diff --git a/CHANGELOG.md b/CHANGELOG.md
index 508c7662..1058222c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,8 @@
 ## 0.3.1-dev
 
 - Updated types to account for union types.
+- Fixed issue where all `JSAny`s were treated as nullable.
+- Changed `JSVoid` to `void`.
 
 ## 0.3.0
 
diff --git a/lib/src/dom/anchors.dart b/lib/src/dom/anchors.dart
index 40504239..eadc6742 100644
--- a/lib/src/dom/anchors.dart
+++ b/lib/src/dom/anchors.dart
@@ -12,7 +12,7 @@ class XRAnchor implements JSObject {}
 
 extension XRAnchorExtension on XRAnchor {
   external JSPromise requestPersistentHandle();
-  external JSVoid delete();
+  external void delete();
   external XRSpace get anchorSpace;
 }
 
diff --git a/lib/src/dom/angle_instanced_arrays.dart b/lib/src/dom/angle_instanced_arrays.dart
index 2eea1eaa..3c5cd548 100644
--- a/lib/src/dom/angle_instanced_arrays.dart
+++ b/lib/src/dom/angle_instanced_arrays.dart
@@ -13,20 +13,20 @@ class ANGLE_instanced_arrays implements JSObject {
 }
 
 extension ANGLEInstancedArraysExtension on ANGLE_instanced_arrays {
-  external JSVoid drawArraysInstancedANGLE(
+  external void drawArraysInstancedANGLE(
     GLenum mode,
     GLint first,
     GLsizei count,
     GLsizei primcount,
   );
-  external JSVoid drawElementsInstancedANGLE(
+  external void drawElementsInstancedANGLE(
     GLenum mode,
     GLsizei count,
     GLenum type,
     GLintptr offset,
     GLsizei primcount,
   );
-  external JSVoid vertexAttribDivisorANGLE(
+  external void vertexAttribDivisorANGLE(
     GLuint index,
     GLuint divisor,
   );
diff --git a/lib/src/dom/background_fetch.dart b/lib/src/dom/background_fetch.dart
index 06e6312f..b5c7d409 100644
--- a/lib/src/dom/background_fetch.dart
+++ b/lib/src/dom/background_fetch.dart
@@ -19,7 +19,7 @@ class BackgroundFetchManager implements JSObject {}
 extension BackgroundFetchManagerExtension on BackgroundFetchManager {
   external JSPromise fetch(
     String id,
-    JSAny? requests, [
+    JSAny requests, [
     BackgroundFetchOptions options,
   ]);
   external JSPromise get(String id);
diff --git a/lib/src/dom/clipboard_apis.dart b/lib/src/dom/clipboard_apis.dart
index 4aa55595..56aa76e4 100644
--- a/lib/src/dom/clipboard_apis.dart
+++ b/lib/src/dom/clipboard_apis.dart
@@ -41,7 +41,7 @@ extension ClipboardEventExtension on ClipboardEvent {
 @staticInterop
 class ClipboardItem implements JSObject {
   external factory ClipboardItem(
-    JSAny? items, [
+    JSAny items, [
     ClipboardItemOptions options,
   ]);
 
diff --git a/lib/src/dom/compute_pressure.dart b/lib/src/dom/compute_pressure.dart
index 7f480d14..3e8b288c 100644
--- a/lib/src/dom/compute_pressure.dart
+++ b/lib/src/dom/compute_pressure.dart
@@ -23,8 +23,8 @@ class PressureObserver implements JSObject {
 
 extension PressureObserverExtension on PressureObserver {
   external JSPromise observe(PressureSource source);
-  external JSVoid unobserve(PressureSource source);
-  external JSVoid disconnect();
+  external void unobserve(PressureSource source);
+  external void disconnect();
   external JSArray takeRecords();
 }
 
diff --git a/lib/src/dom/console.dart b/lib/src/dom/console.dart
index 67a3b90e..faf75593 100644
--- a/lib/src/dom/console.dart
+++ b/lib/src/dom/console.dart
@@ -13,35 +13,35 @@ abstract class $Console {}
 
 extension $ConsoleExtension on $Console {
   @JS('assert')
-  external JSVoid assert_(
+  external void assert_(
     JSAny? data, [
     bool condition,
   ]);
-  external JSVoid clear();
-  external JSVoid debug(JSAny? data);
-  external JSVoid error(JSAny? data);
-  external JSVoid info(JSAny? data);
-  external JSVoid log(JSAny? data);
-  external JSVoid table([
+  external void clear();
+  external void debug(JSAny? data);
+  external void error(JSAny? data);
+  external void info(JSAny? data);
+  external void log(JSAny? data);
+  external void table([
     JSAny? tabularData,
     JSArray properties,
   ]);
-  external JSVoid trace(JSAny? data);
-  external JSVoid warn(JSAny? data);
-  external JSVoid dir([
+  external void trace(JSAny? data);
+  external void warn(JSAny? data);
+  external void dir([
     JSAny? item,
     JSObject? options,
   ]);
-  external JSVoid dirxml(JSAny? data);
-  external JSVoid count([String label]);
-  external JSVoid countReset([String label]);
-  external JSVoid group(JSAny? data);
-  external JSVoid groupCollapsed(JSAny? data);
-  external JSVoid groupEnd();
-  external JSVoid time([String label]);
-  external JSVoid timeLog(
+  external void dirxml(JSAny? data);
+  external void count([String label]);
+  external void countReset([String label]);
+  external void group(JSAny? data);
+  external void groupCollapsed(JSAny? data);
+  external void groupEnd();
+  external void time([String label]);
+  external void timeLog(
     JSAny? data, [
     String label,
   ]);
-  external JSVoid timeEnd([String label]);
+  external void timeEnd([String label]);
 }
diff --git a/lib/src/dom/cookie_store.dart b/lib/src/dom/cookie_store.dart
index 2415fecb..22cb29c9 100644
--- a/lib/src/dom/cookie_store.dart
+++ b/lib/src/dom/cookie_store.dart
@@ -17,13 +17,13 @@ typedef CookieSameSite = String;
 class CookieStore implements EventTarget {}
 
 extension CookieStoreExtension on CookieStore {
-  external JSPromise get([JSAny? nameOrOptions]);
-  external JSPromise getAll([JSAny? nameOrOptions]);
+  external JSPromise get([JSAny nameOrOptions]);
+  external JSPromise getAll([JSAny nameOrOptions]);
   external JSPromise set(
-    JSAny? nameOrOptions, [
+    JSAny nameOrOptions, [
     String value,
   ]);
-  external JSPromise delete(JSAny? nameOrOptions);
+  external JSPromise delete(JSAny nameOrOptions);
   external set onchange(EventHandler value);
   external EventHandler get onchange;
 }
diff --git a/lib/src/dom/css_animation_worklet.dart b/lib/src/dom/css_animation_worklet.dart
index ec04e2a0..a4b2a368 100644
--- a/lib/src/dom/css_animation_worklet.dart
+++ b/lib/src/dom/css_animation_worklet.dart
@@ -14,7 +14,7 @@ typedef AnimatorInstanceConstructor = JSFunction;
 class AnimationWorkletGlobalScope implements WorkletGlobalScope {}
 
 extension AnimationWorkletGlobalScopeExtension on AnimationWorkletGlobalScope {
-  external JSVoid registerAnimator(
+  external void registerAnimator(
     String name,
     AnimatorInstanceConstructor animatorCtor,
   );
diff --git a/lib/src/dom/css_animations.dart b/lib/src/dom/css_animations.dart
index fffe0186..6f3bbb4e 100644
--- a/lib/src/dom/css_animations.dart
+++ b/lib/src/dom/css_animations.dart
@@ -57,8 +57,8 @@ extension CSSKeyframeRuleExtension on CSSKeyframeRule {
 class CSSKeyframesRule implements CSSRule {}
 
 extension CSSKeyframesRuleExtension on CSSKeyframesRule {
-  external JSVoid appendRule(String rule);
-  external JSVoid deleteRule(String select);
+  external void appendRule(String rule);
+  external void deleteRule(String select);
   external CSSKeyframeRule? findRule(String select);
   external set name(String value);
   external String get name;
diff --git a/lib/src/dom/css_font_loading.dart b/lib/src/dom/css_font_loading.dart
index fd206a71..58f4c7b5 100644
--- a/lib/src/dom/css_font_loading.dart
+++ b/lib/src/dom/css_font_loading.dart
@@ -57,7 +57,7 @@ extension FontFaceDescriptorsExtension on FontFaceDescriptors {
 class FontFace implements JSObject {
   external factory FontFace(
     String family,
-    JSAny? source, [
+    JSAny source, [
     FontFaceDescriptors descriptors,
   ]);
 }
@@ -167,7 +167,7 @@ class FontFaceSet implements EventTarget {
 extension FontFaceSetExtension on FontFaceSet {
   external FontFaceSet add(FontFace font);
   external bool delete(FontFace font);
-  external JSVoid clear();
+  external void clear();
   external JSPromise load(
     String font, [
     String text,
diff --git a/lib/src/dom/css_fonts.dart b/lib/src/dom/css_fonts.dart
index 5ca78922..f0e66055 100644
--- a/lib/src/dom/css_fonts.dart
+++ b/lib/src/dom/css_fonts.dart
@@ -34,9 +34,9 @@ extension CSSFontFeatureValuesRuleExtension on CSSFontFeatureValuesRule {
 class CSSFontFeatureValuesMap implements JSObject {}
 
 extension CSSFontFeatureValuesMapExtension on CSSFontFeatureValuesMap {
-  external JSVoid set(
+  external void set(
     String featureValueName,
-    JSAny? values,
+    JSAny values,
   );
 }
 
diff --git a/lib/src/dom/css_layout_api.dart b/lib/src/dom/css_layout_api.dart
index ff3a3b1f..74634e1e 100644
--- a/lib/src/dom/css_layout_api.dart
+++ b/lib/src/dom/css_layout_api.dart
@@ -18,7 +18,7 @@ typedef BreakType = String;
 class LayoutWorkletGlobalScope implements WorkletGlobalScope {}
 
 extension LayoutWorkletGlobalScopeExtension on LayoutWorkletGlobalScope {
-  external JSVoid registerLayout(
+  external void registerLayout(
     String name,
     VoidFunction layoutCtor,
   );
diff --git a/lib/src/dom/css_paint_api.dart b/lib/src/dom/css_paint_api.dart
index cffc90c4..2964e5e5 100644
--- a/lib/src/dom/css_paint_api.dart
+++ b/lib/src/dom/css_paint_api.dart
@@ -12,7 +12,7 @@ import 'webidl.dart';
 class PaintWorkletGlobalScope implements WorkletGlobalScope {}
 
 extension PaintWorkletGlobalScopeExtension on PaintWorkletGlobalScope {
-  external JSVoid registerPaint(
+  external void registerPaint(
     String name,
     VoidFunction paintCtor,
   );
diff --git a/lib/src/dom/css_parser_api.dart b/lib/src/dom/css_parser_api.dart
index f31ec11a..ee1c423e 100644
--- a/lib/src/dom/css_parser_api.dart
+++ b/lib/src/dom/css_parser_api.dart
@@ -4,8 +4,8 @@
 
 import 'dart:js_interop';
 
-typedef CSSStringSource = JSAny?;
-typedef CSSToken = JSAny?;
+typedef CSSStringSource = JSAny;
+typedef CSSToken = JSAny;
 
 @JS()
 @staticInterop
diff --git a/lib/src/dom/css_typed_om.dart b/lib/src/dom/css_typed_om.dart
index 765c8f40..dcbf3903 100644
--- a/lib/src/dom/css_typed_om.dart
+++ b/lib/src/dom/css_typed_om.dart
@@ -6,14 +6,14 @@ import 'dart:js_interop';
 
 import 'geometry.dart';
 
-typedef CSSUnparsedSegment = JSAny?;
-typedef CSSKeywordish = JSAny?;
-typedef CSSNumberish = JSAny?;
-typedef CSSPerspectiveValue = JSAny?;
-typedef CSSColorRGBComp = JSAny?;
-typedef CSSColorPercent = JSAny?;
-typedef CSSColorNumber = JSAny?;
-typedef CSSColorAngle = JSAny?;
+typedef CSSUnparsedSegment = JSAny;
+typedef CSSKeywordish = JSAny;
+typedef CSSNumberish = JSAny;
+typedef CSSPerspectiveValue = JSAny;
+typedef CSSColorRGBComp = JSAny;
+typedef CSSColorPercent = JSAny;
+typedef CSSColorNumber = JSAny;
+typedef CSSColorAngle = JSAny;
 typedef CSSNumericBaseType = String;
 typedef CSSMathOperator = String;
 
@@ -46,16 +46,16 @@ extension StylePropertyMapReadOnlyExtension on StylePropertyMapReadOnly {
 class StylePropertyMap implements StylePropertyMapReadOnly {}
 
 extension StylePropertyMapExtension on StylePropertyMap {
-  external JSVoid set(
+  external void set(
     String property,
-    JSAny? values,
+    JSAny values,
   );
-  external JSVoid append(
+  external void append(
     String property,
-    JSAny? values,
+    JSAny values,
   );
-  external JSVoid delete(String property);
-  external JSVoid clear();
+  external void delete(String property);
+  external void clear();
 }
 
 @JS('CSSUnparsedValue')
@@ -300,7 +300,7 @@ extension CSSTranslateExtension on CSSTranslate {
 @staticInterop
 class CSSRotate implements CSSTransformComponent {
   external factory CSSRotate(
-    JSAny? angleOrX, [
+    JSAny angleOrX, [
     CSSNumberish y,
     CSSNumberish z,
     CSSNumericValue angle,
diff --git a/lib/src/dom/css_view_transitions.dart b/lib/src/dom/css_view_transitions.dart
index 2ba42c61..8b6f759c 100644
--- a/lib/src/dom/css_view_transitions.dart
+++ b/lib/src/dom/css_view_transitions.dart
@@ -11,7 +11,7 @@ typedef UpdateCallback = JSFunction;
 class ViewTransition implements JSObject {}
 
 extension ViewTransitionExtension on ViewTransition {
-  external JSVoid skipTransition();
+  external void skipTransition();
   external JSPromise get updateCallbackDone;
   external JSPromise get ready;
   external JSPromise get finished;
diff --git a/lib/src/dom/cssom.dart b/lib/src/dom/cssom.dart
index 8e63db2d..b61e2c9a 100644
--- a/lib/src/dom/cssom.dart
+++ b/lib/src/dom/cssom.dart
@@ -16,8 +16,8 @@ class MediaList implements JSObject {}
 
 extension MediaListExtension on MediaList {
   external String? item(int index);
-  external JSVoid appendMedium(String medium);
-  external JSVoid deleteMedium(String medium);
+  external void appendMedium(String medium);
+  external void deleteMedium(String medium);
   external set mediaText(String value);
   external String get mediaText;
   external int get length;
@@ -49,15 +49,15 @@ extension CSSStyleSheetExtension on CSSStyleSheet {
     String rule, [
     int index,
   ]);
-  external JSVoid deleteRule(int index);
+  external void deleteRule(int index);
   external JSPromise replace(String text);
-  external JSVoid replaceSync(String text);
+  external void replaceSync(String text);
   external int addRule([
     String selector,
     String style,
     int index,
   ]);
-  external JSVoid removeRule([int index]);
+  external void removeRule([int index]);
   external CSSRule? get ownerRule;
   external CSSRuleList get cssRules;
   external CSSRuleList get rules;
@@ -69,7 +69,7 @@ extension CSSStyleSheetExtension on CSSStyleSheet {
 class CSSStyleSheetInit implements JSObject {
   external factory CSSStyleSheetInit({
     String baseURL,
-    JSAny? media,
+    JSAny media,
     bool disabled,
   });
 }
@@ -77,8 +77,8 @@ class CSSStyleSheetInit implements JSObject {
 extension CSSStyleSheetInitExtension on CSSStyleSheetInit {
   external set baseURL(String value);
   external String get baseURL;
-  external set media(JSAny? value);
-  external JSAny? get media;
+  external set media(JSAny value);
+  external JSAny get media;
   external set disabled(bool value);
   external bool get disabled;
 }
@@ -167,7 +167,7 @@ extension CSSGroupingRuleExtension on CSSGroupingRule {
     String rule, [
     int index,
   ]);
-  external JSVoid deleteRule(int index);
+  external void deleteRule(int index);
   external CSSRuleList get cssRules;
 }
 
@@ -207,7 +207,7 @@ extension CSSStyleDeclarationExtension on CSSStyleDeclaration {
   external String item(int index);
   external String getPropertyValue(String property);
   external String getPropertyPriority(String property);
-  external JSVoid setProperty(
+  external void setProperty(
     String property,
     String value, [
     String priority,
@@ -1521,7 +1521,7 @@ extension $CSSExtension on $CSS {
   external CSSToken parseValue(String css);
   external JSArray parseValueList(String css);
   external JSArray parseCommaValueList(String css);
-  external JSVoid registerProperty(PropertyDefinition definition);
+  external void registerProperty(PropertyDefinition definition);
   external CSSUnitValue number(num value);
   external CSSUnitValue percent(num value);
   external CSSUnitValue cap(num value);
diff --git a/lib/src/dom/cssom_view.dart b/lib/src/dom/cssom_view.dart
index ad6dc375..70d7425b 100644
--- a/lib/src/dom/cssom_view.dart
+++ b/lib/src/dom/cssom_view.dart
@@ -48,8 +48,8 @@ extension ScrollToOptionsExtension on ScrollToOptions {
 class MediaQueryList implements EventTarget {}
 
 extension MediaQueryListExtension on MediaQueryList {
-  external JSVoid addListener(EventListener? callback);
-  external JSVoid removeListener(EventListener? callback);
+  external void addListener(EventListener? callback);
+  external void removeListener(EventListener? callback);
   external String get media;
   external bool get matches;
   external set onchange(EventHandler value);
diff --git a/lib/src/dom/custom_state_pseudo_class.dart b/lib/src/dom/custom_state_pseudo_class.dart
index c55d3733..ef30f352 100644
--- a/lib/src/dom/custom_state_pseudo_class.dart
+++ b/lib/src/dom/custom_state_pseudo_class.dart
@@ -9,5 +9,5 @@ import 'dart:js_interop';
 class CustomStateSet implements JSObject {}
 
 extension CustomStateSetExtension on CustomStateSet {
-  external JSVoid add(String value);
+  external void add(String value);
 }
diff --git a/lib/src/dom/dom.dart b/lib/src/dom/dom.dart
index ebe2abf3..e9f33d69 100644
--- a/lib/src/dom/dom.dart
+++ b/lib/src/dom/dom.dart
@@ -49,10 +49,10 @@ class Event implements JSObject {
 
 extension EventExtension on Event {
   external JSArray composedPath();
-  external JSVoid stopPropagation();
-  external JSVoid stopImmediatePropagation();
-  external JSVoid preventDefault();
-  external JSVoid initEvent(
+  external void stopPropagation();
+  external void stopImmediatePropagation();
+  external void preventDefault();
+  external void initEvent(
     String type, [
     bool bubbles,
     bool cancelable,
@@ -104,7 +104,7 @@ class CustomEvent implements Event {
 }
 
 extension CustomEventExtension on CustomEvent {
-  external JSVoid initCustomEvent(
+  external void initCustomEvent(
     String type, [
     bool bubbles,
     bool cancelable,
@@ -132,15 +132,15 @@ class EventTarget implements JSObject {
 }
 
 extension EventTargetExtension on EventTarget {
-  external JSVoid addEventListener(
+  external void addEventListener(
     String type,
     EventListener? callback, [
-    JSAny? options,
+    JSAny options,
   ]);
-  external JSVoid removeEventListener(
+  external void removeEventListener(
     String type,
     EventListener? callback, [
-    JSAny? options,
+    JSAny options,
   ]);
   external bool dispatchEvent(Event event);
 }
@@ -184,7 +184,7 @@ class AbortController implements JSObject {
 }
 
 extension AbortControllerExtension on AbortController {
-  external JSVoid abort([JSAny? reason]);
+  external void abort([JSAny? reason]);
   external AbortSignal get signal;
 }
 
@@ -197,7 +197,7 @@ class AbortSignal implements EventTarget {
 }
 
 extension AbortSignalExtension on AbortSignal {
-  external JSVoid throwIfAborted();
+  external void throwIfAborted();
   external bool get aborted;
   external JSAny? get reason;
   external set onabort(EventHandler value);
@@ -232,9 +232,9 @@ extension DocumentOrShadowRootExtension on DocumentOrShadowRoot {
 class ParentNode implements JSObject {}
 
 extension ParentNodeExtension on ParentNode {
-  external JSVoid prepend(JSAny? nodes);
-  external JSVoid append(JSAny? nodes);
-  external JSVoid replaceChildren(JSAny? nodes);
+  external void prepend(JSAny nodes);
+  external void append(JSAny nodes);
+  external void replaceChildren(JSAny nodes);
   external Element? querySelector(String selectors);
   external NodeList querySelectorAll(String selectors);
   external HTMLCollection get children;
@@ -257,10 +257,10 @@ extension NonDocumentTypeChildNodeExtension on NonDocumentTypeChildNode {
 class ChildNode implements JSObject {}
 
 extension ChildNodeExtension on ChildNode {
-  external JSVoid before(JSAny? nodes);
-  external JSVoid after(JSAny? nodes);
-  external JSVoid replaceWith(JSAny? nodes);
-  external JSVoid remove();
+  external void before(JSAny nodes);
+  external void after(JSAny nodes);
+  external void replaceWith(JSAny nodes);
+  external void remove();
 }
 
 @JS('Slottable')
@@ -297,11 +297,11 @@ class MutationObserver implements JSObject {
 }
 
 extension MutationObserverExtension on MutationObserver {
-  external JSVoid observe(
+  external void observe(
     Node target, [
     MutationObserverInit options,
   ]);
-  external JSVoid disconnect();
+  external void disconnect();
   external JSArray takeRecords();
 }
 
@@ -379,7 +379,7 @@ class Node implements EventTarget {
 extension NodeExtension on Node {
   external Node getRootNode([GetRootNodeOptions options]);
   external bool hasChildNodes();
-  external JSVoid normalize();
+  external void normalize();
   external Node cloneNode([bool deep]);
   external bool isEqualNode(Node? otherNode);
   external bool isSameNode(Node? otherNode);
@@ -468,12 +468,12 @@ extension DocumentExtension on Document {
   external HTMLCollection getElementsByClassName(String classNames);
   external Element createElement(
     String localName, [
-    JSAny? options,
+    JSAny options,
   ]);
   external Element createElementNS(
     String? namespace,
     String qualifiedName, [
-    JSAny? options,
+    JSAny options,
   ]);
   external DocumentFragment createDocumentFragment();
   external Text createTextNode(String data);
@@ -517,9 +517,9 @@ extension DocumentExtension on Document {
     String nameOrUnused2,
     String features,
   ]);
-  external JSVoid close();
-  external JSVoid write(String text);
-  external JSVoid writeln(String text);
+  external void close();
+  external void write(String text);
+  external void writeln(String text);
   external bool hasFocus();
   external bool execCommand(
     String commandId, [
@@ -531,11 +531,11 @@ extension DocumentExtension on Document {
   external bool queryCommandState(String commandId);
   external bool queryCommandSupported(String commandId);
   external String queryCommandValue(String commandId);
-  external JSVoid clear();
-  external JSVoid captureEvents();
-  external JSVoid releaseEvents();
+  external void clear();
+  external void captureEvents();
+  external void releaseEvents();
   external JSPromise exitPictureInPicture();
-  external JSVoid exitPointerLock();
+  external void exitPointerLock();
   external JSPromise requestStorageAccessFor(String requestedOrigin);
   external Selection? getSelection();
   external JSPromise hasStorageAccess();
@@ -705,7 +705,7 @@ class Element
         Animatable {}
 
 extension ElementExtension on Element {
-  external JSVoid insertAdjacentHTML(
+  external void insertAdjacentHTML(
     String position,
     String text,
   );
@@ -720,17 +720,17 @@ extension ElementExtension on Element {
   external DOMRectList getClientRects();
   external DOMRect getBoundingClientRect();
   external bool checkVisibility([CheckVisibilityOptions options]);
-  external JSVoid scrollIntoView([JSAny? arg]);
-  external JSVoid scroll([
-    JSAny? optionsOrX,
+  external void scrollIntoView([JSAny arg]);
+  external void scroll([
+    JSAny optionsOrX,
     num y,
   ]);
-  external JSVoid scrollTo([
-    JSAny? optionsOrX,
+  external void scrollTo([
+    JSAny optionsOrX,
     num y,
   ]);
-  external JSVoid scrollBy([
-    JSAny? optionsOrX,
+  external void scrollBy([
+    JSAny optionsOrX,
     num y,
   ]);
   external bool hasAttributes();
@@ -740,17 +740,17 @@ extension ElementExtension on Element {
     String? namespace,
     String localName,
   );
-  external JSVoid setAttribute(
+  external void setAttribute(
     String qualifiedName,
     String value,
   );
-  external JSVoid setAttributeNS(
+  external void setAttributeNS(
     String? namespace,
     String qualifiedName,
     String value,
   );
-  external JSVoid removeAttribute(String qualifiedName);
-  external JSVoid removeAttributeNS(
+  external void removeAttribute(String qualifiedName);
+  external void removeAttributeNS(
     String? namespace,
     String localName,
   );
@@ -785,16 +785,16 @@ extension ElementExtension on Element {
     String where,
     Element element,
   );
-  external JSVoid insertAdjacentText(
+  external void insertAdjacentText(
     String where,
     String data,
   );
   external JSPromise requestFullscreen([FullscreenOptions options]);
-  external JSVoid setPointerCapture(int pointerId);
-  external JSVoid releasePointerCapture(int pointerId);
+  external void setPointerCapture(int pointerId);
+  external void releasePointerCapture(int pointerId);
   external bool hasPointerCapture(int pointerId);
-  external JSVoid requestPointerLock();
-  external JSVoid setHTML(
+  external void requestPointerLock();
+  external void setHTML(
     String input, [
     SetHTMLOptions options,
   ]);
@@ -897,16 +897,16 @@ extension CharacterDataExtension on CharacterData {
     int offset,
     int count,
   );
-  external JSVoid appendData(String data);
-  external JSVoid insertData(
+  external void appendData(String data);
+  external void insertData(
     int offset,
     String data,
   );
-  external JSVoid deleteData(
+  external void deleteData(
     int offset,
     int count,
   );
-  external JSVoid replaceData(
+  external void replaceData(
     int offset,
     int count,
     String data,
@@ -1001,32 +1001,32 @@ extension RangeExtension on Range {
   external DocumentFragment createContextualFragment(String fragment);
   external DOMRectList getClientRects();
   external DOMRect getBoundingClientRect();
-  external JSVoid setStart(
+  external void setStart(
     Node node,
     int offset,
   );
-  external JSVoid setEnd(
+  external void setEnd(
     Node node,
     int offset,
   );
-  external JSVoid setStartBefore(Node node);
-  external JSVoid setStartAfter(Node node);
-  external JSVoid setEndBefore(Node node);
-  external JSVoid setEndAfter(Node node);
-  external JSVoid collapse([bool toStart]);
-  external JSVoid selectNode(Node node);
-  external JSVoid selectNodeContents(Node node);
+  external void setStartBefore(Node node);
+  external void setStartAfter(Node node);
+  external void setEndBefore(Node node);
+  external void setEndAfter(Node node);
+  external void collapse([bool toStart]);
+  external void selectNode(Node node);
+  external void selectNodeContents(Node node);
   external int compareBoundaryPoints(
     int how,
     Range sourceRange,
   );
-  external JSVoid deleteContents();
+  external void deleteContents();
   external DocumentFragment extractContents();
   external DocumentFragment cloneContents();
-  external JSVoid insertNode(Node node);
-  external JSVoid surroundContents(Node newParent);
+  external void insertNode(Node node);
+  external void surroundContents(Node newParent);
   external Range cloneRange();
-  external JSVoid detach();
+  external void detach();
   external bool isPointInRange(
     Node node,
     int offset,
@@ -1046,7 +1046,7 @@ class NodeIterator implements JSObject {}
 extension NodeIteratorExtension on NodeIterator {
   external Node? nextNode();
   external Node? previousNode();
-  external JSVoid detach();
+  external void detach();
   external Node get root;
   external Node get referenceNode;
   external bool get pointerBeforeReferenceNode;
@@ -1080,8 +1080,8 @@ class DOMTokenList implements JSObject {}
 extension DOMTokenListExtension on DOMTokenList {
   external String? item(int index);
   external bool contains(String token);
-  external JSVoid add(String tokens);
-  external JSVoid remove(String tokens);
+  external void add(String tokens);
+  external void remove(String tokens);
   external bool toggle(
     String token, [
     bool force,
@@ -1167,13 +1167,13 @@ class XSLTProcessor implements JSObject {
 }
 
