 0 || index >= length) throw new RangeError.range(index, 0, length);
+    return _nativeIndexedGetter(index);
+  }
+  StyleSheet _nativeIndexedGetter(int index) native "StyleSheetList_item_Callback";
 
   void operator[]=(int index, StyleSheet value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -23674,6 +24350,34 @@ class _StyleSheetList extends NativeFieldWrapperClass1 with ListMixin<StyleSheet
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  StyleSheet get first {
+    if (this.length > 0) {
+      return this[0];
+    }
+    throw new StateError("No elements");
+  }
+
+  StyleSheet get last {
+    int len = this.length;
+    if (len > 0) {
+      return this[len - 1];
+    }
+    throw new StateError("No elements");
+  }
+
+  StyleSheet get single {
+    int len = this.length;
+    if (len == 1) {
+      return this[0];
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  StyleSheet elementAt(int index) {
+    return this[index];
+  }
+
   // -- end List<StyleSheet> mixins.
 
   @DomName('StyleSheetList.item')