 extension XSLTProcessorExtension on XSLTProcessor {
-  external JSVoid importStylesheet(Node style);
+  external void importStylesheet(Node style);
   external DocumentFragment transformToFragment(
     Node source,
     Document output,
   );
   external Document transformToDocument(Node source);
-  external JSVoid setParameter(
+  external void setParameter(
     String namespaceURI,
     String localName,
     JSAny? value,
@@ -1182,10 +1182,10 @@ extension XSLTProcessorExtension on XSLTProcessor {
     String namespaceURI,
     String localName,
   );
-  external JSVoid removeParameter(
+  external void removeParameter(
     String namespaceURI,
     String localName,
   );
-  external JSVoid clearParameters();
-  external JSVoid reset();
+  external void clearParameters();
+  external void reset();
 }
diff --git a/lib/src/dom/edit_context.dart b/lib/src/dom/edit_context.dart
index 6959c793..70197b09 100644
--- a/lib/src/dom/edit_context.dart
+++ b/lib/src/dom/edit_context.dart
@@ -38,18 +38,18 @@ class EditContext implements EventTarget {
 }
 
 extension EditContextExtension on EditContext {
-  external JSVoid updateText(
+  external void updateText(
     int rangeStart,
     int rangeEnd,
     String text,
   );
-  external JSVoid updateSelection(
+  external void updateSelection(
     int start,
     int end,
   );
-  external JSVoid updateControlBounds(DOMRect controlBounds);
-  external JSVoid updateSelectionBounds(DOMRect selectionBounds);
-  external JSVoid updateCharacterBounds(
+  external void updateControlBounds(DOMRect controlBounds);
+  external void updateSelectionBounds(DOMRect selectionBounds);
+  external void updateCharacterBounds(
     int rangeStart,
     JSArray characterBounds,
   );
diff --git a/lib/src/dom/entries_api.dart b/lib/src/dom/entries_api.dart
index 2c200581..60e64af6 100644
--- a/lib/src/dom/entries_api.dart
+++ b/lib/src/dom/entries_api.dart
@@ -14,7 +14,7 @@ typedef FileCallback = JSFunction;
 class FileSystemEntry implements JSObject {}
 
 extension FileSystemEntryExtension on FileSystemEntry {
-  external JSVoid getParent([
+  external void getParent([
     FileSystemEntryCallback successCallback,
     ErrorCallback errorCallback,
   ]);
@@ -31,13 +31,13 @@ class FileSystemDirectoryEntry implements FileSystemEntry {}
 
 extension FileSystemDirectoryEntryExtension on FileSystemDirectoryEntry {
   external FileSystemDirectoryReader createReader();
-  external JSVoid getFile([
+  external void getFile([
     String? path,
     FileSystemFlags options,
     FileSystemEntryCallback successCallback,
     ErrorCallback errorCallback,
   ]);
-  external JSVoid getDirectory([
+  external void getDirectory([
     String? path,
     FileSystemFlags options,
     FileSystemEntryCallback successCallback,
@@ -67,7 +67,7 @@ extension FileSystemFlagsExtension on FileSystemFlags {
 class FileSystemDirectoryReader implements JSObject {}
 
 extension FileSystemDirectoryReaderExtension on FileSystemDirectoryReader {
-  external JSVoid readEntries(
+  external void readEntries(
     FileSystemEntriesCallback successCallback, [
     ErrorCallback errorCallback,
   ]);
@@ -78,7 +78,7 @@ extension FileSystemDirectoryReaderExtension on FileSystemDirectoryReader {
 class FileSystemFileEntry implements FileSystemEntry {}
 
 extension FileSystemFileEntryExtension on FileSystemFileEntry {
-  external JSVoid file(
+  external void file(
     FileCallback successCallback, [
     ErrorCallback errorCallback,
   ]);
diff --git a/lib/src/dom/ext_disjoint_timer_query.dart b/lib/src/dom/ext_disjoint_timer_query.dart
index bf133c04..25156367 100644
--- a/lib/src/dom/ext_disjoint_timer_query.dart
+++ b/lib/src/dom/ext_disjoint_timer_query.dart
@@ -26,14 +26,14 @@ class EXT_disjoint_timer_query implements JSObject {
 
 extension EXTDisjointTimerQueryExtension on EXT_disjoint_timer_query {
   external WebGLTimerQueryEXT? createQueryEXT();
-  external JSVoid deleteQueryEXT(WebGLTimerQueryEXT? query);
+  external void deleteQueryEXT(WebGLTimerQueryEXT? query);
   external bool isQueryEXT(WebGLTimerQueryEXT? query);
-  external JSVoid beginQueryEXT(
+  external void beginQueryEXT(
     GLenum target,
     WebGLTimerQueryEXT query,
   );
-  external JSVoid endQueryEXT(GLenum target);
-  external JSVoid queryCounterEXT(
+  external void endQueryEXT(GLenum target);
+  external void queryCounterEXT(
     WebGLTimerQueryEXT query,
     GLenum target,
   );
diff --git a/lib/src/dom/ext_disjoint_timer_query_webgl2.dart b/lib/src/dom/ext_disjoint_timer_query_webgl2.dart
index 57c12ee7..16cf9cf2 100644
--- a/lib/src/dom/ext_disjoint_timer_query_webgl2.dart
+++ b/lib/src/dom/ext_disjoint_timer_query_webgl2.dart
@@ -18,7 +18,7 @@ class EXT_disjoint_timer_query_webgl2 implements JSObject {
 
 extension EXTDisjointTimerQueryWebgl2Extension
     on EXT_disjoint_timer_query_webgl2 {
-  external JSVoid queryCounterEXT(
+  external void queryCounterEXT(
     WebGLQuery query,
     GLenum target,
   );
diff --git a/lib/src/dom/fenced_frame.dart b/lib/src/dom/fenced_frame.dart
index c4e0346b..e1c0e82d 100644
--- a/lib/src/dom/fenced_frame.dart
+++ b/lib/src/dom/fenced_frame.dart
@@ -6,10 +6,10 @@ import 'dart:js_interop';
 
 import 'html.dart';
 
-typedef FencedFrameConfigSize = JSAny?;
+typedef FencedFrameConfigSize = JSAny;
 typedef FencedFrameConfigURL = String;
-typedef UrnOrConfig = JSAny?;
-typedef ReportEventType = JSAny?;
+typedef UrnOrConfig = JSAny;
+typedef ReportEventType = JSAny;
 typedef OpaqueProperty = String;
 typedef FenceReportingDestination = String;
 
@@ -35,7 +35,7 @@ extension HTMLFencedFrameElementExtension on HTMLFencedFrameElement {
 class FencedFrameConfig implements JSObject {}
 
 extension FencedFrameConfigExtension on FencedFrameConfig {
-  external JSVoid setSharedStorageContext(String contextString);
+  external void setSharedStorageContext(String contextString);
   external FencedFrameConfigSize? get containerWidth;
   external FencedFrameConfigSize? get containerHeight;
   external FencedFrameConfigSize? get contentWidth;
@@ -73,7 +73,7 @@ extension FenceEventExtension on FenceEvent {
 class Fence implements JSObject {}
 
 extension FenceExtension on Fence {
-  external JSVoid reportEvent([ReportEventType event]);
-  external JSVoid setReportEventDataForAutomaticBeacons([FenceEvent event]);
+  external void reportEvent([ReportEventType event]);
+  external void setReportEventDataForAutomaticBeacons([FenceEvent event]);
   external JSArray getNestedConfigs();
 }
diff --git a/lib/src/dom/fetch.dart b/lib/src/dom/fetch.dart
index 9f8adbed..98bcac3c 100644
--- a/lib/src/dom/fetch.dart
+++ b/lib/src/dom/fetch.dart
@@ -11,10 +11,10 @@ import 'referrer_policy.dart';
 import 'streams.dart';
 import 'trust_token_api.dart';
 
-typedef HeadersInit = JSAny?;
-typedef XMLHttpRequestBodyInit = JSAny?;
-typedef BodyInit = JSAny?;
-typedef RequestInfo = JSAny?;
+typedef HeadersInit = JSAny;
+typedef XMLHttpRequestBodyInit = JSAny;
+typedef BodyInit = JSAny;
+typedef RequestInfo = JSAny;
 typedef RequestDestination = String;
 typedef RequestMode = String;
 typedef RequestCredentials = String;
@@ -31,15 +31,15 @@ class Headers implements JSObject {
 }
 
 extension HeadersExtension on Headers {
-  external JSVoid append(
+  external void append(
     String name,
     String value,
   );
-  external JSVoid delete(String name);
+  external void delete(String name);
   external String? get(String name);
   external JSArray getSetCookie();
   external bool has(String name);
-  external JSVoid set(
+  external void set(
     String name,
     String value,
   );
diff --git a/lib/src/dom/file_system_access.dart b/lib/src/dom/file_system_access.dart
index 657ea3df..5c98c9d6 100644
--- a/lib/src/dom/file_system_access.dart
+++ b/lib/src/dom/file_system_access.dart
@@ -7,7 +7,7 @@ import 'dart:js_interop';
 import 'fs.dart';
 import 'permissions.dart';
 
-typedef StartInDirectory = JSAny?;
+typedef StartInDirectory = JSAny;
 typedef FileSystemPermissionMode = String;
 typedef WellKnownDirectory = String;
 
@@ -49,15 +49,15 @@ extension FileSystemHandlePermissionDescriptorExtension
 class FilePickerAcceptType implements JSObject {
   external factory FilePickerAcceptType({
     String description,
-    JSAny? accept,
+    JSAny accept,
   });
 }
 
 extension FilePickerAcceptTypeExtension on FilePickerAcceptType {
   external set description(String value);
   external String get description;
-  external set accept(JSAny? value);
-  external JSAny? get accept;
+  external set accept(JSAny value);
+  external JSAny get accept;
 }
 
 @JS()
diff --git a/lib/src/dom/fileapi.dart b/lib/src/dom/fileapi.dart
index 566f6e71..036dff6e 100644
--- a/lib/src/dom/fileapi.dart
+++ b/lib/src/dom/fileapi.dart
@@ -9,7 +9,7 @@ import 'html.dart';
 import 'streams.dart';
 import 'webidl.dart';
 
-typedef BlobPart = JSAny?;
+typedef BlobPart = JSAny;
 typedef EndingType = String;
 
 @JS('Blob')
@@ -99,14 +99,14 @@ class FileReader implements EventTarget {
 }
 
 extension FileReaderExtension on FileReader {
-  external JSVoid readAsArrayBuffer(Blob blob);
-  external JSVoid readAsBinaryString(Blob blob);
-  external JSVoid readAsText(
+  external void readAsArrayBuffer(Blob blob);
+  external void readAsBinaryString(Blob blob);
+  external void readAsText(
     Blob blob, [
     String encoding,
   ]);
-  external JSVoid readAsDataURL(Blob blob);
-  external JSVoid abort();
+  external void readAsDataURL(Blob blob);
+  external void abort();
   external int get readyState;
   external JSAny? get result;
   external DOMException? get error;
diff --git a/lib/src/dom/filter_effects.dart b/lib/src/dom/filter_effects.dart
index d960f6ad..369823d0 100644
--- a/lib/src/dom/filter_effects.dart
+++ b/lib/src/dom/filter_effects.dart
@@ -246,7 +246,7 @@ class SVGFEDropShadowElement
     implements SVGElement, SVGFilterPrimitiveStandardAttributes {}
 
 extension SVGFEDropShadowElementExtension on SVGFEDropShadowElement {
-  external JSVoid setStdDeviation(
+  external void setStdDeviation(
     num stdDeviationX,
     num stdDeviationY,
   );
@@ -273,7 +273,7 @@ class SVGFEGaussianBlurElement
 }
 
 extension SVGFEGaussianBlurElementExtension on SVGFEGaussianBlurElement {
-  external JSVoid setStdDeviation(
+  external void setStdDeviation(
     num stdDeviationX,
     num stdDeviationY,
   );
diff --git a/lib/src/dom/fs.dart b/lib/src/dom/fs.dart
index e6f47570..b5e9a877 100644
--- a/lib/src/dom/fs.dart
+++ b/lib/src/dom/fs.dart
@@ -8,7 +8,7 @@ import 'file_system_access.dart';
 import 'streams.dart';
 import 'webidl.dart';
 
-typedef FileSystemWriteChunkType = JSAny?;
+typedef FileSystemWriteChunkType = JSAny;
 typedef FileSystemHandleKind = String;
 typedef WriteCommandType = String;
 
@@ -165,8 +165,8 @@ extension FileSystemSyncAccessHandleExtension on FileSystemSyncAccessHandle {
     AllowSharedBufferSource buffer, [
     FileSystemReadWriteOptions options,
   ]);
-  external JSVoid truncate(int newSize);
+  external void truncate(int newSize);
   external int getSize();
-  external JSVoid flush();
-  external JSVoid close();
+  external void flush();
+  external void close();
 }
diff --git a/lib/src/dom/generic_sensor.dart b/lib/src/dom/generic_sensor.dart
index 3f9bd770..6fea9ec1 100644
--- a/lib/src/dom/generic_sensor.dart
+++ b/lib/src/dom/generic_sensor.dart
@@ -16,8 +16,8 @@ typedef MockSensorType = String;
 class Sensor implements EventTarget {}
 
 extension SensorExtension on Sensor {
-  external JSVoid start();
-  external JSVoid stop();
+  external void start();
+  external void stop();
   external bool get activated;
   external bool get hasReading;
   external DOMHighResTimeStamp? get timestamp;
diff --git a/lib/src/dom/geolocation.dart b/lib/src/dom/geolocation.dart
index 836ebc80..84002433 100644
--- a/lib/src/dom/geolocation.dart
+++ b/lib/src/dom/geolocation.dart
@@ -14,7 +14,7 @@ typedef PositionErrorCallback = JSFunction;
 class Geolocation implements JSObject {}
 
 extension GeolocationExtension on Geolocation {
-  external JSVoid getCurrentPosition(
+  external void getCurrentPosition(
     PositionCallback successCallback, [
     PositionErrorCallback? errorCallback,
     PositionOptions options,
@@ -24,7 +24,7 @@ extension GeolocationExtension on Geolocation {
     PositionErrorCallback? errorCallback,
     PositionOptions options,
   ]);
-  external JSVoid clearWatch(int watchId);
+  external void clearWatch(int watchId);
 }
 
 @JS()
diff --git a/lib/src/dom/geometry.dart b/lib/src/dom/geometry.dart
index 3bbc1fa7..f1df51f8 100644
--- a/lib/src/dom/geometry.dart
+++ b/lib/src/dom/geometry.dart
@@ -203,7 +203,7 @@ extension DOMQuadInitExtension on DOMQuadInit {
 @JS('DOMMatrixReadOnly')
 @staticInterop
 class DOMMatrixReadOnly implements JSObject {
-  external factory DOMMatrixReadOnly([JSAny? init]);
+  external factory DOMMatrixReadOnly([JSAny init]);
 
   external static DOMMatrixReadOnly fromMatrix([DOMMatrixInit other]);
   external static DOMMatrixReadOnly fromFloat32Array(JSFloat32Array array32);
@@ -288,7 +288,7 @@ extension DOMMatrixReadOnlyExtension on DOMMatrixReadOnly {
 @JS('DOMMatrix')
 @staticInterop
 class DOMMatrix implements DOMMatrixReadOnly {
-  external factory DOMMatrix([JSAny? init]);
+  external factory DOMMatrix([JSAny init]);
 
   external static DOMMatrix fromMatrix([DOMMatrixInit other]);
   external static DOMMatrix fromFloat32Array(JSFloat32Array array32);
diff --git a/lib/src/dom/hr_time.dart b/lib/src/dom/hr_time.dart
index e08bf6da..c4196c5c 100644
--- a/lib/src/dom/hr_time.dart
+++ b/lib/src/dom/hr_time.dart
@@ -28,19 +28,19 @@ extension PerformanceExtension on Performance {
     String name, [
     String type,
   ]);
-  external JSVoid clearResourceTimings();
-  external JSVoid setResourceTimingBufferSize(int maxSize);
+  external void clearResourceTimings();
+  external void setResourceTimingBufferSize(int maxSize);
   external PerformanceMark mark(
     String markName, [
     PerformanceMarkOptions markOptions,
   ]);
-  external JSVoid clearMarks([String markName]);
+  external void clearMarks([String markName]);
   external PerformanceMeasure measure(
     String measureName, [
-    JSAny? startOrMeasureOptions,
+    JSAny startOrMeasureOptions,
     String endMark,
   ]);
-  external JSVoid clearMeasures([String measureName]);
+  external void clearMeasures([String measureName]);
   external EventCounts get eventCounts;
   external int get interactionCount;
   external DOMHighResTimeStamp get timeOrigin;
diff --git a/lib/src/dom/html.dart b/lib/src/dom/html.dart
index 94afd128..5cd5fffc 100644
--- a/lib/src/dom/html.dart
+++ b/lib/src/dom/html.dart
@@ -91,7 +91,7 @@ typedef OffscreenRenderingContext = JSObject;
 typedef EventHandler = EventHandlerNonNull?;
 typedef OnErrorEventHandler = OnErrorEventHandlerNonNull?;
 typedef OnBeforeUnloadEventHandler = OnBeforeUnloadEventHandlerNonNull?;
-typedef TimerHandler = JSAny?;
+typedef TimerHandler = JSAny;
 typedef ImageBitmapSource = JSObject;
 typedef MessageEventSource = JSObject;
 typedef BlobCallback = JSFunction;
@@ -165,11 +165,11 @@ extension RadioNodeListExtension on RadioNodeList {
 class HTMLOptionsCollection implements HTMLCollection {}
 
 extension HTMLOptionsCollectionExtension on HTMLOptionsCollection {
-  external JSVoid add(
+  external void add(
     JSObject element, [
     JSAny? before,
   ]);
-  external JSVoid remove(int index);
+  external void remove(int index);
   external set length(int value);
   external int get length;
   external set selectedIndex(int value);
@@ -199,10 +199,10 @@ class HTMLElement
 }
 
 extension HTMLElementExtension on HTMLElement {
-  external JSVoid click();
+  external void click();
   external ElementInternals attachInternals();
-  external JSVoid showPopover();
-  external JSVoid hidePopover();
+  external void showPopover();
+  external void hidePopover();
   external bool togglePopover([bool force]);
   external Element? get offsetParent;
   external int get offsetTop;
@@ -249,8 +249,8 @@ class HTMLUnknownElement implements HTMLElement {}
 class HTMLOrSVGElement implements JSObject {}
 
 extension HTMLOrSVGElementExtension on HTMLOrSVGElement {
-  external JSVoid focus([FocusOptions options]);
-  external JSVoid blur();
+  external void focus([FocusOptions options]);
+  external void blur();
   external DOMStringMap get dataset;
   external set nonce(String value);
   external String get nonce;
@@ -838,7 +838,7 @@ extension HTMLObjectElementExtension on HTMLObjectElement {
   external Document? getSVGDocument();
   external bool checkValidity();
   external bool reportValidity();
-  external JSVoid setCustomValidity(String error);
+  external void setCustomValidity(String error);
   external set data(String value);
   external String get data;
   external set type(String value);
@@ -889,7 +889,7 @@ extension HTMLVideoElementExtension on HTMLVideoElement {
   external VideoPlaybackQuality getVideoPlaybackQuality();
   external JSPromise requestPictureInPicture();
   external int requestVideoFrameCallback(VideoFrameRequestCallback callback);
-  external JSVoid cancelVideoFrameCallback(int handle);
+  external void cancelVideoFrameCallback(int handle);
   external set width(int value);
   external int get width;
   external set height(int value);
@@ -959,12 +959,12 @@ class HTMLMediaElement implements HTMLElement {
 extension HTMLMediaElementExtension on HTMLMediaElement {
   external JSPromise setSinkId(String sinkId);
   external JSPromise setMediaKeys(MediaKeys? mediaKeys);
-  external JSVoid load();
+  external void load();
   external CanPlayTypeResult canPlayType(String type);
-  external JSVoid fastSeek(num time);
+  external void fastSeek(num time);
   external JSObject getStartDate();
   external JSPromise play();
-  external JSVoid pause();
+  external void pause();
   external TextTrack addTextTrack(
     TextTrackKind kind, [
     String label,
@@ -1117,8 +1117,8 @@ extension TextTrackListExtension on TextTrackList {
 class TextTrack implements EventTarget {}
 
 extension TextTrackExtension on TextTrack {
-  external JSVoid addCue(TextTrackCue cue);
-  external JSVoid removeCue(TextTrackCue cue);
+  external void addCue(TextTrackCue cue);
+  external void removeCue(TextTrackCue cue);
   external TextTrackKind get kind;
   external String get label;
   external String get language;
@@ -1245,14 +1245,14 @@ class HTMLTableElement implements HTMLElement {
 
 extension HTMLTableElementExtension on HTMLTableElement {
   external HTMLTableCaptionElement createCaption();
-  external JSVoid deleteCaption();
+  external void deleteCaption();
   external HTMLTableSectionElement createTHead();
-  external JSVoid deleteTHead();
+  external void deleteTHead();
   external HTMLTableSectionElement createTFoot();
-  external JSVoid deleteTFoot();
+  external void deleteTFoot();
   external HTMLTableSectionElement createTBody();
   external HTMLTableRowElement insertRow([int index]);
-  external JSVoid deleteRow(int index);
+  external void deleteRow(int index);
   external set caption(HTMLTableCaptionElement? value);
   external HTMLTableCaptionElement? get caption;
   external set tHead(HTMLTableSectionElement? value);
@@ -1321,7 +1321,7 @@ class HTMLTableSectionElement implements HTMLElement {
 
 extension HTMLTableSectionElementExtension on HTMLTableSectionElement {
   external HTMLTableRowElement insertRow([int index]);
-  external JSVoid deleteRow(int index);
+  external void deleteRow(int index);
   external HTMLCollection get rows;
   external set align(String value);
   external String get align;
@@ -1341,7 +1341,7 @@ class HTMLTableRowElement implements HTMLElement {
 
 extension HTMLTableRowElementExtension on HTMLTableRowElement {
   external HTMLTableCellElement insertCell([int index]);
-  external JSVoid deleteCell(int index);
+  external void deleteCell(int index);
   external int get rowIndex;
   external int get sectionRowIndex;
   external HTMLCollection get cells;
@@ -1402,9 +1402,9 @@ class HTMLFormElement implements HTMLElement {
 }
 
 extension HTMLFormElementExtension on HTMLFormElement {
-  external JSVoid submit();
-  external JSVoid requestSubmit([HTMLElement? submitter]);
-  external JSVoid reset();
+  external void submit();
+  external void requestSubmit([HTMLElement? submitter]);
+  external void reset();
   external bool checkValidity();
   external bool reportValidity();
   external set acceptCharset(String value);
@@ -1452,24 +1452,24 @@ class HTMLInputElement implements HTMLElement, PopoverInvokerElement {
 }
 
 extension HTMLInputElementExtension on HTMLInputElement {
-  external JSVoid stepUp([int n]);
-  external JSVoid stepDown([int n]);
+  external void stepUp([int n]);
+  external void stepDown([int n]);
   external bool checkValidity();
   external bool reportValidity();
-  external JSVoid setCustomValidity(String error);
-  external JSVoid select();
-  external JSVoid setRangeText(
+  external void setCustomValidity(String error);
+  external void select();
+  external void setRangeText(
     String replacement, [
     int start,
     int end,
     SelectionMode selectionMode,
   ]);
-  external JSVoid setSelectionRange(
+  external void setSelectionRange(
     int start,
     int end, [
     String direction,
   ]);
-  external JSVoid showPicker();
+  external void showPicker();
   external set webkitdirectory(bool value);
   external bool get webkitdirectory;
   external JSArray get webkitEntries;
@@ -1570,7 +1570,7 @@ class HTMLButtonElement implements HTMLElement, PopoverInvokerElement {
 extension HTMLButtonElementExtension on HTMLButtonElement {
   external bool checkValidity();
   external bool reportValidity();
-  external JSVoid setCustomValidity(String error);
+  external void setCustomValidity(String error);
   external set disabled(bool value);
   external bool get disabled;
   external HTMLFormElement? get form;
@@ -1605,14 +1605,14 @@ class HTMLSelectElement implements HTMLElement {
 extension HTMLSelectElementExtension on HTMLSelectElement {
   external HTMLOptionElement? item(int index);
   external HTMLOptionElement? namedItem(String name);
-  external JSVoid add(
+  external void add(
     JSObject element, [
     JSAny? before,
   ]);
-  external JSVoid remove([int index]);
+  external void remove([int index]);
   external bool checkValidity();
   external bool reportValidity();
-  external JSVoid setCustomValidity(String error);
+  external void setCustomValidity(String error);
   external set autocomplete(String value);
   external String get autocomplete;
   external set disabled(bool value);
@@ -1696,15 +1696,15 @@ class HTMLTextAreaElement implements HTMLElement {
 extension HTMLTextAreaElementExtension on HTMLTextAreaElement {
   external bool checkValidity();
   external bool reportValidity();
-  external JSVoid setCustomValidity(String error);
-  external JSVoid select();
-  external JSVoid setRangeText(
+  external void setCustomValidity(String error);
+  external void select();
+  external void setRangeText(
     String replacement, [
     int start,
     int end,
     SelectionMode selectionMode,
   ]);
-  external JSVoid setSelectionRange(
+  external void setSelectionRange(
     int start,
     int end, [
     String direction,
@@ -1761,7 +1761,7 @@ class HTMLOutputElement implements HTMLElement {
 extension HTMLOutputElementExtension on HTMLOutputElement {
   external bool checkValidity();
   external bool reportValidity();
-  external JSVoid setCustomValidity(String error);
+  external void setCustomValidity(String error);
   external DOMTokenList get htmlFor;
   external HTMLFormElement? get form;
   external set name(String value);
@@ -1823,7 +1823,7 @@ class HTMLFieldSetElement implements HTMLElement {
 extension HTMLFieldSetElementExtension on HTMLFieldSetElement {
   external bool checkValidity();
   external bool reportValidity();
-  external JSVoid setCustomValidity(String error);
+  external void setCustomValidity(String error);
   external set disabled(bool value);
   external bool get disabled;
   external HTMLFormElement? get form;
@@ -1936,9 +1936,9 @@ class HTMLDialogElement implements HTMLElement {
 }
 
 extension HTMLDialogElementExtension on HTMLDialogElement {
-  external JSVoid show();
-  external JSVoid showModal();
-  external JSVoid close([String returnValue]);
+  external void show();
+  external void showModal();
+  external void close([String returnValue]);
   external set open(bool value);
   external bool get open;
   external set returnValue(String value);
@@ -2002,7 +2002,7 @@ class HTMLSlotElement implements HTMLElement {
 extension HTMLSlotElementExtension on HTMLSlotElement {
   external JSArray assignedNodes([AssignedNodesOptions options]);
   external JSArray assignedElements([AssignedNodesOptions options]);
-  external JSVoid assign(JSObject nodes);
+  external void assign(JSObject nodes);
   external set name(String value);
   external String get name;
 }
@@ -2034,7 +2034,7 @@ extension HTMLCanvasElementExtension on HTMLCanvasElement {
     String type,
     JSAny? quality,
   ]);
-  external JSVoid toBlob(
+  external void toBlob(
     BlobCallback callback, [
     String type,
     JSAny? quality,
@@ -2102,9 +2102,9 @@ extension CanvasRenderingContext2DExtension on CanvasRenderingContext2D {
 class CanvasState implements JSObject {}
 
 extension CanvasStateExtension on CanvasState {
-  external JSVoid save();
-  external JSVoid restore();
-  external JSVoid reset();
+  external void save();
+  external void restore();
+  external void reset();
   external bool isContextLost();
 }
 
@@ -2113,16 +2113,16 @@ extension CanvasStateExtension on CanvasState {
 class CanvasTransform implements JSObject {}
 
 extension CanvasTransformExtension on CanvasTransform {
-  external JSVoid scale(
+  external void scale(
     num x,
     num y,
   );
-  external JSVoid rotate(num angle);
-  external JSVoid translate(
+  external void rotate(num angle);
+  external void translate(
     num x,
     num y,
   );
-  external JSVoid transform(
+  external void transform(
     num a,
     num b,
     num c,
@@ -2131,15 +2131,15 @@ extension CanvasTransformExtension on CanvasTransform {
     num f,
   );
   external DOMMatrix getTransform();
-  external JSVoid setTransform([
-    JSAny? aOrTransform,
+  external void setTransform([
+    JSAny aOrTransform,
     num b,
     num c,
     num d,
     num e,
     num f,
   ]);
-  external JSVoid resetTransform();
+  external void resetTransform();
 }
 
 @JS('CanvasCompositing')
@@ -2192,10 +2192,10 @@ extension CanvasFillStrokeStylesExtension on CanvasFillStrokeStyles {
     CanvasImageSource image,
     String repetition,
   );
-  external set strokeStyle(JSAny? value);
-  external JSAny? get strokeStyle;
-  external set fillStyle(JSAny? value);
-  external JSAny? get fillStyle;
+  external set strokeStyle(JSAny value);
+  external JSAny get strokeStyle;
+  external set fillStyle(JSAny value);
+  external JSAny get fillStyle;
 }
 
 @JS('CanvasShadowStyles')
@@ -2227,19 +2227,19 @@ extension CanvasFiltersExtension on CanvasFilters {
 class CanvasRect implements JSObject {}
 
 extension CanvasRectExtension on CanvasRect {
-  external JSVoid clearRect(
+  external void clearRect(
     num x,
     num y,
     num w,
     num h,
   );
-  external JSVoid fillRect(
+  external void fillRect(
     num x,
     num y,
     num w,
     num h,
   );
-  external JSVoid strokeRect(
+  external void strokeRect(
     num x,
     num y,
     num w,
@@ -2252,24 +2252,24 @@ extension CanvasRectExtension on CanvasRect {
 class CanvasDrawPath implements JSObject {}
 
 extension CanvasDrawPathExtension on CanvasDrawPath {
-  external JSVoid beginPath();
-  external JSVoid fill([
-    JSAny? fillRuleOrPath,
+  external void beginPath();
+  external void fill([
+    JSAny fillRuleOrPath,
     CanvasFillRule fillRule,
   ]);
-  external JSVoid stroke([Path2D path]);
-  external JSVoid clip([
-    JSAny? fillRuleOrPath,
+  external void stroke([Path2D path]);
+  external void clip([
+    JSAny fillRuleOrPath,
     CanvasFillRule fillRule,
   ]);
   external bool isPointInPath(
-    JSAny? pathOrX,
+    JSAny pathOrX,
     num xOrY, [
-    JSAny? fillRuleOrY,
+    JSAny fillRuleOrY,
     CanvasFillRule fillRule,
   ]);
   external bool isPointInStroke(
-    JSAny? pathOrX,
+    JSAny pathOrX,
     num xOrY, [
     num y,
   ]);
@@ -2280,11 +2280,11 @@ extension CanvasDrawPathExtension on CanvasDrawPath {
 class CanvasUserInterface implements JSObject {}
 
 extension CanvasUserInterfaceExtension on CanvasUserInterface {
-  external JSVoid drawFocusIfNeeded(
+  external void drawFocusIfNeeded(
     JSObject elementOrPath, [
     Element element,
   ]);
-  external JSVoid scrollPathIntoView([Path2D path]);
+  external void scrollPathIntoView([Path2D path]);
 }
 
 @JS('CanvasText')
@@ -2292,13 +2292,13 @@ extension CanvasUserInterfaceExtension on CanvasUserInterface {
 class CanvasText implements JSObject {}
 
 extension CanvasTextExtension on CanvasText {
-  external JSVoid fillText(
+  external void fillText(
     String text,
     num x,
     num y, [
     num maxWidth,
   ]);
-  external JSVoid strokeText(
+  external void strokeText(
     String text,
     num x,
     num y, [
@@ -2312,7 +2312,7 @@ extension CanvasTextExtension on CanvasText {
 class CanvasDrawImage implements JSObject {}
 
 extension CanvasDrawImageExtension on CanvasDrawImage {
-  external JSVoid drawImage(
+  external void drawImage(
     CanvasImageSource image,
     num dxOrSx,
     num dyOrSy, [
@@ -2331,7 +2331,7 @@ class CanvasImageData implements JSObject {}
 
 extension CanvasImageDataExtension on CanvasImageData {
   external ImageData createImageData(
-    JSAny? imagedataOrSw, [
+    JSAny imagedataOrSw, [
     int sh,
     ImageDataSettings settings,
   ]);
@@ -2342,7 +2342,7 @@ extension CanvasImageDataExtension on CanvasImageData {
     int sh, [
     ImageDataSettings settings,
   ]);
-  external JSVoid putImageData(
+  external void putImageData(
     ImageData imagedata,
     int dx,
     int dy, [
@@ -2358,7 +2358,7 @@ extension CanvasImageDataExtension on CanvasImageData {
 class CanvasPathDrawingStyles implements JSObject {}
 
 extension CanvasPathDrawingStylesExtension on CanvasPathDrawingStyles {
-  external JSVoid setLineDash(JSArray segments);
+  external void setLineDash(JSArray segments);
   external JSArray getLineDash();
   external set lineWidth(num value);
   external num get lineWidth;
@@ -2404,22 +2404,22 @@ extension CanvasTextDrawingStylesExtension on CanvasTextDrawingStyles {
 class CanvasPath implements JSObject {}
 
 extension CanvasPathExtension on CanvasPath {
-  external JSVoid closePath();
-  external JSVoid moveTo(
+  external void closePath();
+  external void moveTo(
     num x,
     num y,
   );
-  external JSVoid lineTo(
+  external void lineTo(
     num x,
     num y,
   );
-  external JSVoid quadraticCurveTo(
+  external void quadraticCurveTo(
     num cpx,
     num cpy,
     num x,
     num y,
   );
-  external JSVoid bezierCurveTo(
+  external void bezierCurveTo(
     num cp1x,
     num cp1y,
     num cp2x,
@@ -2427,27 +2427,27 @@ extension CanvasPathExtension on CanvasPath {
     num x,
     num y,
   );
-  external JSVoid arcTo(
+  external void arcTo(
     num x1,
     num y1,
     num x2,
     num y2,
     num radius,
   );
-  external JSVoid rect(
+  external void rect(
     num x,
     num y,
     num w,
     num h,
   );
-  external JSVoid roundRect(
+  external void roundRect(
     num x,
     num y,
     num w,
     num h, [
-    JSAny? radii,
+    JSAny radii,
   ]);
-  external JSVoid arc(
+  external void arc(
     num x,
     num y,
     num radius,
@@ -2455,7 +2455,7 @@ extension CanvasPathExtension on CanvasPath {
     num endAngle, [
     bool counterclockwise,
   ]);
-  external JSVoid ellipse(
+  external void ellipse(
     num x,
     num y,
     num radiusX,
@@ -2472,7 +2472,7 @@ extension CanvasPathExtension on CanvasPath {
 class CanvasGradient implements JSObject {}
 
 extension CanvasGradientExtension on CanvasGradient {
-  external JSVoid addColorStop(
+  external void addColorStop(
     num offset,
     String color,
   );
@@ -2483,7 +2483,7 @@ extension CanvasGradientExtension on CanvasGradient {
 class CanvasPattern implements JSObject {}
 
 extension CanvasPatternExtension on CanvasPattern {
-  external JSVoid setTransform([DOMMatrix2DInit transform]);
+  external void setTransform([DOMMatrix2DInit transform]);
 }
 
 @JS('TextMetrics')
@@ -2521,9 +2521,9 @@ extension ImageDataSettingsExtension on ImageDataSettings {
 @staticInterop
 class ImageData implements JSObject {
   external factory ImageData(
-    JSAny? dataOrSw,
+    JSAny dataOrSw,
     int shOrSw, [
-    JSAny? settingsOrSh,
+    JSAny settingsOrSh,
     ImageDataSettings settings,
   ]);
 }
@@ -2538,11 +2538,11 @@ extension ImageDataExtension on ImageData {
 @JS('Path2D')
 @staticInterop
 class Path2D implements CanvasPath {
-  external factory Path2D([JSAny? path]);
+  external factory Path2D([JSAny path]);
 }
 
 extension Path2DExtension on Path2D {
-  external JSVoid addPath(
+  external void addPath(
     Path2D path, [
     DOMMatrix2DInit transform,
   ]);
@@ -2553,7 +2553,7 @@ extension Path2DExtension on Path2D {
 class ImageBitmapRenderingContext implements JSObject {}
 
 extension ImageBitmapRenderingContextExtension on ImageBitmapRenderingContext {
-  external JSVoid transferFromImageBitmap(ImageBitmap? bitmap);
+  external void transferFromImageBitmap(ImageBitmap? bitmap);
   external JSObject get canvas;
 }
 
@@ -2635,7 +2635,7 @@ class OffscreenCanvasRenderingContext2D
 
 extension OffscreenCanvasRenderingContext2DExtension
     on OffscreenCanvasRenderingContext2D {
-  external JSVoid commit();
+  external void commit();
   external OffscreenCanvas get canvas;
 }
 
@@ -2644,7 +2644,7 @@ extension OffscreenCanvasRenderingContext2DExtension
 class CustomElementRegistry implements JSObject {}
 
 extension CustomElementRegistryExtension on CustomElementRegistry {
-  external JSVoid define(
+  external void define(
     String name,
     CustomElementConstructor constructor, [
     ElementDefinitionOptions options,
@@ -2652,7 +2652,7 @@ extension CustomElementRegistryExtension on CustomElementRegistry {
   external CustomElementConstructor? get(String name);
   external String? getName(CustomElementConstructor constructor);
   external JSPromise whenDefined(String name);
-  external JSVoid upgrade(Node root);
+  external void upgrade(Node root);
 }
 
 @JS()
@@ -2674,11 +2674,11 @@ extension ElementDefinitionOptionsExtension on ElementDefinitionOptions {
 class ElementInternals implements ARIAMixin {}
 
 extension ElementInternalsExtension on ElementInternals {
-  external JSVoid setFormValue(
+  external void setFormValue(
     JSAny? value, [
     JSAny? state,
   ]);
-  external JSVoid setValidity([
+  external void setValidity([
     ValidityStateFlags flags,
     String message,
     HTMLElement anchor,
@@ -2826,17 +2826,17 @@ class DataTransfer implements JSObject {
 }
 
 extension DataTransferExtension on DataTransfer {
-  external JSVoid setDragImage(
+  external void setDragImage(
     Element image,
     int x,
     int y,
   );
   external String getData(String format);
-  external JSVoid setData(
+  external void setData(
     String format,
     String data,
   );
-  external JSVoid clearData([String format]);
+  external void clearData([String format]);
   external set dropEffect(String value);
   external String get dropEffect;
   external set effectAllowed(String value);
@@ -2852,11 +2852,11 @@ class DataTransferItemList implements JSObject {}
 
 extension DataTransferItemListExtension on DataTransferItemList {
   external DataTransferItem? add(
-    JSAny? data, [
+    JSAny data, [
     String type,
   ]);
-  external JSVoid remove(int index);
-  external JSVoid clear();
+  external void remove(int index);
+  external void clear();
   external int get length;
 }
 
@@ -2867,7 +2867,7 @@ class DataTransferItem implements JSObject {}
 extension DataTransferItemExtension on DataTransferItem {
   external FileSystemEntry? webkitGetAsEntry();
   external JSPromise getAsFileSystemHandle();
-  external JSVoid getAsString(FunctionStringCallback? callback);
+  external void getAsString(FunctionStringCallback? callback);
   external File? getAsFile();
   external String get kind;
   external String get type;
@@ -2925,34 +2925,34 @@ class Window
         WindowLocalStorage {}
 
 extension WindowExtension on Window {
-  external JSVoid navigate(SpatialNavigationDirection dir);
+  external void navigate(SpatialNavigationDirection dir);
   external MediaQueryList matchMedia(String query);
-  external JSVoid moveTo(
+  external void moveTo(
     int x,
     int y,
   );
-  external JSVoid moveBy(
+  external void moveBy(
     int x,
     int y,
   );
-  external JSVoid resizeTo(
+  external void resizeTo(
     int width,
     int height,
   );
-  external JSVoid resizeBy(
+  external void resizeBy(
     int x,
     int y,
   );
-  external JSVoid scroll([
-    JSAny? optionsOrX,
+  external void scroll([
+    JSAny optionsOrX,
     num y,
   ]);
-  external JSVoid scrollTo([
-    JSAny? optionsOrX,
+  external void scrollTo([
+    JSAny optionsOrX,
     num y,
   ]);
-  external JSVoid scrollBy([
-    JSAny? optionsOrX,
+  external void scrollBy([
+    JSAny optionsOrX,
     num y,
   ]);
   external CSSStyleDeclaration getComputedStyle(
@@ -2963,35 +2963,35 @@ extension WindowExtension on Window {
   external JSPromise showOpenFilePicker([OpenFilePickerOptions options]);
   external JSPromise showSaveFilePicker([SaveFilePickerOptions options]);
   external JSPromise showDirectoryPicker([DirectoryPickerOptions options]);
-  external JSVoid close();
-  external JSVoid stop();
-  external JSVoid focus();
-  external JSVoid blur();
+  external void close();
+  external void stop();
+  external void focus();
+  external void blur();
   external Window? open([
     String url,
     String target,
     String features,
   ]);
-  external JSVoid alert([String message]);
+  external void alert([String message]);
   external bool confirm([String message]);
   external String? prompt([
     String message,
     String default_,
   ]);
-  external JSVoid print();
-  external JSVoid postMessage(
+  external void print();
+  external void postMessage(
     JSAny? message, [
-    JSAny? optionsOrTargetOrigin,
+    JSAny optionsOrTargetOrigin,
     JSArray transfer,
   ]);
-  external JSVoid captureEvents();
-  external JSVoid releaseEvents();
+  external void captureEvents();
+  external void releaseEvents();
   external JSPromise queryLocalFonts([QueryOptions options]);
   external int requestIdleCallback(
     IdleRequestCallback callback, [
     IdleRequestOptions options,
   ]);
-  external JSVoid cancelIdleCallback(int handle);
+  external void cancelIdleCallback(int handle);
   external Selection? getSelection();
   external JSPromise getScreenDetails();
   external int get orientation;
@@ -3086,9 +3086,9 @@ extension BarPropExtension on BarProp {
 class Location implements JSObject {}
 
 extension LocationExtension on Location {
-  external JSVoid assign(String url);
-  external JSVoid replace(String url);
-  external JSVoid reload();
+  external void assign(String url);
+  external void replace(String url);
+  external void reload();
   external set href(String value);
   external String get href;
   external String get origin;
@@ -3114,15 +3114,15 @@ extension LocationExtension on Location {
 class History implements JSObject {}
 
 extension HistoryExtension on History {
-  external JSVoid go([int delta]);
-  external JSVoid back();
-  external JSVoid forward();
-  external JSVoid pushState(
+  external void go([int delta]);
+  external void back();
+  external void forward();
+  external void pushState(
     JSAny? data,
     String unused, [
     String? url,
   ]);
-  external JSVoid replaceState(
+  external void replaceState(
     JSAny? data,
     String unused, [
     String? url,
@@ -3139,8 +3139,7 @@ class Navigation implements EventTarget {}
 
 extension NavigationExtension on Navigation {
   external JSArray entries();
-  external JSVoid updateCurrentEntry(
-      NavigationUpdateCurrentEntryOptions options);
+  external void updateCurrentEntry(NavigationUpdateCurrentEntryOptions options);
   external NavigationResult navigate(
     String url, [
     NavigationNavigateOptions options,
@@ -3272,8 +3271,8 @@ class NavigateEvent implements Event {
 }
 
 extension NavigateEventExtension on NavigateEvent {
-  external JSVoid intercept([NavigationInterceptOptions options]);
-  external JSVoid scroll();
+  external void intercept([NavigationInterceptOptions options]);
+  external void scroll();
   external NavigationType get navigationType;
   external NavigationDestination get destination;
   external bool get canIntercept;
@@ -3826,7 +3825,7 @@ extension WindowOrWorkerGlobalScopeExtension on WindowOrWorkerGlobalScope {
     RequestInfo input, [
     RequestInit init,
   ]);
-  external JSVoid reportError(JSAny? e);
+  external void reportError(JSAny? e);
   external String btoa(String data);
   external String atob(String data);
   external int setTimeout(
@@ -3834,17 +3833,17 @@ extension WindowOrWorkerGlobalScopeExtension on WindowOrWorkerGlobalScope {
     JSAny? arguments, [
     int timeout,
   ]);
-  external JSVoid clearTimeout([int id]);
+  external void clearTimeout([int id]);
   external int setInterval(
     TimerHandler handler,
     JSAny? arguments, [
     int timeout,
   ]);
-  external JSVoid clearInterval([int id]);
-  external JSVoid queueMicrotask(VoidFunction callback);
+  external void clearInterval([int id]);
+  external void queueMicrotask(VoidFunction callback);
   external JSPromise createImageBitmap(
     ImageBitmapSource image, [
-    JSAny? optionsOrSx,
+    JSAny optionsOrSx,
     int sy,
     int sw,
     int sh,
@@ -3901,7 +3900,7 @@ class Navigator
         NavigatorML {}
 
 extension NavigatorExtension on Navigator {
-  external AutoplayPolicy getAutoplayPolicy(JSAny? contextOrElementOrType);
+  external AutoplayPolicy getAutoplayPolicy(JSAny contextOrElementOrType);
   external JSPromise getBattery();
   external bool sendBeacon(
     String url, [
@@ -3913,11 +3912,11 @@ extension NavigatorExtension on Navigator {
   );
   external JSPromise deprecatedReplaceInURN(
     UrnOrConfig urnOrConfig,
-    JSAny? replacements,
+    JSAny replacements,
   );
   external JSArray getGamepads();
   external JSPromise getInstalledRelatedApps();
-  external JSVoid getUserMedia(
+  external void getUserMedia(
     MediaStreamConstraints constraints,
     NavigatorUserMediaSuccessCallback successCallback,
     NavigatorUserMediaErrorCallback errorCallback,
@@ -3925,7 +3924,7 @@ extension NavigatorExtension on Navigator {
   external JSPromise joinAdInterestGroup(AuctionAdInterestGroup group);
   external JSPromise leaveAdInterestGroup([AuctionAdInterestGroupKey group]);
   external JSPromise runAdAuction(AuctionAdConfig config);
-  external JSVoid updateAdInterestGroups();
+  external void updateAdInterestGroups();
   external bool vibrate(VibratePattern pattern);
   external JSPromise share([ShareData data]);
   external bool canShare([ShareData data]);
@@ -3997,11 +3996,11 @@ extension NavigatorOnLineExtension on NavigatorOnLine {
 class NavigatorContentUtils implements JSObject {}
 
 extension NavigatorContentUtilsExtension on NavigatorContentUtils {
-  external JSVoid registerProtocolHandler(
+  external void registerProtocolHandler(
     String scheme,
     String url,
   );
-  external JSVoid unregisterProtocolHandler(
+  external void unregisterProtocolHandler(
     String scheme,
     String url,
   );
@@ -4031,7 +4030,7 @@ extension NavigatorPluginsExtension on NavigatorPlugins {
 class PluginArray implements JSObject {}
 
 extension PluginArrayExtension on PluginArray {
-  external JSVoid refresh();
+  external void refresh();
   external Plugin? item(int index);
   external Plugin? namedItem(String name);
   external int get length;
@@ -4076,7 +4075,7 @@ extension MimeTypeExtension on MimeType {
 class ImageBitmap implements JSObject {}
 
 extension ImageBitmapExtension on ImageBitmap {
-  external JSVoid close();
+  external void close();
   external int get width;
   external int get height;
 }
@@ -4116,7 +4115,7 @@ class AnimationFrameProvider implements JSObject {}
 
 extension AnimationFrameProviderExtension on AnimationFrameProvider {
   external int requestAnimationFrame(FrameRequestCallback callback);
-  external JSVoid cancelAnimationFrame(int handle);
+  external void cancelAnimationFrame(int handle);
 }
 
 @JS('MessageEvent')
@@ -4129,7 +4128,7 @@ class MessageEvent implements Event {
 }
 
 extension MessageEventExtension on MessageEvent {
-  external JSVoid initMessageEvent(
+  external void initMessageEvent(
     String type, [
     bool bubbles,
     bool cancelable,
@@ -4186,7 +4185,7 @@ class EventSource implements EventTarget {
 }
 
 extension EventSourceExtension on EventSource {
-  external JSVoid close();
+  external void close();
   external String get url;
   external bool get withCredentials;
   external int get readyState;
@@ -4226,12 +4225,12 @@ extension MessageChannelExtension on MessageChannel {
 class MessagePort implements EventTarget {}
 
 extension MessagePortExtension on MessagePort {
-  external JSVoid postMessage(
+  external void postMessage(
     JSAny? message, [
     JSObject optionsOrTransfer,
   ]);
-  external JSVoid start();
-  external JSVoid close();
+  external void start();
+  external void close();
   external set onmessage(EventHandler value);
   external EventHandler get onmessage;
   external set onmessageerror(EventHandler value);
@@ -4257,8 +4256,8 @@ class BroadcastChannel implements EventTarget {
 }
 
 extension BroadcastChannelExtension on BroadcastChannel {
-  external JSVoid postMessage(JSAny? message);
-  external JSVoid close();
+  external void postMessage(JSAny? message);
+  external void close();
   external String get name;
   external set onmessage(EventHandler value);
   external EventHandler get onmessage;
@@ -4272,7 +4271,7 @@ class WorkerGlobalScope
     implements EventTarget, FontFaceSource, WindowOrWorkerGlobalScope {}
 
 extension WorkerGlobalScopeExtension on WorkerGlobalScope {
-  external JSVoid importScripts(String urls);
+  external void importScripts(String urls);
   external WorkerGlobalScope get self;
   external WorkerLocation get location;
   external WorkerNavigator get navigator;
@@ -4296,11 +4295,11 @@ class DedicatedWorkerGlobalScope
     implements WorkerGlobalScope, AnimationFrameProvider {}
 
 extension DedicatedWorkerGlobalScopeExtension on DedicatedWorkerGlobalScope {
-  external JSVoid postMessage(
+  external void postMessage(
     JSAny? message, [
     JSObject optionsOrTransfer,
   ]);
-  external JSVoid close();
+  external void close();
   external String get name;
   external set onmessage(EventHandler value);
   external EventHandler get onmessage;
@@ -4315,7 +4314,7 @@ extension DedicatedWorkerGlobalScopeExtension on DedicatedWorkerGlobalScope {
 class SharedWorkerGlobalScope implements WorkerGlobalScope {}
 
 extension SharedWorkerGlobalScopeExtension on SharedWorkerGlobalScope {
-  external JSVoid close();
+  external void close();
   external String get name;
   external set onconnect(EventHandler value);
   external EventHandler get onconnect;
@@ -4340,8 +4339,8 @@ class Worker implements EventTarget, AbstractWorker {
 }
 
 extension WorkerExtension on Worker {
-  external JSVoid terminate();
-  external JSVoid postMessage(
+  external void terminate();
+  external void postMessage(
     JSAny? message, [
     JSObject optionsOrTransfer,
   ]);
@@ -4376,7 +4375,7 @@ extension WorkerOptionsExtension on WorkerOptions {
 class SharedWorker implements EventTarget, AbstractWorker {
   external factory SharedWorker(
     String scriptURL, [
-    JSAny? options,
+    JSAny options,
   ]);
 }
 
@@ -4469,12 +4468,12 @@ class Storage implements JSObject {}
 extension StorageExtension on Storage {
   external String? key(int index);
   external String? getItem(String key);
-  external JSVoid setItem(
+  external void setItem(
     String key,
     String value,
   );
-  external JSVoid removeItem(String key);
-  external JSVoid clear();
+  external void removeItem(String key);
+  external void clear();
   external int get length;
 }
 
@@ -4504,7 +4503,7 @@ class StorageEvent implements Event {
 }
 
 extension StorageEventExtension on StorageEvent {
-  external JSVoid initStorageEvent(
+  external void initStorageEvent(
     String type, [
     bool bubbles,
     bool cancelable,
@@ -4554,8 +4553,8 @@ class HTMLMarqueeElement implements HTMLElement {
 }
 
 extension HTMLMarqueeElementExtension on HTMLMarqueeElement {
-  external JSVoid start();
-  external JSVoid stop();
+  external void start();
+  external void stop();
   external set behavior(String value);
   external String get behavior;
   external set bgColor(String value);
@@ -4668,6 +4667,6 @@ extension HTMLParamElementExtension on HTMLParamElement {
 class External implements JSObject {}
 
 extension ExternalExtension on External {
-  external JSVoid AddSearchProvider();
-  external JSVoid IsSearchProviderInstalled();
+  external void AddSearchProvider();
+  external void IsSearchProviderInstalled();
 }
diff --git a/lib/src/dom/indexeddb.dart b/lib/src/dom/indexeddb.dart
index 64feffcc..dc44a7f7 100644
--- a/lib/src/dom/indexeddb.dart
+++ b/lib/src/dom/indexeddb.dart
@@ -111,16 +111,16 @@ class IDBDatabase implements EventTarget {}
 
 extension IDBDatabaseExtension on IDBDatabase {
   external IDBTransaction transaction(
-    JSAny? storeNames, [
+    JSAny storeNames, [
     IDBTransactionMode mode,
     IDBTransactionOptions options,
   ]);
-  external JSVoid close();
+  external void close();
   external IDBObjectStore createObjectStore(
     String name, [
     IDBObjectStoreParameters options,
   ]);
-  external JSVoid deleteObjectStore(String name);
+  external void deleteObjectStore(String name);
   external String get name;
   external int get version;
   external DOMStringList get objectStoreNames;
@@ -200,10 +200,10 @@ extension IDBObjectStoreExtension on IDBObjectStore {
   external IDBIndex index(String name);
   external IDBIndex createIndex(
     String name,
-    JSAny? keyPath, [
+    JSAny keyPath, [
     IDBIndexParameters options,
   ]);
-  external JSVoid deleteIndex(String name);
+  external void deleteIndex(String name);
   external set name(String value);
   external String get name;
   external JSAny? get keyPath;
@@ -294,10 +294,10 @@ extension IDBKeyRangeExtension on IDBKeyRange {
 class IDBCursor implements JSObject {}
 
 extension IDBCursorExtension on IDBCursor {
-  external JSVoid advance(int count);
+  external void advance(int count);
   @JS('continue')
-  external JSVoid continue_([JSAny? key]);
-  external JSVoid continuePrimaryKey(
+  external void continue_([JSAny? key]);
+  external void continuePrimaryKey(
     JSAny? key,
     JSAny? primaryKey,
   );
@@ -324,8 +324,8 @@ class IDBTransaction implements EventTarget {}
 
 extension IDBTransactionExtension on IDBTransaction {
   external IDBObjectStore objectStore(String name);
-  external JSVoid commit();
-  external JSVoid abort();
+  external void commit();
+  external void abort();
   external DOMStringList get objectStoreNames;
   external IDBTransactionMode get mode;
   external IDBTransactionDurability get durability;
diff --git a/lib/src/dom/ink_enhancement.dart b/lib/src/dom/ink_enhancement.dart
index 691e6276..d009de85 100644
--- a/lib/src/dom/ink_enhancement.dart
+++ b/lib/src/dom/ink_enhancement.dart
@@ -32,7 +32,7 @@ extension InkPresenterParamExtension on InkPresenterParam {
 class InkPresenter implements JSObject {}
 
 extension InkPresenterExtension on InkPresenter {
-  external JSVoid updateInkTrailStartPoint(
+  external void updateInkTrailStartPoint(
     PointerEvent event,
     InkTrailStyle style,
   );
diff --git a/lib/src/dom/intersection_observer.dart b/lib/src/dom/intersection_observer.dart
index ee0a531a..e16d6493 100644
--- a/lib/src/dom/intersection_observer.dart
+++ b/lib/src/dom/intersection_observer.dart
@@ -20,9 +20,9 @@ class IntersectionObserver implements JSObject {
 }
 
 extension IntersectionObserverExtension on IntersectionObserver {
-  external JSVoid observe(Element target);
-  external JSVoid unobserve(Element target);
-  external JSVoid disconnect();
+  external void observe(Element target);
+  external void unobserve(Element target);
+  external void disconnect();
   external JSArray takeRecords();
   external JSObject? get root;
   external String get rootMargin;
@@ -88,7 +88,7 @@ class IntersectionObserverInit implements JSObject {
     JSObject? root,
     String rootMargin,
     String scrollMargin,
-    JSAny? threshold,
+    JSAny threshold,
   });
 }
 
@@ -99,6 +99,6 @@ extension IntersectionObserverInitExtension on IntersectionObserverInit {
   external String get rootMargin;
   external set scrollMargin(String value);
   external String get scrollMargin;
-  external set threshold(JSAny? value);
-  external JSAny? get threshold;
+  external set threshold(JSAny value);
+  external JSAny get threshold;
 }
diff --git a/lib/src/dom/keyboard_lock.dart b/lib/src/dom/keyboard_lock.dart
index 0de94ec3..a99349fe 100644
--- a/lib/src/dom/keyboard_lock.dart
+++ b/lib/src/dom/keyboard_lock.dart
@@ -13,7 +13,7 @@ class Keyboard implements EventTarget {}
 
 extension KeyboardExtension on Keyboard {
   external JSPromise lock([JSArray keyCodes]);
-  external JSVoid unlock();
+  external void unlock();
   external JSPromise getLayoutMap();
   external set onlayoutchange(EventHandler value);
   external EventHandler get onlayoutchange;
diff --git a/lib/src/dom/media_source.dart b/lib/src/dom/media_source.dart
index 4dafd989..04234618 100644
--- a/lib/src/dom/media_source.dart
+++ b/lib/src/dom/media_source.dart
@@ -23,13 +23,13 @@ class MediaSource implements EventTarget {
 
 extension MediaSourceExtension on MediaSource {
   external SourceBuffer addSourceBuffer(String type);
-  external JSVoid removeSourceBuffer(SourceBuffer sourceBuffer);
-  external JSVoid endOfStream([EndOfStreamError error]);
-  external JSVoid setLiveSeekableRange(
+  external void removeSourceBuffer(SourceBuffer sourceBuffer);
+  external void endOfStream([EndOfStreamError error]);
+  external void setLiveSeekableRange(
     num start,
     num end,
   );
-  external JSVoid clearLiveSeekableRange();
+  external void clearLiveSeekableRange();
   external MediaSourceHandle get handle;
   external SourceBufferList get sourceBuffers;
   external SourceBufferList get activeSourceBuffers;
@@ -53,10 +53,10 @@ class MediaSourceHandle implements JSObject {}
 class SourceBuffer implements EventTarget {}
 
 extension SourceBufferExtension on SourceBuffer {
-  external JSVoid appendBuffer(BufferSource data);
-  external JSVoid abort();
-  external JSVoid changeType(String type);
-  external JSVoid remove(
+  external void appendBuffer(BufferSource data);
+  external void abort();
+  external void changeType(String type);
+  external void remove(
     num start,
     num end,
   );
diff --git a/lib/src/dom/mediacapture_fromelement.dart b/lib/src/dom/mediacapture_fromelement.dart
index 445c86d0..d62c2544 100644
--- a/lib/src/dom/mediacapture_fromelement.dart
+++ b/lib/src/dom/mediacapture_fromelement.dart
@@ -13,6 +13,6 @@ class CanvasCaptureMediaStreamTrack implements MediaStreamTrack {}
 
 extension CanvasCaptureMediaStreamTrackExtension
     on CanvasCaptureMediaStreamTrack {
-  external JSVoid requestFrame();
+  external void requestFrame();
   external HTMLCanvasElement get canvas;
 }
diff --git a/lib/src/dom/mediacapture_streams.dart b/lib/src/dom/mediacapture_streams.dart
index 6145d940..85048090 100644
--- a/lib/src/dom/mediacapture_streams.dart
+++ b/lib/src/dom/mediacapture_streams.dart
@@ -15,10 +15,10 @@ import 'permissions.dart';
 import 'screen_capture.dart';
 import 'webidl.dart';
 
-typedef ConstrainULong = JSAny?;
-typedef ConstrainDouble = JSAny?;
-typedef ConstrainBoolean = JSAny?;
-typedef ConstrainDOMString = JSAny?;
+typedef ConstrainULong = JSAny;
+typedef ConstrainDouble = JSAny;
+typedef ConstrainBoolean = JSAny;
+typedef ConstrainDOMString = JSAny;
 typedef NavigatorUserMediaSuccessCallback = JSFunction;
 typedef NavigatorUserMediaErrorCallback = JSFunction;
 typedef MediaStreamTrackState = String;
@@ -37,8 +37,8 @@ extension MediaStreamExtension on MediaStream {
   external JSArray getVideoTracks();
   external JSArray getTracks();
   external MediaStreamTrack? getTrackById(String trackId);
-  external JSVoid addTrack(MediaStreamTrack track);
-  external JSVoid removeTrack(MediaStreamTrack track);
+  external void addTrack(MediaStreamTrack track);
+  external void removeTrack(MediaStreamTrack track);
   external MediaStream clone();
   external String get id;
   external bool get active;
@@ -57,7 +57,7 @@ extension MediaStreamTrackExtension on MediaStreamTrack {
   external JSArray getSupportedCaptureActions();
   external JSPromise sendCaptureAction(CaptureAction action);
   external MediaStreamTrack clone();
-  external JSVoid stop();
+  external void stop();
   external MediaTrackCapabilities getCapabilities();
   external MediaTrackConstraints getConstraints();
   external MediaTrackSettings getSettings();
@@ -350,9 +350,9 @@ class MediaTrackConstraintSet implements JSObject {
     ConstrainDouble saturation,
     ConstrainDouble sharpness,
     ConstrainDouble focusDistance,
-    JSAny? pan,
-    JSAny? tilt,
-    JSAny? zoom,
+    JSAny pan,
+    JSAny tilt,
+    JSAny zoom,
     ConstrainBoolean torch,
     ConstrainULong width,
     ConstrainULong height,
@@ -404,12 +404,12 @@ extension MediaTrackConstraintSetExtension on MediaTrackConstraintSet {
   external ConstrainDouble get sharpness;
   external set focusDistance(ConstrainDouble value);
   external ConstrainDouble get focusDistance;
-  external set pan(JSAny? value);
-  external JSAny? get pan;
-  external set tilt(JSAny? value);
-  external JSAny? get tilt;
-  external set zoom(JSAny? value);
-  external JSAny? get zoom;
+  external set pan(JSAny value);
+  external JSAny get pan;
+  external set tilt(JSAny value);
+  external JSAny get tilt;
+  external set zoom(JSAny value);
+  external JSAny get zoom;
   external set torch(ConstrainBoolean value);
   external ConstrainBoolean get torch;
   external set width(ConstrainULong value);
@@ -620,8 +620,8 @@ class MediaDevices implements EventTarget {}
 
 extension MediaDevicesExtension on MediaDevices {
   external JSPromise selectAudioOutput([AudioOutputOptions options]);
-  external JSVoid setCaptureHandleConfig([CaptureHandleConfig config]);
-  external JSVoid setSupportedCaptureActions(JSArray actions);
+  external void setCaptureHandleConfig([CaptureHandleConfig config]);
+  external void setSupportedCaptureActions(JSArray actions);
   external JSPromise enumerateDevices();
   external MediaTrackSupportedConstraints getSupportedConstraints();
   external JSPromise getUserMedia([MediaStreamConstraints constraints]);
@@ -659,18 +659,18 @@ extension InputDeviceInfoExtension on InputDeviceInfo {
 @anonymous
 class MediaStreamConstraints implements JSObject {
   external factory MediaStreamConstraints({
-    JSAny? video,
-    JSAny? audio,
+    JSAny video,
+    JSAny audio,
     bool preferCurrentTab,
     String peerIdentity,
   });
 }
 
 extension MediaStreamConstraintsExtension on MediaStreamConstraints {
-  external set video(JSAny? value);
-  external JSAny? get video;
-  external set audio(JSAny? value);
-  external JSAny? get audio;
+  external set video(JSAny value);
+  external JSAny get video;
+  external set audio(JSAny value);
+  external JSAny get audio;
   external set preferCurrentTab(bool value);
   external bool get preferCurrentTab;
   external set peerIdentity(String value);
@@ -767,17 +767,17 @@ extension ConstrainBooleanParametersExtension on ConstrainBooleanParameters {
 @anonymous
 class ConstrainDOMStringParameters implements JSObject {
   external factory ConstrainDOMStringParameters({
-    JSAny? exact,
-    JSAny? ideal,
+    JSAny exact,
+    JSAny ideal,
   });
 }
 
 extension ConstrainDOMStringParametersExtension
     on ConstrainDOMStringParameters {
-  external set exact(JSAny? value);
-  external JSAny? get exact;
-  external set ideal(JSAny? value);
-  external JSAny? get ideal;
+  external set exact(JSAny value);
+  external JSAny get exact;
+  external set ideal(JSAny value);
+  external JSAny get ideal;
 }
 
 @JS()
diff --git a/lib/src/dom/mediacapture_viewport.dart b/lib/src/dom/mediacapture_viewport.dart
index a37165f9..bd6a9b8c 100644
--- a/lib/src/dom/mediacapture_viewport.dart
+++ b/lib/src/dom/mediacapture_viewport.dart
@@ -9,15 +9,15 @@ import 'dart:js_interop';
 @anonymous
 class ViewportMediaStreamConstraints implements JSObject {
   external factory ViewportMediaStreamConstraints({
-    JSAny? video,
-    JSAny? audio,
+    JSAny video,
+    JSAny audio,
   });
 }
 
 extension ViewportMediaStreamConstraintsExtension
     on ViewportMediaStreamConstraints {
-  external set video(JSAny? value);
-  external JSAny? get video;
-  external set audio(JSAny? value);
-  external JSAny? get audio;
+  external set video(JSAny value);
+  external JSAny get video;
+  external set audio(JSAny value);
+  external JSAny get audio;
 }
diff --git a/lib/src/dom/mediasession.dart b/lib/src/dom/mediasession.dart
index 5635e489..259316c6 100644
--- a/lib/src/dom/mediasession.dart
+++ b/lib/src/dom/mediasession.dart
@@ -13,13 +13,13 @@ typedef MediaSessionAction = String;
 class MediaSession implements JSObject {}
 
 extension MediaSessionExtension on MediaSession {
-  external JSVoid setActionHandler(
+  external void setActionHandler(
     MediaSessionAction action,
     MediaSessionActionHandler? handler,
   );
-  external JSVoid setPositionState([MediaPositionState state]);
-  external JSVoid setMicrophoneActive(bool active);
-  external JSVoid setCameraActive(bool active);
+  external void setPositionState([MediaPositionState state]);
+  external void setMicrophoneActive(bool active);
+  external void setCameraActive(bool active);
   external set metadata(MediaMetadata? value);
   external MediaMetadata? get metadata;
   external set playbackState(MediaSessionPlaybackState value);
diff --git a/lib/src/dom/mediastream_recording.dart b/lib/src/dom/mediastream_recording.dart
index c4ecf1b2..23141344 100644
--- a/lib/src/dom/mediastream_recording.dart
+++ b/lib/src/dom/mediastream_recording.dart
@@ -25,11 +25,11 @@ class MediaRecorder implements EventTarget {
 }
 
 extension MediaRecorderExtension on MediaRecorder {
-  external JSVoid start([int timeslice]);
-  external JSVoid stop();
-  external JSVoid pause();
-  external JSVoid resume();
-  external JSVoid requestData();
+  external void start([int timeslice]);
+  external void stop();
+  external void pause();
+  external void resume();
+  external void requestData();
   external MediaStream get stream;
   external String get mimeType;
   external RecordingState get state;
diff --git a/lib/src/dom/notifications.dart b/lib/src/dom/notifications.dart
index 62252dae..4a9f0fbb 100644
--- a/lib/src/dom/notifications.dart
+++ b/lib/src/dom/notifications.dart
@@ -29,7 +29,7 @@ class Notification implements EventTarget {
 }
 
 extension NotificationExtension on Notification {
-  external JSVoid close();
+  external void close();
   external set onclick(EventHandler value);
   external EventHandler get onclick;
   external set onshow(EventHandler value);
diff --git a/lib/src/dom/oes_draw_buffers_indexed.dart b/lib/src/dom/oes_draw_buffers_indexed.dart
index 4d4478b6..af49b3c2 100644
--- a/lib/src/dom/oes_draw_buffers_indexed.dart
+++ b/lib/src/dom/oes_draw_buffers_indexed.dart
@@ -11,36 +11,36 @@ import 'webgl1.dart';
 class OES_draw_buffers_indexed implements JSObject {}
 
 extension OESDrawBuffersIndexedExtension on OES_draw_buffers_indexed {
-  external JSVoid enableiOES(
+  external void enableiOES(
     GLenum target,
     GLuint index,
   );
-  external JSVoid disableiOES(
+  external void disableiOES(
     GLenum target,
     GLuint index,
   );
-  external JSVoid blendEquationiOES(
+  external void blendEquationiOES(
     GLuint buf,
     GLenum mode,
   );
-  external JSVoid blendEquationSeparateiOES(
+  external void blendEquationSeparateiOES(
     GLuint buf,
     GLenum modeRGB,
     GLenum modeAlpha,
   );
-  external JSVoid blendFunciOES(
+  external void blendFunciOES(
     GLuint buf,
     GLenum src,
     GLenum dst,
   );
-  external JSVoid blendFuncSeparateiOES(
+  external void blendFuncSeparateiOES(
     GLuint buf,
     GLenum srcRGB,
     GLenum dstRGB,
     GLenum srcAlpha,
     GLenum dstAlpha,
   );
-  external JSVoid colorMaskiOES(
+  external void colorMaskiOES(
     GLuint buf,
     GLboolean r,
     GLboolean g,
diff --git a/lib/src/dom/oes_vertex_array_object.dart b/lib/src/dom/oes_vertex_array_object.dart
index 7e0c4759..9dc8b33f 100644
--- a/lib/src/dom/oes_vertex_array_object.dart
+++ b/lib/src/dom/oes_vertex_array_object.dart
@@ -18,7 +18,7 @@ class OES_vertex_array_object implements JSObject {
 
 extension OESVertexArrayObjectExtension on OES_vertex_array_object {
   external WebGLVertexArrayObjectOES? createVertexArrayOES();
-  external JSVoid deleteVertexArrayOES(WebGLVertexArrayObjectOES? arrayObject);
+  external void deleteVertexArrayOES(WebGLVertexArrayObjectOES? arrayObject);
   external GLboolean isVertexArrayOES(WebGLVertexArrayObjectOES? arrayObject);
-  external JSVoid bindVertexArrayOES(WebGLVertexArrayObjectOES? arrayObject);
+  external void bindVertexArrayOES(WebGLVertexArrayObjectOES? arrayObject);
 }
diff --git a/lib/src/dom/orientation_sensor.dart b/lib/src/dom/orientation_sensor.dart
index 0a93b56b..6ce76903 100644
--- a/lib/src/dom/orientation_sensor.dart
+++ b/lib/src/dom/orientation_sensor.dart
@@ -14,7 +14,7 @@ typedef OrientationSensorLocalCoordinateSystem = String;
 class OrientationSensor implements Sensor {}
 
 extension OrientationSensorExtension on OrientationSensor {
-  external JSVoid populateMatrix(RotationMatrixType targetMatrix);
+  external void populateMatrix(RotationMatrixType targetMatrix);
   external JSArray? get quaternion;
 }
 
diff --git a/lib/src/dom/ovr_multiview2.dart b/lib/src/dom/ovr_multiview2.dart
index 057e89a1..f6fdfaa4 100644
--- a/lib/src/dom/ovr_multiview2.dart
+++ b/lib/src/dom/ovr_multiview2.dart
@@ -16,7 +16,7 @@ class OVR_multiview2 implements JSObject {
 }
 
 extension OVRMultiview2Extension on OVR_multiview2 {
-  external JSVoid framebufferTextureMultiviewOVR(
+  external void framebufferTextureMultiviewOVR(
     GLenum target,
     GLenum attachment,
     WebGLTexture? texture,
diff --git a/lib/src/dom/payment_handler.dart b/lib/src/dom/payment_handler.dart
index 71cc3344..a8d38b20 100644
--- a/lib/src/dom/payment_handler.dart
+++ b/lib/src/dom/payment_handler.dart
@@ -27,7 +27,7 @@ class CanMakePaymentEvent implements ExtendableEvent {
 }
 
 extension CanMakePaymentEventExtension on CanMakePaymentEvent {
-  external JSVoid respondWith(JSPromise canMakePaymentResponse);
+  external void respondWith(JSPromise canMakePaymentResponse);
 }
 
 @JS()
@@ -76,7 +76,7 @@ extension PaymentRequestEventExtension on PaymentRequestEvent {
   ]);
   external JSPromise changeShippingAddress([AddressInit shippingAddress]);
   external JSPromise changeShippingOption(String shippingOption);
-  external JSVoid respondWith(JSPromise handlerResponsePromise);
+  external void respondWith(JSPromise handlerResponsePromise);
   external String get topOrigin;
   external String get paymentRequestOrigin;
   external String get paymentRequestId;
diff --git a/lib/src/dom/payment_request.dart b/lib/src/dom/payment_request.dart
index 5e169e38..7bc5557c 100644
--- a/lib/src/dom/payment_request.dart
+++ b/lib/src/dom/payment_request.dart
@@ -244,7 +244,7 @@ class PaymentRequestUpdateEvent implements Event {
 }
 
 extension PaymentRequestUpdateEventExtension on PaymentRequestUpdateEvent {
-  external JSVoid updateWith(JSPromise detailsPromise);
+  external void updateWith(JSPromise detailsPromise);
 }
 
 @JS()
diff --git a/lib/src/dom/performance_timeline.dart b/lib/src/dom/performance_timeline.dart
index 713c18c4..c4d6b8a6 100644
--- a/lib/src/dom/performance_timeline.dart
+++ b/lib/src/dom/performance_timeline.dart
@@ -30,8 +30,8 @@ class PerformanceObserver implements JSObject {
 }
 
 extension PerformanceObserverExtension on PerformanceObserver {
-  external JSVoid observe([PerformanceObserverInit options]);
-  external JSVoid disconnect();
+  external void observe([PerformanceObserverInit options]);
+  external void disconnect();
   external PerformanceEntryList takeRecords();
 }
 
diff --git a/lib/src/dom/portals.dart b/lib/src/dom/portals.dart
index db06086d..155a3a68 100644
--- a/lib/src/dom/portals.dart
+++ b/lib/src/dom/portals.dart
@@ -15,7 +15,7 @@ class HTMLPortalElement implements HTMLElement {
 
 extension HTMLPortalElementExtension on HTMLPortalElement {
   external JSPromise activate([PortalActivateOptions options]);
-  external JSVoid postMessage(
+  external void postMessage(
     JSAny? message, [
     StructuredSerializeOptions options,
   ]);
@@ -46,7 +46,7 @@ extension PortalActivateOptionsExtension on PortalActivateOptions {
 class PortalHost implements EventTarget {}
 
 extension PortalHostExtension on PortalHost {
-  external JSVoid postMessage(
+  external void postMessage(
     JSAny? message, [
     StructuredSerializeOptions options,
   ]);
diff --git a/lib/src/dom/presentation_api.dart b/lib/src/dom/presentation_api.dart
index ac2cedf7..3d3b670d 100644
--- a/lib/src/dom/presentation_api.dart
+++ b/lib/src/dom/presentation_api.dart
@@ -24,7 +24,7 @@ extension PresentationExtension on Presentation {
 @JS('PresentationRequest')
 @staticInterop
 class PresentationRequest implements EventTarget {
-  external factory PresentationRequest(JSAny? urlOrUrls);
+  external factory PresentationRequest(JSAny urlOrUrls);
 }
 
 extension PresentationRequestExtension on PresentationRequest {
@@ -78,9 +78,9 @@ extension PresentationConnectionAvailableEventInitExtension
 class PresentationConnection implements EventTarget {}
 
 extension PresentationConnectionExtension on PresentationConnection {
-  external JSVoid close();
-  external JSVoid terminate();
-  external JSVoid send(JSAny? dataOrMessage);
+  external void close();
+  external void terminate();
+  external void send(JSAny dataOrMessage);
   external String get id;
   external String get url;
   external PresentationConnectionState get state;
diff --git a/lib/src/dom/push_api.dart b/lib/src/dom/push_api.dart
index 4f9bbea9..fc415b55 100644
--- a/lib/src/dom/push_api.dart
+++ b/lib/src/dom/push_api.dart
@@ -9,7 +9,7 @@ import 'hr_time.dart';
 import 'permissions.dart';
 import 'service_workers.dart';
 
-typedef PushMessageDataInit = JSAny?;
+typedef PushMessageDataInit = JSAny;
 typedef PushEncryptionKeyName = String;
 
 @JS()
@@ -82,7 +82,7 @@ class PushSubscriptionJSON implements JSObject {
   external factory PushSubscriptionJSON({
     String endpoint,
     EpochTimeStamp? expirationTime,
-    JSAny? keys,
+    JSAny keys,
   });
 }
 
@@ -91,8 +91,8 @@ extension PushSubscriptionJSONExtension on PushSubscriptionJSON {
   external String get endpoint;
   external set expirationTime(EpochTimeStamp? value);
   external EpochTimeStamp? get expirationTime;
-  external set keys(JSAny? value);
-  external JSAny? get keys;
+  external set keys(JSAny value);
+  external JSAny get keys;
 }
 
 @JS('PushMessageData')
diff --git a/lib/src/dom/reporting.dart b/lib/src/dom/reporting.dart
index abdaea71..76f7bf93 100644
--- a/lib/src/dom/reporting.dart
+++ b/lib/src/dom/reporting.dart
@@ -36,8 +36,8 @@ class ReportingObserver implements JSObject {
 }
 
 extension ReportingObserverExtension on ReportingObserver {
-  external JSVoid observe();
-  external JSVoid disconnect();
+  external void observe();
+  external void disconnect();
   external ReportList takeRecords();
 }
 
diff --git a/lib/src/dom/resize_observer.dart b/lib/src/dom/resize_observer.dart
index 6df25f06..a99df160 100644
--- a/lib/src/dom/resize_observer.dart
+++ b/lib/src/dom/resize_observer.dart
@@ -29,12 +29,12 @@ class ResizeObserver implements JSObject {
 }
 
 extension ResizeObserverExtension on ResizeObserver {
-  external JSVoid observe(
+  external void observe(
     Element target, [
     ResizeObserverOptions options,
   ]);
-  external JSVoid unobserve(Element target);
-  external JSVoid disconnect();
+  external void unobserve(Element target);
+  external void disconnect();
 }
 
 @JS('ResizeObserverEntry')
diff --git a/lib/src/dom/sanitizer_api.dart b/lib/src/dom/sanitizer_api.dart
index 5459b708..57244ddd 100644
--- a/lib/src/dom/sanitizer_api.dart
+++ b/lib/src/dom/sanitizer_api.dart
@@ -6,7 +6,7 @@ import 'dart:js_interop';
 
 import 'dom.dart';
 
-typedef AttributeMatchList = JSAny?;
+typedef AttributeMatchList = JSAny;
 
 @JS('Sanitizer')
 @staticInterop
diff --git a/lib/src/dom/scheduling_apis.dart b/lib/src/dom/scheduling_apis.dart
index 47359345..fed3833f 100644
--- a/lib/src/dom/scheduling_apis.dart
+++ b/lib/src/dom/scheduling_apis.dart
@@ -86,19 +86,19 @@ class TaskController implements AbortController {
 }
 
 extension TaskControllerExtension on TaskController {
-  external JSVoid setPriority(TaskPriority priority);
+  external void setPriority(TaskPriority priority);
 }
 
 @JS()
 @staticInterop
 @anonymous
 class TaskSignalAnyInit implements JSObject {
-  external factory TaskSignalAnyInit({JSAny? priority});
+  external factory TaskSignalAnyInit({JSAny priority});
 }
 
 extension TaskSignalAnyInitExtension on TaskSignalAnyInit {
-  external set priority(JSAny? value);
-  external JSAny? get priority;
+  external set priority(JSAny value);
+  external JSAny get priority;
 }
 
 @JS('TaskSignal')
diff --git a/lib/src/dom/screen_capture.dart b/lib/src/dom/screen_capture.dart
index 729d0b27..82524ea6 100644
--- a/lib/src/dom/screen_capture.dart
+++ b/lib/src/dom/screen_capture.dart
@@ -22,7 +22,7 @@ class CaptureController implements EventTarget {
 }
 
 extension CaptureControllerExtension on CaptureController {
-  external JSVoid setFocusBehavior(CaptureStartFocusBehavior focusBehavior);
+  external void setFocusBehavior(CaptureStartFocusBehavior focusBehavior);
   external set oncapturedmousechange(EventHandler value);
   external EventHandler get oncapturedmousechange;
 }
@@ -32,8 +32,8 @@ extension CaptureControllerExtension on CaptureController {
 @anonymous
 class DisplayMediaStreamOptions implements JSObject {
   external factory DisplayMediaStreamOptions({
-    JSAny? video,
-    JSAny? audio,
+    JSAny video,
+    JSAny audio,
     CaptureController controller,
     SelfCapturePreferenceEnum selfBrowserSurface,
     SystemAudioPreferenceEnum systemAudio,
@@ -43,10 +43,10 @@ class DisplayMediaStreamOptions implements JSObject {
 }
 
 extension DisplayMediaStreamOptionsExtension on DisplayMediaStreamOptions {
-  external set video(JSAny? value);
-  external JSAny? get video;
-  external set audio(JSAny? value);
-  external JSAny? get audio;
+  external set video(JSAny value);
+  external JSAny get video;
+  external set audio(JSAny value);
+  external JSAny get audio;
   external set controller(CaptureController value);
   external CaptureController get controller;
   external set selfBrowserSurface(SelfCapturePreferenceEnum value);
diff --git a/lib/src/dom/screen_orientation.dart b/lib/src/dom/screen_orientation.dart
index a884b703..b5731cbc 100644
--- a/lib/src/dom/screen_orientation.dart
+++ b/lib/src/dom/screen_orientation.dart
@@ -16,7 +16,7 @@ class ScreenOrientation implements EventTarget {}
 
 extension ScreenOrientationExtension on ScreenOrientation {
   external JSPromise lock(OrientationLockType orientation);
-  external JSVoid unlock();
+  external void unlock();
   external OrientationType get type;
   external int get angle;
   external set onchange(EventHandler value);
diff --git a/lib/src/dom/scroll_animations.dart b/lib/src/dom/scroll_animations.dart
index 777516fb..cf6405ea 100644
--- a/lib/src/dom/scroll_animations.dart
+++ b/lib/src/dom/scroll_animations.dart
@@ -45,7 +45,7 @@ class ViewTimelineOptions implements JSObject {
   external factory ViewTimelineOptions({
     Element subject,
     ScrollAxis axis,
-    JSAny? inset,
+    JSAny inset,
   });
 }
 
@@ -54,8 +54,8 @@ extension ViewTimelineOptionsExtension on ViewTimelineOptions {
   external Element get subject;
   external set axis(ScrollAxis value);
   external ScrollAxis get axis;
-  external set inset(JSAny? value);
-  external JSAny? get inset;
+  external set inset(JSAny value);
+  external JSAny get inset;
 }
 
 @JS('ViewTimeline')
diff --git a/lib/src/dom/selection_api.dart b/lib/src/dom/selection_api.dart
index 84007f07..69c0de1f 100644
--- a/lib/src/dom/selection_api.dart
+++ b/lib/src/dom/selection_api.dart
@@ -12,38 +12,38 @@ class Selection implements JSObject {}
 
 extension SelectionExtension on Selection {
   external Range getRangeAt(int index);
-  external JSVoid addRange(Range range);
-  external JSVoid removeRange(Range range);
-  external JSVoid removeAllRanges();
-  external JSVoid empty();
+  external void addRange(Range range);
+  external void removeRange(Range range);
+  external void removeAllRanges();
+  external void empty();
   external JSArray getComposedRanges(ShadowRoot shadowRoots);
-  external JSVoid collapse(
+  external void collapse(
     Node? node, [
     int offset,
   ]);
-  external JSVoid setPosition(
+  external void setPosition(
     Node? node, [
     int offset,
   ]);
-  external JSVoid collapseToStart();
-  external JSVoid collapseToEnd();
-  external JSVoid extend(
+  external void collapseToStart();
+  external void collapseToEnd();
+  external void extend(
     Node node, [
     int offset,
   ]);
-  external JSVoid setBaseAndExtent(
+  external void setBaseAndExtent(
     Node anchorNode,
     int anchorOffset,
     Node focusNode,
     int focusOffset,
   );
-  external JSVoid selectAllChildren(Node node);
-  external JSVoid modify([
+  external void selectAllChildren(Node node);
+  external void modify([
     String alter,
     String direction,
     String granularity,
   ]);
-  external JSVoid deleteFromDocument();
+  external void deleteFromDocument();
   external bool containsNode(
     Node node, [
     bool allowPartialContainment,
diff --git a/lib/src/dom/service_workers.dart b/lib/src/dom/service_workers.dart
index 649458b0..5c5707b3 100644
--- a/lib/src/dom/service_workers.dart
+++ b/lib/src/dom/service_workers.dart
@@ -27,7 +27,7 @@ typedef ClientType = String;
 class ServiceWorker implements EventTarget, AbstractWorker {}
 
 extension ServiceWorkerExtension on ServiceWorker {
-  external JSVoid postMessage(
+  external void postMessage(
     JSAny? message, [
     JSObject optionsOrTransfer,
   ]);
@@ -77,7 +77,7 @@ extension ServiceWorkerContainerExtension on ServiceWorkerContainer {
   ]);
   external JSPromise getRegistration([String clientURL]);
   external JSPromise getRegistrations();
-  external JSVoid startMessages();
+  external void startMessages();
   external ServiceWorker? get controller;
   external JSPromise get ready;
   external set oncontrollerchange(EventHandler value);
@@ -191,7 +191,7 @@ extension ServiceWorkerGlobalScopeExtension on ServiceWorkerGlobalScope {
 class Client implements JSObject {}
 
 extension ClientExtension on Client {
-  external JSVoid postMessage(
+  external void postMessage(
     JSAny? message, [
     JSObject optionsOrTransfer,
   ]);
@@ -252,7 +252,7 @@ class ExtendableEvent implements Event {
 }
 
 extension ExtendableEventExtension on ExtendableEvent {
-  external JSVoid waitUntil(JSPromise f);
+  external void waitUntil(JSPromise f);
 }
 
 @JS()
@@ -272,7 +272,7 @@ class FetchEvent implements ExtendableEvent {
 }
 
 extension FetchEventExtension on FetchEvent {
-  external JSVoid respondWith(JSPromise r);
+  external void respondWith(JSPromise r);
   external Request get request;
   external JSPromise get preloadResponse;
   external String get clientId;
diff --git a/lib/src/dom/shared_storage.dart b/lib/src/dom/shared_storage.dart
index deb4b57a..2a90aff9 100644
--- a/lib/src/dom/shared_storage.dart
+++ b/lib/src/dom/shared_storage.dart
@@ -6,7 +6,7 @@ import 'dart:js_interop';
 
 import 'html.dart';
 
-typedef SharedStorageResponse = JSAny?;
+typedef SharedStorageResponse = JSAny;
 typedef SharedStorageOperationConstructor = JSFunction;
 
 @JS('SharedStorageWorklet')
@@ -19,7 +19,7 @@ class SharedStorageWorkletGlobalScope implements WorkletGlobalScope {}
 
 extension SharedStorageWorkletGlobalScopeExtension
     on SharedStorageWorkletGlobalScope {
-  external JSVoid register(
+  external void register(
     String name,
     SharedStorageOperationConstructor operationCtor,
   );
diff --git a/lib/src/dom/speech_api.dart b/lib/src/dom/speech_api.dart
index 46f93803..0c818782 100644
--- a/lib/src/dom/speech_api.dart
+++ b/lib/src/dom/speech_api.dart
@@ -17,9 +17,9 @@ class SpeechRecognition implements EventTarget {
 }
 
 extension SpeechRecognitionExtension on SpeechRecognition {
-  external JSVoid start();
-  external JSVoid stop();
-  external JSVoid abort();
+  external void start();
+  external void stop();
+  external void abort();
   external set grammars(SpeechGrammarList value);
   external SpeechGrammarList get grammars;
   external set lang(String value);
@@ -165,11 +165,11 @@ class SpeechGrammarList implements JSObject {
 
 extension SpeechGrammarListExtension on SpeechGrammarList {
   external SpeechGrammar item(int index);
-  external JSVoid addFromURI(
+  external void addFromURI(
     String src, [
     num weight,
   ]);
-  external JSVoid addFromString(
+  external void addFromString(
     String string, [
     num weight,
   ]);
@@ -181,10 +181,10 @@ extension SpeechGrammarListExtension on SpeechGrammarList {
 class SpeechSynthesis implements EventTarget {}
 
 extension SpeechSynthesisExtension on SpeechSynthesis {
-  external JSVoid speak(SpeechSynthesisUtterance utterance);
-  external JSVoid cancel();
-  external JSVoid pause();
-  external JSVoid resume();
+  external void speak(SpeechSynthesisUtterance utterance);
+  external void cancel();
+  external void pause();
+  external void resume();
   external JSArray getVoices();
   external bool get pending;
   external bool get speaking;
diff --git a/lib/src/dom/streams.dart b/lib/src/dom/streams.dart
index 43c99e52..005509af 100644
--- a/lib/src/dom/streams.dart
+++ b/lib/src/dom/streams.dart
@@ -161,7 +161,7 @@ class ReadableStreamDefaultReader implements ReadableStreamGenericReader {
 
 extension ReadableStreamDefaultReaderExtension on ReadableStreamDefaultReader {
   external JSPromise read();
-  external JSVoid releaseLock();
+  external void releaseLock();
 }
 
 @JS()
@@ -189,7 +189,7 @@ class ReadableStreamBYOBReader implements ReadableStreamGenericReader {
 
 extension ReadableStreamBYOBReaderExtension on ReadableStreamBYOBReader {
   external JSPromise read(ArrayBufferView view);
-  external JSVoid releaseLock();
+  external void releaseLock();
 }
 
 @JS('ReadableStreamDefaultController')
@@ -198,9 +198,9 @@ class ReadableStreamDefaultController implements JSObject {}
 
 extension ReadableStreamDefaultControllerExtension
     on ReadableStreamDefaultController {
-  external JSVoid close();
-  external JSVoid enqueue([JSAny? chunk]);
-  external JSVoid error([JSAny? e]);
+  external void close();
+  external void enqueue([JSAny? chunk]);
+  external void error([JSAny? e]);
   external num? get desiredSize;
 }
 
@@ -210,9 +210,9 @@ class ReadableByteStreamController implements JSObject {}
 
 extension ReadableByteStreamControllerExtension
     on ReadableByteStreamController {
-  external JSVoid close();
-  external JSVoid enqueue(ArrayBufferView chunk);
-  external JSVoid error([JSAny? e]);
+  external void close();
+  external void enqueue(ArrayBufferView chunk);
+  external void error([JSAny? e]);
   external ReadableStreamBYOBRequest? get byobRequest;
   external num? get desiredSize;
 }
@@ -222,8 +222,8 @@ extension ReadableByteStreamControllerExtension
 class ReadableStreamBYOBRequest implements JSObject {}
 
 extension ReadableStreamBYOBRequestExtension on ReadableStreamBYOBRequest {
-  external JSVoid respond(int bytesWritten);
-  external JSVoid respondWithNewView(ArrayBufferView view);
+  external void respond(int bytesWritten);
+  external void respondWithNewView(ArrayBufferView view);
   external ArrayBufferView? get view;
 }
 
@@ -278,7 +278,7 @@ class WritableStreamDefaultWriter implements JSObject {
 extension WritableStreamDefaultWriterExtension on WritableStreamDefaultWriter {
   external JSPromise abort([JSAny? reason]);
   external JSPromise close();
-  external JSVoid releaseLock();
+  external void releaseLock();
   external JSPromise write([JSAny? chunk]);
   external JSPromise get closed;
   external num? get desiredSize;
@@ -291,7 +291,7 @@ class WritableStreamDefaultController implements JSObject {}
 
 extension WritableStreamDefaultControllerExtension
     on WritableStreamDefaultController {
-  external JSVoid error([JSAny? e]);
+  external void error([JSAny? e]);
   external AbortSignal get signal;
 }
 
@@ -345,9 +345,9 @@ class TransformStreamDefaultController implements JSObject {}
 
 extension TransformStreamDefaultControllerExtension
     on TransformStreamDefaultController {
-  external JSVoid enqueue([JSAny? chunk]);
-  external JSVoid error([JSAny? reason]);
-  external JSVoid terminate();
+  external void enqueue([JSAny? chunk]);
+  external void error([JSAny? reason]);
+  external void terminate();
   external num? get desiredSize;
 }
 
diff --git a/lib/src/dom/svg.dart b/lib/src/dom/svg.dart
index b6faef77..9ce68301 100644
--- a/lib/src/dom/svg.dart
+++ b/lib/src/dom/svg.dart
@@ -98,11 +98,11 @@ class SVGLength implements JSObject {
 }
 
 extension SVGLengthExtension on SVGLength {
-  external JSVoid newValueSpecifiedUnits(
+  external void newValueSpecifiedUnits(
     int unitType,
     num valueInSpecifiedUnits,
   );
-  external JSVoid convertToSpecifiedUnits(int unitType);
+  external void convertToSpecifiedUnits(int unitType);
   external int get unitType;
   external set value(num value);
   external num get value;
@@ -123,11 +123,11 @@ class SVGAngle implements JSObject {
 }
 
 extension SVGAngleExtension on SVGAngle {
-  external JSVoid newValueSpecifiedUnits(
+  external void newValueSpecifiedUnits(
     int unitType,
     num valueInSpecifiedUnits,
   );
-  external JSVoid convertToSpecifiedUnits(int unitType);
+  external void convertToSpecifiedUnits(int unitType);
   external int get unitType;
   external set value(num value);
   external num get value;
@@ -142,7 +142,7 @@ extension SVGAngleExtension on SVGAngle {
 class SVGNumberList implements JSObject {}
 
 extension SVGNumberListExtension on SVGNumberList {
-  external JSVoid clear();
+  external void clear();
   external SVGNumber initialize(SVGNumber newItem);
   external SVGNumber getItem(int index);
   external SVGNumber insertItemBefore(
@@ -164,7 +164,7 @@ extension SVGNumberListExtension on SVGNumberList {
 class SVGLengthList implements JSObject {}
 
 extension SVGLengthListExtension on SVGLengthList {
-  external JSVoid clear();
+  external void clear();
   external SVGLength initialize(SVGLength newItem);
   external SVGLength getItem(int index);
   external SVGLength insertItemBefore(
@@ -186,7 +186,7 @@ extension SVGLengthListExtension on SVGLengthList {
 class SVGStringList implements JSObject {}
 
 extension SVGStringListExtension on SVGStringList {
-  external JSVoid clear();
+  external void clear();
   external String initialize(String newItem);
   external String getItem(int index);
   external String insertItemBefore(
@@ -354,7 +354,7 @@ extension SVGSVGElementExtension on SVGSVGElement {
     SVGElement element,
     DOMRectReadOnly rect,
   );
-  external JSVoid deselectAll();
+  external void deselectAll();
   external SVGNumber createSVGNumber();
   external SVGLength createSVGLength();
   external SVGAngle createSVGAngle();
@@ -365,14 +365,14 @@ extension SVGSVGElementExtension on SVGSVGElement {
   external SVGTransform createSVGTransformFromMatrix([DOMMatrix2DInit matrix]);
   external Element getElementById(String elementId);
   external int suspendRedraw(int maxWaitMilliseconds);
-  external JSVoid unsuspendRedraw(int suspendHandleID);
-  external JSVoid unsuspendRedrawAll();
-  external JSVoid forceRedraw();
-  external JSVoid pauseAnimations();
-  external JSVoid unpauseAnimations();
+  external void unsuspendRedraw(int suspendHandleID);
+  external void unsuspendRedrawAll();
+  external void forceRedraw();
+  external void pauseAnimations();
+  external void unpauseAnimations();
   external bool animationsPaused();
   external num getCurrentTime();
-  external JSVoid setCurrentTime(num seconds);
+  external void setCurrentTime(num seconds);
   external SVGAnimatedLength get x;
   external SVGAnimatedLength get y;
   external SVGAnimatedLength get width;
@@ -483,22 +483,22 @@ class SVGTransform implements JSObject {
 }
 
 extension SVGTransformExtension on SVGTransform {
-  external JSVoid setMatrix([DOMMatrix2DInit matrix]);
-  external JSVoid setTranslate(
+  external void setMatrix([DOMMatrix2DInit matrix]);
+  external void setTranslate(
     num tx,
     num ty,
   );
-  external JSVoid setScale(
+  external void setScale(
     num sx,
     num sy,
   );
-  external JSVoid setRotate(
+  external void setRotate(
     num angle,
     num cx,
     num cy,
   );
-  external JSVoid setSkewX(num angle);
-  external JSVoid setSkewY(num angle);
+  external void setSkewX(num angle);
+  external void setSkewY(num angle);
   external int get type;
   external DOMMatrix get matrix;
   external num get angle;
@@ -509,7 +509,7 @@ extension SVGTransformExtension on SVGTransform {
 class SVGTransformList implements JSObject {}
 
 extension SVGTransformListExtension on SVGTransformList {
-  external JSVoid clear();
+  external void clear();
   external SVGTransform initialize(SVGTransform newItem);
   external SVGTransform getItem(int index);
   external SVGTransform insertItemBefore(
@@ -636,7 +636,7 @@ extension SVGAnimatedPointsExtension on SVGAnimatedPoints {
 class SVGPointList implements JSObject {}
 
 extension SVGPointListExtension on SVGPointList {
-  external JSVoid clear();
+  external void clear();
   external DOMPoint initialize(DOMPoint newItem);
   external DOMPoint getItem(int index);
   external DOMPoint insertItemBefore(
@@ -681,7 +681,7 @@ extension SVGTextContentElementExtension on SVGTextContentElement {
   external DOMRect getExtentOfChar(int charnum);
   external num getRotationOfChar(int charnum);
   external int getCharNumAtPosition([DOMPointInit point]);
-  external JSVoid selectSubString(
+  external void selectSubString(
     int charnum,
     int nchars,
   );
@@ -763,8 +763,8 @@ class SVGMarkerElement implements SVGElement, SVGFitToViewBox {
 }
 
 extension SVGMarkerElementExtension on SVGMarkerElement {
-  external JSVoid setOrientToAuto();
-  external JSVoid setOrientToAngle(SVGAngle angle);
+  external void setOrientToAuto();
+  external void setOrientToAngle(SVGAngle angle);
   external SVGAnimatedLength get refX;
   external SVGAnimatedLength get refY;
   external SVGAnimatedEnumeration get markerUnits;
diff --git a/lib/src/dom/svg_animations.dart b/lib/src/dom/svg_animations.dart
index 0d923f6e..acf3da1e 100644
--- a/lib/src/dom/svg_animations.dart
+++ b/lib/src/dom/svg_animations.dart
@@ -13,7 +13,7 @@ import 'svg.dart';
 class TimeEvent implements Event {}
 
 extension TimeEventExtension on TimeEvent {
-  external JSVoid initTimeEvent(
+  external void initTimeEvent(
     String typeArg,
     Window? viewArg,
     int detailArg,
@@ -30,10 +30,10 @@ extension SVGAnimationElementExtension on SVGAnimationElement {
   external num getStartTime();
   external num getCurrentTime();
   external num getSimpleDuration();
-  external JSVoid beginElement();
-  external JSVoid beginElementAt(num offset);
-  external JSVoid endElement();
-  external JSVoid endElementAt(num offset);
+  external void beginElement();
+  external void beginElementAt(num offset);
+  external void endElement();
+  external void endElementAt(num offset);
   external SVGElement? get targetElement;
   external set onbegin(EventHandler value);
   external EventHandler get onbegin;
diff --git a/lib/src/dom/turtledove.dart b/lib/src/dom/turtledove.dart
index 3a87b486..b1051660 100644
--- a/lib/src/dom/turtledove.dart
+++ b/lib/src/dom/turtledove.dart
@@ -41,7 +41,7 @@ class GenerateBidInterestGroup implements JSObject {
     required String name,
     required num lifetimeMs,
     bool enableBiddingSignalsPrioritization,
-    JSAny? priorityVector,
+    JSAny priorityVector,
     String executionMode,
     String biddingLogicURL,
     String biddingWasmHelperURL,
@@ -63,8 +63,8 @@ extension GenerateBidInterestGroupExtension on GenerateBidInterestGroup {
   external num get lifetimeMs;
   external set enableBiddingSignalsPrioritization(bool value);
   external bool get enableBiddingSignalsPrioritization;
-  external set priorityVector(JSAny? value);
-  external JSAny? get priorityVector;
+  external set priorityVector(JSAny value);
+  external JSAny get priorityVector;
   external set executionMode(String value);
   external String get executionMode;
   external set biddingLogicURL(String value);
@@ -91,15 +91,15 @@ extension GenerateBidInterestGroupExtension on GenerateBidInterestGroup {
 class AuctionAdInterestGroup implements GenerateBidInterestGroup {
   external factory AuctionAdInterestGroup({
     num priority,
-    JSAny? prioritySignalsOverrides,
+    JSAny prioritySignalsOverrides,
   });
 }
 
 extension AuctionAdInterestGroupExtension on AuctionAdInterestGroup {
   external set priority(num value);
   external num get priority;
-  external set prioritySignalsOverrides(JSAny? value);
-  external JSAny? get prioritySignalsOverrides;
+  external set prioritySignalsOverrides(JSAny value);
+  external JSAny get prioritySignalsOverrides;
 }
 
 @JS()
@@ -136,9 +136,9 @@ class AuctionAdConfig implements JSObject {
     String sellerCurrency,
     JSPromise perBuyerSignals,
     JSPromise perBuyerTimeouts,
-    JSAny? perBuyerGroupLimits,
-    JSAny? perBuyerExperimentGroupIds,
-    JSAny? perBuyerPrioritySignals,
+    JSAny perBuyerGroupLimits,
+    JSAny perBuyerExperimentGroupIds,
+    JSAny perBuyerPrioritySignals,
     JSPromise perBuyerCurrencies,
     JSArray componentAuctions,
     AbortSignal? signal,
@@ -171,12 +171,12 @@ extension AuctionAdConfigExtension on AuctionAdConfig {
   external JSPromise get perBuyerSignals;
   external set perBuyerTimeouts(JSPromise value);
   external JSPromise get perBuyerTimeouts;
-  external set perBuyerGroupLimits(JSAny? value);
-  external JSAny? get perBuyerGroupLimits;
-  external set perBuyerExperimentGroupIds(JSAny? value);
-  external JSAny? get perBuyerExperimentGroupIds;
-  external set perBuyerPrioritySignals(JSAny? value);
-  external JSAny? get perBuyerPrioritySignals;
+  external set perBuyerGroupLimits(JSAny value);
+  external JSAny get perBuyerGroupLimits;
+  external set perBuyerExperimentGroupIds(JSAny value);
+  external JSAny get perBuyerExperimentGroupIds;
+  external set perBuyerPrioritySignals(JSAny value);
+  external JSAny get perBuyerPrioritySignals;
   external set perBuyerCurrencies(JSPromise value);
   external JSPromise get perBuyerCurrencies;
   external set componentAuctions(JSArray value);
@@ -199,8 +199,8 @@ class InterestGroupBiddingScriptRunnerGlobalScope
 extension InterestGroupBiddingScriptRunnerGlobalScopeExtension
     on InterestGroupBiddingScriptRunnerGlobalScope {
   external bool setBid([GenerateBidOutput generateBidOutput]);
-  external JSVoid setPriority(num priority);
-  external JSVoid setPrioritySignalsOverride(
+  external void setPriority(num priority);
+  external void setPrioritySignalsOverride(
     String key, [
     num? priority,
   ]);
@@ -233,7 +233,7 @@ class GenerateBidOutput implements JSObject {
   external factory GenerateBidOutput({
     num bid,
     String bidCurrency,
-    JSAny? render,
+    JSAny render,
     JSAny? ad,
     JSArray adComponents,
     num adCost,
@@ -247,8 +247,8 @@ extension GenerateBidOutputExtension on GenerateBidOutput {
   external num get bid;
   external set bidCurrency(String value);
   external String get bidCurrency;
-  external set render(JSAny? value);
-  external JSAny? get render;
+  external set render(JSAny value);
+  external JSAny get render;
   external set ad(JSAny? value);
   external JSAny? get ad;
   external set adComponents(JSArray value);
@@ -273,9 +273,9 @@ class InterestGroupReportingScriptRunnerGlobalScope
 
 extension InterestGroupReportingScriptRunnerGlobalScopeExtension
     on InterestGroupReportingScriptRunnerGlobalScope {
-  external JSVoid sendReportTo(String url);
-  external JSVoid registerAdBeacon(JSAny? map);
-  external JSVoid registerAdMacro(
+  external void sendReportTo(String url);
+  external void registerAdBeacon(JSAny map);
+  external void registerAdMacro(
     String name,
     String value,
   );
diff --git a/lib/src/dom/uievents.dart b/lib/src/dom/uievents.dart
index cd40d8cb..869c681c 100644
--- a/lib/src/dom/uievents.dart
+++ b/lib/src/dom/uievents.dart
@@ -18,7 +18,7 @@ class UIEvent implements Event {
 }
 
 extension UIEventExtension on UIEvent {
-  external JSVoid initUIEvent(
+  external void initUIEvent(
     String typeArg, [
     bool bubblesArg,
     bool cancelableArg,
@@ -90,7 +90,7 @@ class MouseEvent implements UIEvent {
 
 extension MouseEventExtension on MouseEvent {
   external bool getModifierState(String keyArg);
-  external JSVoid initMouseEvent(
+  external void initMouseEvent(
     String typeArg, [
     bool bubblesArg,
     bool cancelableArg,
@@ -323,7 +323,7 @@ class KeyboardEvent implements UIEvent {
 
 extension KeyboardEventExtension on KeyboardEvent {
   external bool getModifierState(String keyArg);
-  external JSVoid initKeyboardEvent(
+  external void initKeyboardEvent(
     String typeArg, [
     bool bubblesArg,
     bool cancelableArg,
@@ -390,7 +390,7 @@ class CompositionEvent implements UIEvent {
 }
 
 extension CompositionEventExtension on CompositionEvent {
-  external JSVoid initCompositionEvent(
+  external void initCompositionEvent(
     String typeArg, [
     bool bubblesArg,
     bool cancelableArg,
@@ -421,7 +421,7 @@ class MutationEvent implements Event {
 }
 
 extension MutationEventExtension on MutationEvent {
-  external JSVoid initMutationEvent(
+  external void initMutationEvent(
     String typeArg, [
     bool bubblesArg,
     bool cancelableArg,
diff --git a/lib/src/dom/url.dart b/lib/src/dom/url.dart
index 21b4e108..50da0f08 100644
--- a/lib/src/dom/url.dart
+++ b/lib/src/dom/url.dart
@@ -13,7 +13,7 @@ class URL implements JSObject {
   ]);
 
   external static String createObjectURL(JSObject obj);
-  external static JSVoid revokeObjectURL(String url);
+  external static void revokeObjectURL(String url);
   external static bool canParse(
     String url, [
     String base,
@@ -49,15 +49,15 @@ extension URLExtension on URL {
 @JS('URLSearchParams')
 @staticInterop
 class URLSearchParams implements JSObject {
-  external factory URLSearchParams([JSAny? init]);
+  external factory URLSearchParams([JSAny init]);
 }
 
 extension URLSearchParamsExtension on URLSearchParams {
-  external JSVoid append(
+  external void append(
     String name,
     String value,
   );
-  external JSVoid delete(
+  external void delete(
     String name, [
     String value,
   ]);
@@ -67,10 +67,10 @@ extension URLSearchParamsExtension on URLSearchParams {
     String name, [
     String value,
   ]);
-  external JSVoid set(
+  external void set(
     String name,
     String value,
   );
-  external JSVoid sort();
+  external void sort();
   external int get size;
 }
diff --git a/lib/src/dom/urlpattern.dart b/lib/src/dom/urlpattern.dart
index e7f3f653..3f556beb 100644
--- a/lib/src/dom/urlpattern.dart
+++ b/lib/src/dom/urlpattern.dart
@@ -4,14 +4,14 @@
 
 import 'dart:js_interop';
 
-typedef URLPatternInput = JSAny?;
+typedef URLPatternInput = JSAny;
 
 @JS('URLPattern')
 @staticInterop
 class URLPattern implements JSObject {
   external factory URLPattern([
     URLPatternInput input,
-    JSAny? baseURLOrOptions,
+    JSAny baseURLOrOptions,
     URLPatternOptions options,
   ]);
 }
@@ -129,13 +129,13 @@ extension URLPatternResultExtension on URLPatternResult {
 class URLPatternComponentResult implements JSObject {
   external factory URLPatternComponentResult({
     String input,
-    JSAny? groups,
+    JSAny groups,
   });
 }
 
 extension URLPatternComponentResultExtension on URLPatternComponentResult {
   external set input(String value);
   external String get input;
-  external set groups(JSAny? value);
-  external JSAny? get groups;
+  external set groups(JSAny value);
+  external JSAny get groups;
 }
diff --git a/lib/src/dom/user_timing.dart b/lib/src/dom/user_timing.dart
index 9973d405..9fa9eb19 100644
--- a/lib/src/dom/user_timing.dart
+++ b/lib/src/dom/user_timing.dart
@@ -30,21 +30,21 @@ extension PerformanceMarkOptionsExtension on PerformanceMarkOptions {
 class PerformanceMeasureOptions implements JSObject {
   external factory PerformanceMeasureOptions({
     JSAny? detail,
-    JSAny? start,
+    JSAny start,
     DOMHighResTimeStamp duration,
-    JSAny? end,
+    JSAny end,
   });
 }
 
 extension PerformanceMeasureOptionsExtension on PerformanceMeasureOptions {
   external set detail(JSAny? value);
   external JSAny? get detail;
-  external set start(JSAny? value);
-  external JSAny? get start;
+  external set start(JSAny value);
+  external JSAny get start;
   external set duration(DOMHighResTimeStamp value);
   external DOMHighResTimeStamp get duration;
-  external set end(JSAny? value);
-  external JSAny? get end;
+  external set end(JSAny value);
+  external JSAny get end;
 }
 
 @JS('PerformanceMark')
diff --git a/lib/src/dom/vibration.dart b/lib/src/dom/vibration.dart
index 57c7671e..42121175 100644
--- a/lib/src/dom/vibration.dart
+++ b/lib/src/dom/vibration.dart
@@ -4,4 +4,4 @@
 
 import 'dart:js_interop';
 
-typedef VibratePattern = JSAny?;
+typedef VibratePattern = JSAny;
diff --git a/lib/src/dom/virtual_keyboard.dart b/lib/src/dom/virtual_keyboard.dart
index 9bfa3f10..6d5cf09e 100644
--- a/lib/src/dom/virtual_keyboard.dart
+++ b/lib/src/dom/virtual_keyboard.dart
@@ -13,8 +13,8 @@ import 'html.dart';
 class VirtualKeyboard implements EventTarget {}
 
 extension VirtualKeyboardExtension on VirtualKeyboard {
-  external JSVoid show();
-  external JSVoid hide();
+  external void show();
+  external void hide();
   external DOMRect get boundingRect;
   external set overlaysContent(bool value);
   external bool get overlaysContent;
diff --git a/lib/src/dom/wasm_js_api.dart b/lib/src/dom/wasm_js_api.dart
index 69b57c3a..4bdb3051 100644
--- a/lib/src/dom/wasm_js_api.dart
+++ b/lib/src/dom/wasm_js_api.dart
@@ -175,7 +175,7 @@ extension TableExtension on Table {
     JSAny? value,
   ]);
   external JSAny? get(int index);
-  external JSVoid set(
+  external void set(
     int index, [
     JSAny? value,
   ]);
diff --git a/lib/src/dom/web_animations.dart b/lib/src/dom/web_animations.dart
index 0a0398c1..ce7959ee 100644
--- a/lib/src/dom/web_animations.dart
+++ b/lib/src/dom/web_animations.dart
@@ -55,14 +55,14 @@ class Animation implements EventTarget {
 }
 
 extension AnimationExtension on Animation {
-  external JSVoid cancel();
-  external JSVoid finish();
-  external JSVoid play();
-  external JSVoid pause();
-  external JSVoid updatePlaybackRate(num playbackRate);
-  external JSVoid reverse();
-  external JSVoid persist();
-  external JSVoid commitStyles();
+  external void cancel();
+  external void finish();
+  external void play();
+  external void pause();
+  external void updatePlaybackRate(num playbackRate);
+  external void reverse();
+  external void persist();
+  external void commitStyles();
   external set startTime(CSSNumberish? value);
   external CSSNumberish? get startTime;
   external set currentTime(CSSNumberish? value);
@@ -93,13 +93,13 @@ extension AnimationExtension on Animation {
 class AnimationEffect implements JSObject {}
 
 extension AnimationEffectExtension on AnimationEffect {
-  external JSVoid before(AnimationEffect effects);
-  external JSVoid after(AnimationEffect effects);
-  external JSVoid replace(AnimationEffect effects);
-  external JSVoid remove();
+  external void before(AnimationEffect effects);
+  external void after(AnimationEffect effects);
+  external void replace(AnimationEffect effects);
+  external void remove();
   external EffectTiming getTiming();
   external ComputedEffectTiming getComputedTiming();
-  external JSVoid updateTiming([OptionalEffectTiming timing]);
+  external void updateTiming([OptionalEffectTiming timing]);
   external GroupEffect? get parent;
   external AnimationEffect? get previousSibling;
   external AnimationEffect? get nextSibling;
@@ -113,7 +113,7 @@ class EffectTiming implements JSObject {
     num delay,
     num endDelay,
     num playbackRate,
-    JSAny? duration,
+    JSAny duration,
     FillMode fill,
     num iterationStart,
     num iterations,
@@ -129,8 +129,8 @@ extension EffectTimingExtension on EffectTiming {
   external num get endDelay;
   external set playbackRate(num value);
   external num get playbackRate;
-  external set duration(JSAny? value);
-  external JSAny? get duration;
+  external set duration(JSAny value);
+  external JSAny get duration;
   external set fill(FillMode value);
   external FillMode get fill;
   external set iterationStart(num value);
@@ -154,7 +154,7 @@ class OptionalEffectTiming implements JSObject {
     FillMode fill,
     num iterationStart,
     num iterations,
-    JSAny? duration,
+    JSAny duration,
     PlaybackDirection direction,
     String easing,
   });
@@ -173,8 +173,8 @@ extension OptionalEffectTimingExtension on OptionalEffectTiming {
   external num get iterationStart;
   external set iterations(num value);
   external num get iterations;
-  external set duration(JSAny? value);
-  external JSAny? get duration;
+  external set duration(JSAny value);
+  external JSAny get duration;
   external set direction(PlaybackDirection value);
   external PlaybackDirection get direction;
   external set easing(String value);
@@ -216,13 +216,13 @@ class KeyframeEffect implements AnimationEffect {
   external factory KeyframeEffect(
     JSObject? sourceOrTarget, [
     JSObject? keyframes,
-    JSAny? options,
+    JSAny options,
   ]);
 }
 
 extension KeyframeEffectExtension on KeyframeEffect {
   external JSArray getKeyframes();
-  external JSVoid setKeyframes(JSObject? keyframes);
+  external void setKeyframes(JSObject? keyframes);
   external set iterationComposite(IterationCompositeOperation value);
   external IterationCompositeOperation get iterationComposite;
   external set target(Element? value);
@@ -262,18 +262,18 @@ extension BaseComputedKeyframeExtension on BaseComputedKeyframe {
 class BasePropertyIndexedKeyframe implements JSObject {
   external factory BasePropertyIndexedKeyframe({
     JSAny? offset,
-    JSAny? easing,
-    JSAny? composite,
+    JSAny easing,
+    JSAny composite,
   });
 }
 
 extension BasePropertyIndexedKeyframeExtension on BasePropertyIndexedKeyframe {
   external set offset(JSAny? value);
   external JSAny? get offset;
-  external set easing(JSAny? value);
-  external JSAny? get easing;
-  external set composite(JSAny? value);
-  external JSAny? get composite;
+  external set easing(JSAny value);
+  external JSAny get easing;
+  external set composite(JSAny value);
+  external JSAny get composite;
 }
 
 @JS()
@@ -323,7 +323,7 @@ class Animatable implements JSObject {}
 extension AnimatableExtension on Animatable {
   external Animation animate(
     JSObject? keyframes, [
-    JSAny? options,
+    JSAny options,
   ]);
   external JSArray getAnimations([GetAnimationsOptions options]);
 }
@@ -333,18 +333,18 @@ extension AnimatableExtension on Animatable {
 @anonymous
 class KeyframeAnimationOptions implements KeyframeEffectOptions {
   external factory KeyframeAnimationOptions({
-    JSAny? rangeStart,
-    JSAny? rangeEnd,
+    JSAny rangeStart,
+    JSAny rangeEnd,
     String id,
     AnimationTimeline? timeline,
   });
 }
 
 extension KeyframeAnimationOptionsExtension on KeyframeAnimationOptions {
-  external set rangeStart(JSAny? value);
-  external JSAny? get rangeStart;
-  external set rangeEnd(JSAny? value);
-  external JSAny? get rangeEnd;
+  external set rangeStart(JSAny value);
+  external JSAny get rangeStart;
+  external set rangeEnd(JSAny value);
+  external JSAny get rangeEnd;
   external set id(String value);
   external String get id;
   external set timeline(AnimationTimeline? value);
diff --git a/lib/src/dom/web_animations_2.dart b/lib/src/dom/web_animations_2.dart
index f1c5c626..a3a04bce 100644
--- a/lib/src/dom/web_animations_2.dart
+++ b/lib/src/dom/web_animations_2.dart
@@ -16,14 +16,14 @@ typedef IterationCompositeOperation = String;
 class GroupEffect implements JSObject {
   external factory GroupEffect(
     JSArray? children, [
-    JSAny? timing,
+    JSAny timing,
   ]);
 }
 
 extension GroupEffectExtension on GroupEffect {
   external GroupEffect clone();
-  external JSVoid prepend(AnimationEffect effects);
-  external JSVoid append(AnimationEffect effects);
+  external void prepend(AnimationEffect effects);
+  external void append(AnimationEffect effects);
   external AnimationNodeList get children;
   external AnimationEffect? get firstChild;
   external AnimationEffect? get lastChild;
@@ -43,7 +43,7 @@ extension AnimationNodeListExtension on AnimationNodeList {
 class SequenceEffect implements GroupEffect {
   external factory SequenceEffect(
     JSArray? children, [
-    JSAny? timing,
+    JSAny timing,
   ]);
 }
 
diff --git a/lib/src/dom/web_app_launch.dart b/lib/src/dom/web_app_launch.dart
index d43f5183..54f01fd9 100644
--- a/lib/src/dom/web_app_launch.dart
+++ b/lib/src/dom/web_app_launch.dart
@@ -20,5 +20,5 @@ extension LaunchParamsExtension on LaunchParams {
 class LaunchQueue implements JSObject {}
 
 extension LaunchQueueExtension on LaunchQueue {
-  external JSVoid setConsumer(LaunchConsumer consumer);
+  external void setConsumer(LaunchConsumer consumer);
 }
diff --git a/lib/src/dom/web_bluetooth.dart b/lib/src/dom/web_bluetooth.dart
index 2533b11d..c5b1deb2 100644
--- a/lib/src/dom/web_bluetooth.dart
+++ b/lib/src/dom/web_bluetooth.dart
@@ -10,9 +10,9 @@ import 'permissions.dart';
 import 'webidl.dart';
 
 typedef UUID = String;
-typedef BluetoothServiceUUID = JSAny?;
-typedef BluetoothCharacteristicUUID = JSAny?;
-typedef BluetoothDescriptorUUID = JSAny?;
+typedef BluetoothServiceUUID = JSAny;
+typedef BluetoothCharacteristicUUID = JSAny;
+typedef BluetoothDescriptorUUID = JSAny;
 
 @JS()
 @staticInterop
@@ -163,7 +163,7 @@ class AllowedBluetoothDevice implements JSObject {
   external factory AllowedBluetoothDevice({
     required String deviceId,
     required bool mayUseGATT,
-    required JSAny? allowedServices,
+    required JSAny allowedServices,
     required JSArray allowedManufacturerData,
   });
 }
@@ -173,8 +173,8 @@ extension AllowedBluetoothDeviceExtension on AllowedBluetoothDevice {
   external String get deviceId;
   external set mayUseGATT(bool value);
   external bool get mayUseGATT;
-  external set allowedServices(JSAny? value);
-  external JSAny? get allowedServices;
+  external set allowedServices(JSAny value);
+  external JSAny get allowedServices;
   external set allowedManufacturerData(JSArray value);
   external JSArray get allowedManufacturerData;
 }
@@ -331,7 +331,7 @@ class BluetoothRemoteGATTServer implements JSObject {}
 
 extension BluetoothRemoteGATTServerExtension on BluetoothRemoteGATTServer {
   external JSPromise connect();
-  external JSVoid disconnect();
+  external void disconnect();
   external JSPromise getPrimaryService(BluetoothServiceUUID service);
   external JSPromise getPrimaryServices([BluetoothServiceUUID service]);
   external BluetoothDevice get device;
@@ -443,8 +443,8 @@ extension ServiceEventHandlersExtension on ServiceEventHandlers {
 @JS('BluetoothUUID')
 @staticInterop
 class BluetoothUUID implements JSObject {
-  external static UUID getService(JSAny? name);
-  external static UUID getCharacteristic(JSAny? name);
-  external static UUID getDescriptor(JSAny? name);
+  external static UUID getService(JSAny name);
+  external static UUID getCharacteristic(JSAny name);
+  external static UUID getDescriptor(JSAny name);
   external static UUID canonicalUUID(int alias);
 }
diff --git a/lib/src/dom/web_nfc.dart b/lib/src/dom/web_nfc.dart
index 95f5b48f..5ce94a0b 100644
--- a/lib/src/dom/web_nfc.dart
+++ b/lib/src/dom/web_nfc.dart
@@ -7,7 +7,7 @@ import 'dart:js_interop';
 import 'dom.dart';
 import 'html.dart';
 
-typedef NDEFMessageSource = JSAny?;
+typedef NDEFMessageSource = JSAny;
 
 @JS('NDEFMessage')
 @staticInterop
diff --git a/lib/src/dom/webaudio.dart b/lib/src/dom/webaudio.dart
index 7575ae3c..6adadb9a 100644
--- a/lib/src/dom/webaudio.dart
+++ b/lib/src/dom/webaudio.dart
@@ -91,7 +91,7 @@ extension AudioContextExtension on AudioContext {
   external JSPromise resume();
   external JSPromise suspend();
   external JSPromise close();
-  external JSPromise setSinkId(JSAny? sinkId);
+  external JSPromise setSinkId(JSAny sinkId);
   external MediaElementAudioSourceNode createMediaElementSource(
       HTMLMediaElement mediaElement);
   external MediaStreamAudioSourceNode createMediaStreamSource(
@@ -101,7 +101,7 @@ extension AudioContextExtension on AudioContext {
   external MediaStreamAudioDestinationNode createMediaStreamDestination();
   external num get baseLatency;
   external num get outputLatency;
-  external JSAny? get sinkId;
+  external JSAny get sinkId;
   external AudioRenderCapacity get renderCapacity;
   external set onsinkchange(EventHandler value);
   external EventHandler get onsinkchange;
@@ -112,22 +112,22 @@ extension AudioContextExtension on AudioContext {
 @anonymous
 class AudioContextOptions implements JSObject {
   external factory AudioContextOptions({
-    JSAny? latencyHint,
+    JSAny latencyHint,
     num sampleRate,
-    JSAny? sinkId,
-    JSAny? renderSizeHint,
+    JSAny sinkId,
+    JSAny renderSizeHint,
   });
 }
 
 extension AudioContextOptionsExtension on AudioContextOptions {
-  external set latencyHint(JSAny? value);
-  external JSAny? get latencyHint;
+  external set latencyHint(JSAny value);
+  external JSAny get latencyHint;
   external set sampleRate(num value);
   external num get sampleRate;
-  external set sinkId(JSAny? value);
-  external JSAny? get sinkId;
-  external set renderSizeHint(JSAny? value);
-  external JSAny? get renderSizeHint;
+  external set sinkId(JSAny value);
+  external JSAny get sinkId;
+  external set renderSizeHint(JSAny value);
+  external JSAny get renderSizeHint;
 }
 
 @JS()
@@ -172,8 +172,8 @@ extension AudioTimestampExtension on AudioTimestamp {
 class AudioRenderCapacity implements EventTarget {}
 
 extension AudioRenderCapacityExtension on AudioRenderCapacity {
-  external JSVoid start([AudioRenderCapacityOptions options]);
-  external JSVoid stop();
+  external void start([AudioRenderCapacityOptions options]);
+  external void stop();
   external set onupdate(EventHandler value);
   external EventHandler get onupdate;
 }
@@ -234,7 +234,7 @@ extension AudioRenderCapacityEventInitExtension
 @staticInterop
 class OfflineAudioContext implements BaseAudioContext {
   external factory OfflineAudioContext(
-    JSAny? contextOptionsOrNumberOfChannels, [
+    JSAny contextOptionsOrNumberOfChannels, [
     int length,
     num sampleRate,
   ]);
@@ -257,7 +257,7 @@ class OfflineAudioContextOptions implements JSObject {
     int numberOfChannels,
     required int length,
     required num sampleRate,
-    JSAny? renderSizeHint,
+    JSAny renderSizeHint,
   });
 }
 
@@ -268,8 +268,8 @@ extension OfflineAudioContextOptionsExtension on OfflineAudioContextOptions {
   external int get length;
   external set sampleRate(num value);
   external num get sampleRate;
-  external set renderSizeHint(JSAny? value);
-  external JSAny? get renderSizeHint;
+  external set renderSizeHint(JSAny value);
+  external JSAny get renderSizeHint;
 }
 
 @JS('OfflineAudioCompletionEvent')
@@ -307,12 +307,12 @@ class AudioBuffer implements JSObject {
 
 extension AudioBufferExtension on AudioBuffer {
   external JSFloat32Array getChannelData(int channel);
-  external JSVoid copyFromChannel(
+  external void copyFromChannel(
     JSFloat32Array destination,
     int channelNumber, [
     int bufferOffset,
   ]);
-  external JSVoid copyToChannel(
+  external void copyToChannel(
     JSFloat32Array source,
     int channelNumber, [
     int bufferOffset,
@@ -353,8 +353,8 @@ extension AudioNodeExtension on AudioNode {
     int output,
     int input,
   ]);
-  external JSVoid disconnect([
-    JSAny? destinationNodeOrDestinationParamOrOutput,
+  external void disconnect([
+    JSAny destinationNodeOrDestinationParamOrOutput,
     int output,
     int input,
   ]);
@@ -432,8 +432,8 @@ extension AudioParamExtension on AudioParam {
 class AudioScheduledSourceNode implements AudioNode {}
 
 extension AudioScheduledSourceNodeExtension on AudioScheduledSourceNode {
-  external JSVoid start([num when]);
-  external JSVoid stop([num when]);
+  external void start([num when]);
+  external void stop([num when]);
   external set onended(EventHandler value);
   external EventHandler get onended;
 }
@@ -448,10 +448,10 @@ class AnalyserNode implements AudioNode {
 }
 
 extension AnalyserNodeExtension on AnalyserNode {
-  external JSVoid getFloatFrequencyData(JSFloat32Array array);
-  external JSVoid getByteFrequencyData(JSUint8Array array);
-  external JSVoid getFloatTimeDomainData(JSFloat32Array array);
-  external JSVoid getByteTimeDomainData(JSUint8Array array);
+  external void getFloatFrequencyData(JSFloat32Array array);
+  external void getByteFrequencyData(JSUint8Array array);
+  external void getFloatTimeDomainData(JSFloat32Array array);
+  external void getByteTimeDomainData(JSUint8Array array);
   external set fftSize(int value);
   external int get fftSize;
   external int get frequencyBinCount;
@@ -496,7 +496,7 @@ class AudioBufferSourceNode implements AudioScheduledSourceNode {
 }
 
 extension AudioBufferSourceNodeExtension on AudioBufferSourceNode {
-  external JSVoid start([
+  external void start([
     num when,
     num offset,
     num duration,
@@ -555,12 +555,12 @@ extension AudioDestinationNodeExtension on AudioDestinationNode {
 class AudioListener implements JSObject {}
 
 extension AudioListenerExtension on AudioListener {
-  external JSVoid setPosition(
+  external void setPosition(
     num x,
     num y,
     num z,
   );
-  external JSVoid setOrientation(
+  external void setOrientation(
     num x,
     num y,
     num z,
@@ -624,7 +624,7 @@ class BiquadFilterNode implements AudioNode {
 }
 
 extension BiquadFilterNodeExtension on BiquadFilterNode {
-  external JSVoid getFrequencyResponse(
+  external void getFrequencyResponse(
     JSFloat32Array frequencyHz,
     JSFloat32Array magResponse,
     JSFloat32Array phaseResponse,
@@ -872,7 +872,7 @@ class IIRFilterNode implements AudioNode {
 }
 
 extension IIRFilterNodeExtension on IIRFilterNode {
-  external JSVoid getFrequencyResponse(
+  external void getFrequencyResponse(
     JSFloat32Array frequencyHz,
     JSFloat32Array magResponse,
     JSFloat32Array phaseResponse,
@@ -997,7 +997,7 @@ class OscillatorNode implements AudioScheduledSourceNode {
 }
 
 extension OscillatorNodeExtension on OscillatorNode {
-  external JSVoid setPeriodicWave(PeriodicWave periodicWave);
+  external void setPeriodicWave(PeriodicWave periodicWave);
   external set type(OscillatorType value);
   external OscillatorType get type;
   external AudioParam get frequency;
@@ -1037,12 +1037,12 @@ class PannerNode implements AudioNode {
 }
 
 extension PannerNodeExtension on PannerNode {
-  external JSVoid setPosition(
+  external void setPosition(
     num x,
     num y,
     num z,
   );
-  external JSVoid setOrientation(
+  external void setOrientation(
     num x,
     num y,
     num z,
@@ -1243,7 +1243,7 @@ extension AudioWorkletExtension on AudioWorklet {
 class AudioWorkletGlobalScope implements WorkletGlobalScope {}
 
 extension AudioWorkletGlobalScopeExtension on AudioWorkletGlobalScope {
-  external JSVoid registerProcessor(
+  external void registerProcessor(
     String name,
     AudioWorkletProcessorConstructor processorCtor,
   );
@@ -1285,7 +1285,7 @@ class AudioWorkletNodeOptions implements AudioNodeOptions {
     int numberOfInputs,
     int numberOfOutputs,
     JSArray outputChannelCount,
-    JSAny? parameterData,
+    JSAny parameterData,
     JSObject processorOptions,
   });
 }
@@ -1297,8 +1297,8 @@ extension AudioWorkletNodeOptionsExtension on AudioWorkletNodeOptions {
   external int get numberOfOutputs;
   external set outputChannelCount(JSArray value);
   external JSArray get outputChannelCount;
-  external set parameterData(JSAny? value);
-  external JSAny? get parameterData;
+  external set parameterData(JSAny value);
+  external JSAny get parameterData;
   external set processorOptions(JSObject value);
   external JSObject get processorOptions;
 }
diff --git a/lib/src/dom/webauthn.dart b/lib/src/dom/webauthn.dart
index cd48b2d2..e985e6e8 100644
--- a/lib/src/dom/webauthn.dart
+++ b/lib/src/dom/webauthn.dart
@@ -701,7 +701,7 @@ extension AuthenticationExtensionsPRFValuesExtension
 class AuthenticationExtensionsPRFInputs implements JSObject {
   external factory AuthenticationExtensionsPRFInputs({
     AuthenticationExtensionsPRFValues eval,
-    JSAny? evalByCredential,
+    JSAny evalByCredential,
   });
 }
 
@@ -709,8 +709,8 @@ extension AuthenticationExtensionsPRFInputsExtension
     on AuthenticationExtensionsPRFInputs {
   external set eval(AuthenticationExtensionsPRFValues value);
   external AuthenticationExtensionsPRFValues get eval;
-  external set evalByCredential(JSAny? value);
-  external JSAny? get evalByCredential;
+  external set evalByCredential(JSAny value);
+  external JSAny get evalByCredential;
 }
 
 @JS()
diff --git a/lib/src/dom/webcodecs.dart b/lib/src/dom/webcodecs.dart
index a4c927eb..2a2b4b7e 100644
--- a/lib/src/dom/webcodecs.dart
+++ b/lib/src/dom/webcodecs.dart
@@ -45,11 +45,11 @@ class AudioDecoder implements EventTarget {
 }
 
 extension AudioDecoderExtension on AudioDecoder {
-  external JSVoid configure(AudioDecoderConfig config);
-  external JSVoid decode(EncodedAudioChunk chunk);
+  external void configure(AudioDecoderConfig config);
+  external void decode(EncodedAudioChunk chunk);
   external JSPromise flush();
-  external JSVoid reset();
-  external JSVoid close();
+  external void reset();
+  external void close();
   external CodecState get state;
   external int get decodeQueueSize;
   external set ondequeue(EventHandler value);
@@ -82,11 +82,11 @@ class VideoDecoder implements EventTarget {
 }
 
 extension VideoDecoderExtension on VideoDecoder {
-  external JSVoid configure(VideoDecoderConfig config);
-  external JSVoid decode(EncodedVideoChunk chunk);
+  external void configure(VideoDecoderConfig config);
+  external void decode(EncodedVideoChunk chunk);
   external JSPromise flush();
-  external JSVoid reset();
-  external JSVoid close();
+  external void reset();
+  external void close();
   external CodecState get state;
   external int get decodeQueueSize;
   external set ondequeue(EventHandler value);
@@ -119,11 +119,11 @@ class AudioEncoder implements EventTarget {
 }
 
 extension AudioEncoderExtension on AudioEncoder {
-  external JSVoid configure(AudioEncoderConfig config);
-  external JSVoid encode(AudioData data);
+  external void configure(AudioEncoderConfig config);
+  external void encode(AudioData data);
   external JSPromise flush();
-  external JSVoid reset();
-  external JSVoid close();
+  external void reset();
+  external void close();
   external CodecState get state;
   external int get encodeQueueSize;
   external set ondequeue(EventHandler value);
@@ -169,14 +169,14 @@ class VideoEncoder implements EventTarget {
 }
 
 extension VideoEncoderExtension on VideoEncoder {
-  external JSVoid configure(VideoEncoderConfig config);
-  external JSVoid encode(
+  external void configure(VideoEncoderConfig config);
+  external void encode(
     VideoFrame frame, [
     VideoEncoderEncodeOptions options,
   ]);
   external JSPromise flush();
-  external JSVoid reset();
-  external JSVoid close();
+  external void reset();
+  external void close();
   external CodecState get state;
   external int get encodeQueueSize;
   external set ondequeue(EventHandler value);
@@ -485,7 +485,7 @@ class EncodedAudioChunk implements JSObject {
 }
 
 extension EncodedAudioChunkExtension on EncodedAudioChunk {
-  external JSVoid copyTo(AllowSharedBufferSource destination);
+  external void copyTo(AllowSharedBufferSource destination);
   external EncodedAudioChunkType get type;
   external int get timestamp;
   external int? get duration;
@@ -522,7 +522,7 @@ class EncodedVideoChunk implements JSObject {
 }
 
 extension EncodedVideoChunkExtension on EncodedVideoChunk {
-  external JSVoid copyTo(AllowSharedBufferSource destination);
+  external void copyTo(AllowSharedBufferSource destination);
   external EncodedVideoChunkType get type;
   external int get timestamp;
   external int? get duration;
@@ -560,12 +560,12 @@ class AudioData implements JSObject {
 
 extension AudioDataExtension on AudioData {
   external int allocationSize(AudioDataCopyToOptions options);
-  external JSVoid copyTo(
+  external void copyTo(
     AllowSharedBufferSource destination,
     AudioDataCopyToOptions options,
   );
   external AudioData clone();
-  external JSVoid close();
+  external void close();
   external AudioSampleFormat? get format;
   external num get sampleRate;
   external int get numberOfFrames;
@@ -646,7 +646,7 @@ extension VideoFrameExtension on VideoFrame {
     VideoFrameCopyToOptions options,
   ]);
   external VideoFrame clone();
-  external JSVoid close();
+  external void close();
   external VideoPixelFormat? get format;
   external int get codedWidth;
   external int get codedHeight;
@@ -823,8 +823,8 @@ class ImageDecoder implements JSObject {
 
 extension ImageDecoderExtension on ImageDecoder {
   external JSPromise decode([ImageDecodeOptions options]);
-  external JSVoid reset();
-  external JSVoid close();
+  external void reset();
+  external void close();
   external String get type;
   external bool get complete;
   external JSPromise get completed;
diff --git a/lib/src/dom/webcryptoapi.dart b/lib/src/dom/webcryptoapi.dart
index ab5f544c..7b0f6ba3 100644
--- a/lib/src/dom/webcryptoapi.dart
+++ b/lib/src/dom/webcryptoapi.dart
@@ -6,7 +6,7 @@ import 'dart:js_interop';
 
 import 'webidl.dart';
 
-typedef AlgorithmIdentifier = JSAny?;
+typedef AlgorithmIdentifier = JSAny;
 typedef HashAlgorithmIdentifier = AlgorithmIdentifier;
 typedef BigInteger = JSUint8Array;
 typedef NamedCurve = String;
diff --git a/lib/src/dom/webgl1.dart b/lib/src/dom/webgl1.dart
index 7cd64607..ebd0dfdc 100644
--- a/lib/src/dom/webgl1.dart
+++ b/lib/src/dom/webgl1.dart
@@ -426,71 +426,71 @@ extension WebGLRenderingContextBaseExtension on WebGLRenderingContextBase {
   external bool isContextLost();
   external JSArray? getSupportedExtensions();
   external JSObject? getExtension(String name);
-  external JSVoid activeTexture(GLenum texture);
-  external JSVoid attachShader(
+  external void activeTexture(GLenum texture);
+  external void attachShader(
     WebGLProgram program,
     WebGLShader shader,
   );
-  external JSVoid bindAttribLocation(
+  external void bindAttribLocation(
     WebGLProgram program,
     GLuint index,
     String name,
   );
-  external JSVoid bindBuffer(
+  external void bindBuffer(
     GLenum target,
     WebGLBuffer? buffer,
   );
-  external JSVoid bindFramebuffer(
+  external void bindFramebuffer(
     GLenum target,
     WebGLFramebuffer? framebuffer,
   );
-  external JSVoid bindRenderbuffer(
+  external void bindRenderbuffer(
     GLenum target,
     WebGLRenderbuffer? renderbuffer,
   );
-  external JSVoid bindTexture(
+  external void bindTexture(
     GLenum target,
     WebGLTexture? texture,
   );
-  external JSVoid blendColor(
+  external void blendColor(
     GLclampf red,
     GLclampf green,
     GLclampf blue,
     GLclampf alpha,
   );
-  external JSVoid blendEquation(GLenum mode);
-  external JSVoid blendEquationSeparate(
+  external void blendEquation(GLenum mode);
+  external void blendEquationSeparate(
     GLenum modeRGB,
     GLenum modeAlpha,
   );
-  external JSVoid blendFunc(
+  external void blendFunc(
     GLenum sfactor,
     GLenum dfactor,
   );
-  external JSVoid blendFuncSeparate(
+  external void blendFuncSeparate(
     GLenum srcRGB,
     GLenum dstRGB,
     GLenum srcAlpha,
     GLenum dstAlpha,
   );
   external GLenum checkFramebufferStatus(GLenum target);
-  external JSVoid clear(GLbitfield mask);
-  external JSVoid clearColor(
+  external void clear(GLbitfield mask);
+  external void clearColor(
     GLclampf red,
     GLclampf green,
     GLclampf blue,
     GLclampf alpha,
   );
-  external JSVoid clearDepth(GLclampf depth);
-  external JSVoid clearStencil(GLint s);
-  external JSVoid colorMask(
+  external void clearDepth(GLclampf depth);
+  external void clearStencil(GLint s);
+  external void colorMask(
     GLboolean red,
     GLboolean green,
     GLboolean blue,
     GLboolean alpha,
   );
-  external JSVoid compileShader(WebGLShader shader);
-  external JSVoid copyTexImage2D(
+  external void compileShader(WebGLShader shader);
+  external void copyTexImage2D(
     GLenum target,
     GLint level,
     GLenum internalformat,
@@ -500,7 +500,7 @@ extension WebGLRenderingContextBaseExtension on WebGLRenderingContextBase {
     GLsizei height,
     GLint border,
   );
-  external JSVoid copyTexSubImage2D(
+  external void copyTexSubImage2D(
     GLenum target,
     GLint level,
     GLint xoffset,
@@ -516,55 +516,55 @@ extension WebGLRenderingContextBaseExtension on WebGLRenderingContextBase {
   external WebGLRenderbuffer? createRenderbuffer();
   external WebGLShader? createShader(GLenum type);
   external WebGLTexture? createTexture();
-  external JSVoid cullFace(GLenum mode);
-  external JSVoid deleteBuffer(WebGLBuffer? buffer);
-  external JSVoid deleteFramebuffer(WebGLFramebuffer? framebuffer);
-  external JSVoid deleteProgram(WebGLProgram? program);
-  external JSVoid deleteRenderbuffer(WebGLRenderbuffer? renderbuffer);
-  external JSVoid deleteShader(WebGLShader? shader);
-  external JSVoid deleteTexture(WebGLTexture? texture);
-  external JSVoid depthFunc(GLenum func);
-  external JSVoid depthMask(GLboolean flag);
-  external JSVoid depthRange(
+  external void cullFace(GLenum mode);
+  external void deleteBuffer(WebGLBuffer? buffer);
+  external void deleteFramebuffer(WebGLFramebuffer? framebuffer);
+  external void deleteProgram(WebGLProgram? program);
+  external void deleteRenderbuffer(WebGLRenderbuffer? renderbuffer);
+  external void deleteShader(WebGLShader? shader);
+  external void deleteTexture(WebGLTexture? texture);
+  external void depthFunc(GLenum func);
+  external void depthMask(GLboolean flag);
+  external void depthRange(
     GLclampf zNear,
     GLclampf zFar,
   );
-  external JSVoid detachShader(
+  external void detachShader(
     WebGLProgram program,
     WebGLShader shader,
   );
-  external JSVoid disable(GLenum cap);
-  external JSVoid disableVertexAttribArray(GLuint index);
-  external JSVoid drawArrays(
+  external void disable(GLenum cap);
+  external void disableVertexAttribArray(GLuint index);
+  external void drawArrays(
     GLenum mode,
     GLint first,
     GLsizei count,
   );
-  external JSVoid drawElements(
+  external void drawElements(
     GLenum mode,
     GLsizei count,
     GLenum type,
     GLintptr offset,
   );
-  external JSVoid enable(GLenum cap);
-  external JSVoid enableVertexAttribArray(GLuint index);
-  external JSVoid finish();
-  external JSVoid flush();
-  external JSVoid framebufferRenderbuffer(
+  external void enable(GLenum cap);
+  external void enableVertexAttribArray(GLuint index);
+  external void finish();
+  external void flush();
+  external void framebufferRenderbuffer(
     GLenum target,
     GLenum attachment,
     GLenum renderbuffertarget,
     WebGLRenderbuffer? renderbuffer,
   );
-  external JSVoid framebufferTexture2D(
+  external void framebufferTexture2D(
     GLenum target,
     GLenum attachment,
     GLenum textarget,
     WebGLTexture? texture,
     GLint level,
   );
-  external JSVoid frontFace(GLenum mode);
-  external JSVoid generateMipmap(GLenum target);
+  external void frontFace(GLenum mode);
+  external void generateMipmap(GLenum target);
   external WebGLActiveInfo? getActiveAttrib(
     WebGLProgram program,
     GLuint index,
@@ -628,7 +628,7 @@ extension WebGLRenderingContextBaseExtension on WebGLRenderingContextBase {
     GLuint index,
     GLenum pname,
   );
-  external JSVoid hint(
+  external void hint(
     GLenum target,
     GLenum mode,
   );
@@ -639,158 +639,158 @@ extension WebGLRenderingContextBaseExtension on WebGLRenderingContextBase {
   external GLboolean isRenderbuffer(WebGLRenderbuffer? renderbuffer);
   external GLboolean isShader(WebGLShader? shader);
   external GLboolean isTexture(WebGLTexture? texture);
-  external JSVoid lineWidth(GLfloat width);
-  external JSVoid linkProgram(WebGLProgram program);
-  external JSVoid pixelStorei(
+  external void lineWidth(GLfloat width);
+  external void linkProgram(WebGLProgram program);
+  external void pixelStorei(
     GLenum pname,
     GLint param,
   );
-  external JSVoid polygonOffset(
+  external void polygonOffset(
     GLfloat factor,
     GLfloat units,
   );
-  external JSVoid renderbufferStorage(
+  external void renderbufferStorage(
     GLenum target,
     GLenum internalformat,
     GLsizei width,
     GLsizei height,
   );
-  external JSVoid sampleCoverage(
+  external void sampleCoverage(
     GLclampf value,
     GLboolean invert,
   );
-  external JSVoid scissor(
+  external void scissor(
     GLint x,
     GLint y,
     GLsizei width,
     GLsizei height,
   );
-  external JSVoid shaderSource(
+  external void shaderSource(
     WebGLShader shader,
     String source,
   );
-  external JSVoid stencilFunc(
+  external void stencilFunc(
     GLenum func,
     GLint ref,
     GLuint mask,
   );
-  external JSVoid stencilFuncSeparate(
+  external void stencilFuncSeparate(
     GLenum face,
     GLenum func,
     GLint ref,
     GLuint mask,
   );
-  external JSVoid stencilMask(GLuint mask);
-  external JSVoid stencilMaskSeparate(
+  external void stencilMask(GLuint mask);
+  external void stencilMaskSeparate(
     GLenum face,
     GLuint mask,
   );
-  external JSVoid stencilOp(
+  external void stencilOp(
     GLenum fail,
     GLenum zfail,
     GLenum zpass,
   );
-  external JSVoid stencilOpSeparate(
+  external void stencilOpSeparate(
     GLenum face,
     GLenum fail,
     GLenum zfail,
     GLenum zpass,
   );
-  external JSVoid texParameterf(
+  external void texParameterf(
     GLenum target,
     GLenum pname,
     GLfloat param,
   );
-  external JSVoid texParameteri(
+  external void texParameteri(
     GLenum target,
     GLenum pname,
     GLint param,
   );
-  external JSVoid uniform1f(
+  external void uniform1f(
     WebGLUniformLocation? location,
     GLfloat x,
   );
-  external JSVoid uniform2f(
+  external void uniform2f(
     WebGLUniformLocation? location,
     GLfloat x,
     GLfloat y,
   );
-  external JSVoid uniform3f(
+  external void uniform3f(
     WebGLUniformLocation? location,
     GLfloat x,
     GLfloat y,
     GLfloat z,
   );
-  external JSVoid uniform4f(
+  external void uniform4f(
     WebGLUniformLocation? location,
     GLfloat x,
     GLfloat y,
     GLfloat z,
     GLfloat w,
   );
-  external JSVoid uniform1i(
+  external void uniform1i(
     WebGLUniformLocation? location,
     GLint x,
   );
-  external JSVoid uniform2i(
+  external void uniform2i(
     WebGLUniformLocation? location,
     GLint x,
     GLint y,
   );
-  external JSVoid uniform3i(
+  external void uniform3i(
     WebGLUniformLocation? location,
     GLint x,
     GLint y,
     GLint z,
   );
-  external JSVoid uniform4i(
+  external void uniform4i(
     WebGLUniformLocation? location,
     GLint x,
     GLint y,
     GLint z,
     GLint w,
   );
-  external JSVoid useProgram(WebGLProgram? program);
-  external JSVoid validateProgram(WebGLProgram program);
-  external JSVoid vertexAttrib1f(
+  external void useProgram(WebGLProgram? program);
+  external void validateProgram(WebGLProgram program);
+  external void vertexAttrib1f(
     GLuint index,
     GLfloat x,
   );
-  external JSVoid vertexAttrib2f(
+  external void vertexAttrib2f(
     GLuint index,
     GLfloat x,
     GLfloat y,
   );
-  external JSVoid vertexAttrib3f(
+  external void vertexAttrib3f(
     GLuint index,
     GLfloat x,
     GLfloat y,
     GLfloat z,
   );
-  external JSVoid vertexAttrib4f(
+  external void vertexAttrib4f(
     GLuint index,
     GLfloat x,
     GLfloat y,
     GLfloat z,
     GLfloat w,
   );
-  external JSVoid vertexAttrib1fv(
+  external void vertexAttrib1fv(
     GLuint index,
     Float32List values,
   );
-  external JSVoid vertexAttrib2fv(
+  external void vertexAttrib2fv(
     GLuint index,
     Float32List values,
   );
-  external JSVoid vertexAttrib3fv(
+  external void vertexAttrib3fv(
     GLuint index,
     Float32List values,
   );
-  external JSVoid vertexAttrib4fv(
+  external void vertexAttrib4fv(
     GLuint index,
     Float32List values,
   );
-  external JSVoid vertexAttribPointer(
+  external void vertexAttribPointer(
     GLuint index,
     GLint size,
     GLenum type,
@@ -798,7 +798,7 @@ extension WebGLRenderingContextBaseExtension on WebGLRenderingContextBase {
     GLsizei stride,
     GLintptr offset,
   );
-  external JSVoid viewport(
+  external void viewport(
     GLint x,
     GLint y,
     GLsizei width,
@@ -820,17 +820,17 @@ class WebGLRenderingContextOverloads implements JSObject {}
 
 extension WebGLRenderingContextOverloadsExtension
     on WebGLRenderingContextOverloads {
-  external JSVoid bufferData(
+  external void bufferData(
     GLenum target,
-    JSAny? dataOrSize,
+    JSAny dataOrSize,
     GLenum usage,
   );
-  external JSVoid bufferSubData(
+  external void bufferSubData(
     GLenum target,
     GLintptr offset,
     AllowSharedBufferSource data,
   );
-  external JSVoid compressedTexImage2D(
+  external void compressedTexImage2D(
     GLenum target,
     GLint level,
     GLenum internalformat,
@@ -839,7 +839,7 @@ extension WebGLRenderingContextOverloadsExtension
     GLint border,
     ArrayBufferView data,
   );
-  external JSVoid compressedTexSubImage2D(
+  external void compressedTexSubImage2D(
     GLenum target,
     GLint level,
     GLint xoffset,
@@ -849,7 +849,7 @@ extension WebGLRenderingContextOverloadsExtension
     GLenum format,
     ArrayBufferView data,
   );
-  external JSVoid readPixels(
+  external void readPixels(
     GLint x,
     GLint y,
     GLsizei width,
@@ -858,71 +858,71 @@ extension WebGLRenderingContextOverloadsExtension
     GLenum type,
     ArrayBufferView? pixels,
   );
-  external JSVoid texImage2D(
+  external void texImage2D(
     GLenum target,
     GLint level,
     GLint internalformat,
-    JSAny? formatOrWidth,
-    JSAny? heightOrType,
-    JSAny? borderOrSource, [
+    JSAny formatOrWidth,
+    JSAny heightOrType,
+    JSAny borderOrSource, [
     GLenum format,
     GLenum type,
     ArrayBufferView? pixels,
   ]);
-  external JSVoid texSubImage2D(
+  external void texSubImage2D(
     GLenum target,
     GLint level,
     GLint xoffset,
     GLint yoffset,
-    JSAny? formatOrWidth,
-    JSAny? heightOrType,
-    JSAny? formatOrSource, [
+    JSAny formatOrWidth,
+    JSAny heightOrType,
+    JSAny formatOrSource, [
     GLenum type,
     ArrayBufferView? pixels,
   ]);
-  external JSVoid uniform1fv(
+  external void uniform1fv(
     WebGLUniformLocation? location,
     Float32List v,
   );
-  external JSVoid uniform2fv(
+  external void uniform2fv(
     WebGLUniformLocation? location,
     Float32List v,
   );
-  external JSVoid uniform3fv(
+  external void uniform3fv(
     WebGLUniformLocation? location,
     Float32List v,
   );
-  external JSVoid uniform4fv(
+  external void uniform4fv(
     WebGLUniformLocation? location,
     Float32List v,
   );
-  external JSVoid uniform1iv(
+  external void uniform1iv(
     WebGLUniformLocation? location,
     Int32List v,
   );
-  external JSVoid uniform2iv(
+  external void uniform2iv(
     WebGLUniformLocation? location,
     Int32List v,
   );
-  external JSVoid uniform3iv(
+  external void uniform3iv(
     WebGLUniformLocation? location,
     Int32List v,
   );
-  external JSVoid uniform4iv(
+  external void uniform4iv(
     WebGLUniformLocation? location,
     Int32List v,
   );
-  external JSVoid uniformMatrix2fv(
+  external void uniformMatrix2fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List value,
   );
-  external JSVoid uniformMatrix3fv(
+  external void uniformMatrix3fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List value,
   );
-  external JSVoid uniformMatrix4fv(
+  external void uniformMatrix4fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List value,
diff --git a/lib/src/dom/webgl2.dart b/lib/src/dom/webgl2.dart
index e5cb32a2..976d72df 100644
--- a/lib/src/dom/webgl2.dart
+++ b/lib/src/dom/webgl2.dart
@@ -300,21 +300,21 @@ class WebGL2RenderingContextBase implements JSObject {
 }
 
 extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
-  external JSVoid copyBufferSubData(
+  external void copyBufferSubData(
     GLenum readTarget,
     GLenum writeTarget,
     GLintptr readOffset,
     GLintptr writeOffset,
     GLsizeiptr size,
   );
-  external JSVoid getBufferSubData(
+  external void getBufferSubData(
     GLenum target,
     GLintptr srcByteOffset,
     ArrayBufferView dstBuffer, [
     int dstOffset,
     GLuint length,
   ]);
-  external JSVoid blitFramebuffer(
+  external void blitFramebuffer(
     GLint srcX0,
     GLint srcY0,
     GLint srcX1,
@@ -326,18 +326,18 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLbitfield mask,
     GLenum filter,
   );
-  external JSVoid framebufferTextureLayer(
+  external void framebufferTextureLayer(
     GLenum target,
     GLenum attachment,
     WebGLTexture? texture,
     GLint level,
     GLint layer,
   );
-  external JSVoid invalidateFramebuffer(
+  external void invalidateFramebuffer(
     GLenum target,
     JSArray attachments,
   );
-  external JSVoid invalidateSubFramebuffer(
+  external void invalidateSubFramebuffer(
     GLenum target,
     JSArray attachments,
     GLint x,
@@ -345,27 +345,27 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLsizei width,
     GLsizei height,
   );
-  external JSVoid readBuffer(GLenum src);
+  external void readBuffer(GLenum src);
   external JSAny? getInternalformatParameter(
     GLenum target,
     GLenum internalformat,
     GLenum pname,
   );
-  external JSVoid renderbufferStorageMultisample(
+  external void renderbufferStorageMultisample(
     GLenum target,
     GLsizei samples,
     GLenum internalformat,
     GLsizei width,
     GLsizei height,
   );
-  external JSVoid texStorage2D(
+  external void texStorage2D(
     GLenum target,
     GLsizei levels,
     GLenum internalformat,
     GLsizei width,
     GLsizei height,
   );
-  external JSVoid texStorage3D(
+  external void texStorage3D(
     GLenum target,
     GLsizei levels,
     GLenum internalformat,
@@ -373,7 +373,7 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLsizei height,
     GLsizei depth,
   );
-  external JSVoid texImage3D(
+  external void texImage3D(
     GLenum target,
     GLint level,
     GLint internalformat,
@@ -383,10 +383,10 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLint border,
     GLenum format,
     GLenum type,
-    JSAny? pboOffsetOrSourceOrSrcData, [
+    JSAny pboOffsetOrSourceOrSrcData, [
     int srcOffset,
   ]);
-  external JSVoid texSubImage3D(
+  external void texSubImage3D(
     GLenum target,
     GLint level,
     GLint xoffset,
@@ -397,10 +397,10 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLsizei depth,
     GLenum format,
     GLenum type,
-    JSAny? pboOffsetOrSourceOrSrcData, [
+    JSAny pboOffsetOrSourceOrSrcData, [
     int srcOffset,
   ]);
-  external JSVoid copyTexSubImage3D(
+  external void copyTexSubImage3D(
     GLenum target,
     GLint level,
     GLint xoffset,
@@ -411,7 +411,7 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLsizei width,
     GLsizei height,
   );
-  external JSVoid compressedTexImage3D(
+  external void compressedTexImage3D(
     GLenum target,
     GLint level,
     GLenum internalformat,
@@ -419,11 +419,11 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLsizei height,
     GLsizei depth,
     GLint border,
-    JSAny? imageSizeOrSrcData, [
-    JSAny? offsetOrSrcOffset,
+    JSAny imageSizeOrSrcData, [
+    JSAny offsetOrSrcOffset,
     GLuint srcLengthOverride,
   ]);
-  external JSVoid compressedTexSubImage3D(
+  external void compressedTexSubImage3D(
     GLenum target,
     GLint level,
     GLint xoffset,
@@ -433,149 +433,149 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLsizei height,
     GLsizei depth,
     GLenum format,
-    JSAny? imageSizeOrSrcData, [
-    JSAny? offsetOrSrcOffset,
+    JSAny imageSizeOrSrcData, [
+    JSAny offsetOrSrcOffset,
     GLuint srcLengthOverride,
   ]);
   external GLint getFragDataLocation(
     WebGLProgram program,
     String name,
   );
-  external JSVoid uniform1ui(
+  external void uniform1ui(
     WebGLUniformLocation? location,
     GLuint v0,
   );
-  external JSVoid uniform2ui(
+  external void uniform2ui(
     WebGLUniformLocation? location,
     GLuint v0,
     GLuint v1,
   );
-  external JSVoid uniform3ui(
+  external void uniform3ui(
     WebGLUniformLocation? location,
     GLuint v0,
     GLuint v1,
     GLuint v2,
   );
-  external JSVoid uniform4ui(
+  external void uniform4ui(
     WebGLUniformLocation? location,
     GLuint v0,
     GLuint v1,
     GLuint v2,
     GLuint v3,
   );
-  external JSVoid uniform1uiv(
+  external void uniform1uiv(
     WebGLUniformLocation? location,
     Uint32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform2uiv(
+  external void uniform2uiv(
     WebGLUniformLocation? location,
     Uint32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform3uiv(
+  external void uniform3uiv(
     WebGLUniformLocation? location,
     Uint32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform4uiv(
+  external void uniform4uiv(
     WebGLUniformLocation? location,
     Uint32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix3x2fv(
+  external void uniformMatrix3x2fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix4x2fv(
+  external void uniformMatrix4x2fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix2x3fv(
+  external void uniformMatrix2x3fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix4x3fv(
+  external void uniformMatrix4x3fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix2x4fv(
+  external void uniformMatrix2x4fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix3x4fv(
+  external void uniformMatrix3x4fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid vertexAttribI4i(
+  external void vertexAttribI4i(
     GLuint index,
     GLint x,
     GLint y,
     GLint z,
     GLint w,
   );
-  external JSVoid vertexAttribI4iv(
+  external void vertexAttribI4iv(
     GLuint index,
     Int32List values,
   );
-  external JSVoid vertexAttribI4ui(
+  external void vertexAttribI4ui(
     GLuint index,
     GLuint x,
     GLuint y,
     GLuint z,
     GLuint w,
   );
-  external JSVoid vertexAttribI4uiv(
+  external void vertexAttribI4uiv(
     GLuint index,
     Uint32List values,
   );
-  external JSVoid vertexAttribIPointer(
+  external void vertexAttribIPointer(
     GLuint index,
     GLint size,
     GLenum type,
     GLsizei stride,
     GLintptr offset,
   );
-  external JSVoid vertexAttribDivisor(
+  external void vertexAttribDivisor(
     GLuint index,
     GLuint divisor,
   );
-  external JSVoid drawArraysInstanced(
+  external void drawArraysInstanced(
     GLenum mode,
     GLint first,
     GLsizei count,
     GLsizei instanceCount,
   );
-  external JSVoid drawElementsInstanced(
+  external void drawElementsInstanced(
     GLenum mode,
     GLsizei count,
     GLenum type,
     GLintptr offset,
     GLsizei instanceCount,
   );
-  external JSVoid drawRangeElements(
+  external void drawRangeElements(
     GLenum mode,
     GLuint start,
     GLuint end,
@@ -583,39 +583,39 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLenum type,
     GLintptr offset,
   );
-  external JSVoid drawBuffers(JSArray buffers);
-  external JSVoid clearBufferfv(
+  external void drawBuffers(JSArray buffers);
+  external void clearBufferfv(
     GLenum buffer,
     GLint drawbuffer,
     Float32List values, [
     int srcOffset,
   ]);
-  external JSVoid clearBufferiv(
+  external void clearBufferiv(
     GLenum buffer,
     GLint drawbuffer,
     Int32List values, [
     int srcOffset,
   ]);
-  external JSVoid clearBufferuiv(
+  external void clearBufferuiv(
     GLenum buffer,
     GLint drawbuffer,
     Uint32List values, [
     int srcOffset,
   ]);
-  external JSVoid clearBufferfi(
+  external void clearBufferfi(
     GLenum buffer,
     GLint drawbuffer,
     GLfloat depth,
     GLint stencil,
   );
   external WebGLQuery? createQuery();
-  external JSVoid deleteQuery(WebGLQuery? query);
+  external void deleteQuery(WebGLQuery? query);
   external GLboolean isQuery(WebGLQuery? query);
-  external JSVoid beginQuery(
+  external void beginQuery(
     GLenum target,
     WebGLQuery query,
   );
-  external JSVoid endQuery(GLenum target);
+  external void endQuery(GLenum target);
   external WebGLQuery? getQuery(
     GLenum target,
     GLenum pname,
@@ -625,18 +625,18 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLenum pname,
   );
   external WebGLSampler? createSampler();
-  external JSVoid deleteSampler(WebGLSampler? sampler);
+  external void deleteSampler(WebGLSampler? sampler);
   external GLboolean isSampler(WebGLSampler? sampler);
-  external JSVoid bindSampler(
+  external void bindSampler(
     GLuint unit,
     WebGLSampler? sampler,
   );
-  external JSVoid samplerParameteri(
+  external void samplerParameteri(
     WebGLSampler sampler,
     GLenum pname,
     GLint param,
   );
-  external JSVoid samplerParameterf(
+  external void samplerParameterf(
     WebGLSampler sampler,
     GLenum pname,
     GLfloat param,
@@ -650,13 +650,13 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLbitfield flags,
   );
   external GLboolean isSync(WebGLSync? sync);
-  external JSVoid deleteSync(WebGLSync? sync);
+  external void deleteSync(WebGLSync? sync);
   external GLenum clientWaitSync(
     WebGLSync sync,
     GLbitfield flags,
     GLuint64 timeout,
   );
-  external JSVoid waitSync(
+  external void waitSync(
     WebGLSync sync,
     GLbitfield flags,
     GLint64 timeout,
@@ -666,15 +666,15 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     GLenum pname,
   );
   external WebGLTransformFeedback? createTransformFeedback();
-  external JSVoid deleteTransformFeedback(WebGLTransformFeedback? tf);
+  external void deleteTransformFeedback(WebGLTransformFeedback? tf);
   external GLboolean isTransformFeedback(WebGLTransformFeedback? tf);
-  external JSVoid bindTransformFeedback(
+  external void bindTransformFeedback(
     GLenum target,
     WebGLTransformFeedback? tf,
   );
-  external JSVoid beginTransformFeedback(GLenum primitiveMode);
-  external JSVoid endTransformFeedback();
-  external JSVoid transformFeedbackVaryings(
+  external void beginTransformFeedback(GLenum primitiveMode);
+  external void endTransformFeedback();
+  external void transformFeedbackVaryings(
     WebGLProgram program,
     JSArray varyings,
     GLenum bufferMode,
@@ -683,14 +683,14 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     WebGLProgram program,
     GLuint index,
   );
-  external JSVoid pauseTransformFeedback();
-  external JSVoid resumeTransformFeedback();
-  external JSVoid bindBufferBase(
+  external void pauseTransformFeedback();
+  external void resumeTransformFeedback();
+  external void bindBufferBase(
     GLenum target,
     GLuint index,
     WebGLBuffer? buffer,
   );
-  external JSVoid bindBufferRange(
+  external void bindBufferRange(
     GLenum target,
     GLuint index,
     WebGLBuffer? buffer,
@@ -723,15 +723,15 @@ extension WebGL2RenderingContextBaseExtension on WebGL2RenderingContextBase {
     WebGLProgram program,
     GLuint uniformBlockIndex,
   );
-  external JSVoid uniformBlockBinding(
+  external void uniformBlockBinding(
     WebGLProgram program,
     GLuint uniformBlockIndex,
     GLuint uniformBlockBinding,
   );
   external WebGLVertexArrayObject? createVertexArray();
-  external JSVoid deleteVertexArray(WebGLVertexArrayObject? vertexArray);
+  external void deleteVertexArray(WebGLVertexArrayObject? vertexArray);
   external GLboolean isVertexArray(WebGLVertexArrayObject? vertexArray);
-  external JSVoid bindVertexArray(WebGLVertexArrayObject? array);
+  external void bindVertexArray(WebGLVertexArrayObject? array);
 }
 
 @JS('WebGL2RenderingContextOverloads')
@@ -740,56 +740,56 @@ class WebGL2RenderingContextOverloads implements JSObject {}
 
 extension WebGL2RenderingContextOverloadsExtension
     on WebGL2RenderingContextOverloads {
-  external JSVoid bufferData(
+  external void bufferData(
     GLenum target,
-    JSAny? sizeOrSrcData,
+    JSAny sizeOrSrcData,
     GLenum usage, [
     int srcOffset,
     GLuint length,
   ]);
-  external JSVoid bufferSubData(
+  external void bufferSubData(
     GLenum target,
     GLintptr dstByteOffset,
     JSObject srcData, [
     int srcOffset,
     GLuint length,
   ]);
-  external JSVoid texImage2D(
+  external void texImage2D(
     GLenum target,
     GLint level,
     GLint internalformat,
-    JSAny? formatOrWidth,
-    JSAny? heightOrType,
-    JSAny? borderOrSource, [
+    JSAny formatOrWidth,
+    JSAny heightOrType,
+    JSAny borderOrSource, [
     GLenum format,
     GLenum type,
-    JSAny? pboOffsetOrPixelsOrSourceOrSrcData,
+    JSAny pboOffsetOrPixelsOrSourceOrSrcData,
     int srcOffset,
   ]);
-  external JSVoid texSubImage2D(
+  external void texSubImage2D(
     GLenum target,
     GLint level,
     GLint xoffset,
     GLint yoffset,
-    JSAny? formatOrWidth,
-    JSAny? heightOrType,
-    JSAny? formatOrSource, [
+    JSAny formatOrWidth,
+    JSAny heightOrType,
+    JSAny formatOrSource, [
     GLenum type,
-    JSAny? pboOffsetOrPixelsOrSourceOrSrcData,
+    JSAny pboOffsetOrPixelsOrSourceOrSrcData,
     int srcOffset,
   ]);
-  external JSVoid compressedTexImage2D(
+  external void compressedTexImage2D(
     GLenum target,
     GLint level,
     GLenum internalformat,
     GLsizei width,
     GLsizei height,
     GLint border,
-    JSAny? imageSizeOrSrcData, [
-    JSAny? offsetOrSrcOffset,
+    JSAny imageSizeOrSrcData, [
+    JSAny offsetOrSrcOffset,
     GLuint srcLengthOverride,
   ]);
-  external JSVoid compressedTexSubImage2D(
+  external void compressedTexSubImage2D(
     GLenum target,
     GLint level,
     GLint xoffset,
@@ -797,87 +797,87 @@ extension WebGL2RenderingContextOverloadsExtension
     GLsizei width,
     GLsizei height,
     GLenum format,
-    JSAny? imageSizeOrSrcData, [
-    JSAny? offsetOrSrcOffset,
+    JSAny imageSizeOrSrcData, [
+    JSAny offsetOrSrcOffset,
     GLuint srcLengthOverride,
   ]);
-  external JSVoid uniform1fv(
+  external void uniform1fv(
     WebGLUniformLocation? location,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform2fv(
+  external void uniform2fv(
     WebGLUniformLocation? location,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform3fv(
+  external void uniform3fv(
     WebGLUniformLocation? location,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform4fv(
+  external void uniform4fv(
     WebGLUniformLocation? location,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform1iv(
+  external void uniform1iv(
     WebGLUniformLocation? location,
     Int32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform2iv(
+  external void uniform2iv(
     WebGLUniformLocation? location,
     Int32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform3iv(
+  external void uniform3iv(
     WebGLUniformLocation? location,
     Int32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniform4iv(
+  external void uniform4iv(
     WebGLUniformLocation? location,
     Int32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix2fv(
+  external void uniformMatrix2fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix3fv(
+  external void uniformMatrix3fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid uniformMatrix4fv(
+  external void uniformMatrix4fv(
     WebGLUniformLocation? location,
     GLboolean transpose,
     Float32List data, [
     int srcOffset,
     GLuint srcLength,
   ]);
-  external JSVoid readPixels(
+  external void readPixels(
     GLint x,
     GLint y,
     GLsizei width,
     GLsizei height,
     GLenum format,
     GLenum type,
-    JSAny? dstDataOrOffset, [
+    JSAny dstDataOrOffset, [
     int dstOffset,
   ]);
 }
diff --git a/lib/src/dom/webgl_draw_buffers.dart b/lib/src/dom/webgl_draw_buffers.dart
index cc54507e..dd3b6a1d 100644
--- a/lib/src/dom/webgl_draw_buffers.dart
+++ b/lib/src/dom/webgl_draw_buffers.dart
@@ -46,5 +46,5 @@ class WEBGL_draw_buffers implements JSObject {
 }
 
 extension WEBGLDrawBuffersExtension on WEBGL_draw_buffers {
-  external JSVoid drawBuffersWEBGL(JSArray buffers);
+  external void drawBuffersWEBGL(JSArray buffers);
 }
diff --git a/lib/src/dom/webgl_draw_instanced_base_vertex_base_instance.dart b/lib/src/dom/webgl_draw_instanced_base_vertex_base_instance.dart
index 98d0151a..35d846f0 100644
--- a/lib/src/dom/webgl_draw_instanced_base_vertex_base_instance.dart
+++ b/lib/src/dom/webgl_draw_instanced_base_vertex_base_instance.dart
@@ -12,14 +12,14 @@ class WEBGL_draw_instanced_base_vertex_base_instance implements JSObject {}
 
 extension WEBGLDrawInstancedBaseVertexBaseInstanceExtension
     on WEBGL_draw_instanced_base_vertex_base_instance {
-  external JSVoid drawArraysInstancedBaseInstanceWEBGL(
+  external void drawArraysInstancedBaseInstanceWEBGL(
     GLenum mode,
     GLint first,
     GLsizei count,
     GLsizei instanceCount,
     GLuint baseInstance,
   );
-  external JSVoid drawElementsInstancedBaseVertexBaseInstanceWEBGL(
+  external void drawElementsInstancedBaseVertexBaseInstanceWEBGL(
     GLenum mode,
     GLsizei count,
     GLenum type,
diff --git a/lib/src/dom/webgl_lose_context.dart b/lib/src/dom/webgl_lose_context.dart
index bf3a4375..6bd01d67 100644
--- a/lib/src/dom/webgl_lose_context.dart
+++ b/lib/src/dom/webgl_lose_context.dart
@@ -9,6 +9,6 @@ import 'dart:js_interop';
 class WEBGL_lose_context implements JSObject {}
 
 extension WEBGLLoseContextExtension on WEBGL_lose_context {
-  external JSVoid loseContext();
-  external JSVoid restoreContext();
+  external void loseContext();
+  external void restoreContext();
 }
diff --git a/lib/src/dom/webgl_multi_draw.dart b/lib/src/dom/webgl_multi_draw.dart
index 2e9ea48e..e53abc4f 100644
--- a/lib/src/dom/webgl_multi_draw.dart
+++ b/lib/src/dom/webgl_multi_draw.dart
@@ -11,7 +11,7 @@ import 'webgl1.dart';
 class WEBGL_multi_draw implements JSObject {}
 
 extension WEBGLMultiDrawExtension on WEBGL_multi_draw {
-  external JSVoid multiDrawArraysWEBGL(
+  external void multiDrawArraysWEBGL(
     GLenum mode,
     JSObject firstsList,
     int firstsOffset,
@@ -19,7 +19,7 @@ extension WEBGLMultiDrawExtension on WEBGL_multi_draw {
     int countsOffset,
     GLsizei drawcount,
   );
-  external JSVoid multiDrawElementsWEBGL(
+  external void multiDrawElementsWEBGL(
     GLenum mode,
     JSObject countsList,
     int countsOffset,
@@ -28,7 +28,7 @@ extension WEBGLMultiDrawExtension on WEBGL_multi_draw {
     int offsetsOffset,
     GLsizei drawcount,
   );
-  external JSVoid multiDrawArraysInstancedWEBGL(
+  external void multiDrawArraysInstancedWEBGL(
     GLenum mode,
     JSObject firstsList,
     int firstsOffset,
@@ -38,7 +38,7 @@ extension WEBGLMultiDrawExtension on WEBGL_multi_draw {
     int instanceCountsOffset,
     GLsizei drawcount,
   );
-  external JSVoid multiDrawElementsInstancedWEBGL(
+  external void multiDrawElementsInstancedWEBGL(
     GLenum mode,
     JSObject countsList,
     int countsOffset,
diff --git a/lib/src/dom/webgl_multi_draw_instanced_base_vertex_base_instance.dart b/lib/src/dom/webgl_multi_draw_instanced_base_vertex_base_instance.dart
index 440dc8e6..4d1782bd 100644
--- a/lib/src/dom/webgl_multi_draw_instanced_base_vertex_base_instance.dart
+++ b/lib/src/dom/webgl_multi_draw_instanced_base_vertex_base_instance.dart
@@ -13,7 +13,7 @@ class WEBGL_multi_draw_instanced_base_vertex_base_instance
 
 extension WEBGLMultiDrawInstancedBaseVertexBaseInstanceExtension
     on WEBGL_multi_draw_instanced_base_vertex_base_instance {
-  external JSVoid multiDrawArraysInstancedBaseInstanceWEBGL(
+  external void multiDrawArraysInstancedBaseInstanceWEBGL(
     GLenum mode,
     JSObject firstsList,
     int firstsOffset,
@@ -25,7 +25,7 @@ extension WEBGLMultiDrawInstancedBaseVertexBaseInstanceExtension
     int baseInstancesOffset,
     GLsizei drawcount,
   );
-  external JSVoid multiDrawElementsInstancedBaseVertexBaseInstanceWEBGL(
+  external void multiDrawElementsInstancedBaseVertexBaseInstanceWEBGL(
     GLenum mode,
     JSObject countsList,
     int countsOffset,
diff --git a/lib/src/dom/webgl_provoking_vertex.dart b/lib/src/dom/webgl_provoking_vertex.dart
index 1290fd98..937ec6a9 100644
--- a/lib/src/dom/webgl_provoking_vertex.dart
+++ b/lib/src/dom/webgl_provoking_vertex.dart
@@ -15,5 +15,5 @@ class WEBGL_provoking_vertex implements JSObject {
 }
 
 extension WEBGLProvokingVertexExtension on WEBGL_provoking_vertex {
-  external JSVoid provokingVertexWEBGL(GLenum provokeMode);
+  external void provokingVertexWEBGL(GLenum provokeMode);
 }
diff --git a/lib/src/dom/webgpu.dart b/lib/src/dom/webgpu.dart
index 5b4be46e..20ef8b0d 100644
--- a/lib/src/dom/webgpu.dart
+++ b/lib/src/dom/webgpu.dart
@@ -203,7 +203,7 @@ extension GPUAdapterExtension on GPUAdapter {
 class GPUDeviceDescriptor implements GPUObjectDescriptorBase {
   external factory GPUDeviceDescriptor({
     JSArray requiredFeatures,
-    JSAny? requiredLimits,
+    JSAny requiredLimits,
     GPUQueueDescriptor defaultQueue,
   });
 }
@@ -211,8 +211,8 @@ class GPUDeviceDescriptor implements GPUObjectDescriptorBase {
 extension GPUDeviceDescriptorExtension on GPUDeviceDescriptor {
   external set requiredFeatures(JSArray value);
   external JSArray get requiredFeatures;
-  external set requiredLimits(JSAny? value);
-  external JSAny? get requiredLimits;
+  external set requiredLimits(JSAny value);
+  external JSAny get requiredLimits;
   external set defaultQueue(GPUQueueDescriptor value);
   external GPUQueueDescriptor get defaultQueue;
 }
@@ -222,7 +222,7 @@ extension GPUDeviceDescriptorExtension on GPUDeviceDescriptor {
 class GPUDevice implements EventTarget, GPUObjectBase {}
 
 extension GPUDeviceExtension on GPUDevice {
-  external JSVoid destroy();
+  external void destroy();
   external GPUBuffer createBuffer(GPUBufferDescriptor descriptor);
   external GPUTexture createTexture(GPUTextureDescriptor descriptor);
   external GPUSampler createSampler([GPUSamplerDescriptor descriptor]);
@@ -248,7 +248,7 @@ extension GPUDeviceExtension on GPUDevice {
   external GPURenderBundleEncoder createRenderBundleEncoder(
       GPURenderBundleEncoderDescriptor descriptor);
   external GPUQuerySet createQuerySet(GPUQuerySetDescriptor descriptor);
-  external JSVoid pushErrorScope(GPUErrorFilter filter);
+  external void pushErrorScope(GPUErrorFilter filter);
   external JSPromise popErrorScope();
   external GPUSupportedFeatures get features;
   external GPUSupportedLimits get limits;
@@ -272,8 +272,8 @@ extension GPUBufferExtension on GPUBuffer {
     GPUSize64 offset,
     GPUSize64 size,
   ]);
-  external JSVoid unmap();
-  external JSVoid destroy();
+  external void unmap();
+  external void destroy();
   external GPUSize64Out get size;
   external GPUFlagsConstant get usage;
   external GPUBufferMapState get mapState;
@@ -333,7 +333,7 @@ class GPUTexture implements GPUObjectBase {}
 
 extension GPUTextureExtension on GPUTexture {
   external GPUTextureView createView([GPUTextureViewDescriptor descriptor]);
-  external JSVoid destroy();
+  external void destroy();
   external GPUIntegerCoordinateOut get width;
   external GPUIntegerCoordinateOut get height;
   external GPUIntegerCoordinateOut get depthOrArrayLayers;
@@ -722,7 +722,7 @@ class GPUShaderModuleDescriptor implements GPUObjectDescriptorBase {
   external factory GPUShaderModuleDescriptor({
     required String code,
     JSObject sourceMap,
-    JSAny? hints,
+    JSAny hints,
   });
 }
 
@@ -731,21 +731,21 @@ extension GPUShaderModuleDescriptorExtension on GPUShaderModuleDescriptor {
   external String get code;
   external set sourceMap(JSObject value);
   external JSObject get sourceMap;
-  external set hints(JSAny? value);
-  external JSAny? get hints;
+  external set hints(JSAny value);
+  external JSAny get hints;
 }
 
 @JS()
 @staticInterop
 @anonymous
 class GPUShaderModuleCompilationHint implements JSObject {
-  external factory GPUShaderModuleCompilationHint({JSAny? layout});
+  external factory GPUShaderModuleCompilationHint({JSAny layout});
 }
 
 extension GPUShaderModuleCompilationHintExtension
     on GPUShaderModuleCompilationHint {
-  external set layout(JSAny? value);
-  external JSAny? get layout;
+  external set layout(JSAny value);
+  external JSAny get layout;
 }
 
 @JS('GPUCompilationMessage')
@@ -799,12 +799,12 @@ extension GPUPipelineErrorInitExtension on GPUPipelineErrorInit {
 @staticInterop
 @anonymous
 class GPUPipelineDescriptorBase implements GPUObjectDescriptorBase {
-  external factory GPUPipelineDescriptorBase({required JSAny? layout});
+  external factory GPUPipelineDescriptorBase({required JSAny layout});
 }
 
 extension GPUPipelineDescriptorBaseExtension on GPUPipelineDescriptorBase {
-  external set layout(JSAny? value);
-  external JSAny? get layout;
+  external set layout(JSAny value);
+  external JSAny get layout;
 }
 
 @JS('GPUPipelineBase')
@@ -822,7 +822,7 @@ class GPUProgrammableStage implements JSObject {
   external factory GPUProgrammableStage({
     required GPUShaderModule module,
     required String entryPoint,
-    JSAny? constants,
+    JSAny constants,
   });
 }
 
@@ -831,8 +831,8 @@ extension GPUProgrammableStageExtension on GPUProgrammableStage {
   external GPUShaderModule get module;
   external set entryPoint(String value);
   external String get entryPoint;
-  external set constants(JSAny? value);
-  external JSAny? get constants;
+  external set constants(JSAny value);
+  external JSAny get constants;
 }
 
 @JS('GPUComputePipeline')
@@ -1244,38 +1244,38 @@ extension GPUCommandEncoderExtension on GPUCommandEncoder {
       GPURenderPassDescriptor descriptor);
   external GPUComputePassEncoder beginComputePass(
       [GPUComputePassDescriptor descriptor]);
-  external JSVoid copyBufferToBuffer(
+  external void copyBufferToBuffer(
     GPUBuffer source,
     GPUSize64 sourceOffset,
     GPUBuffer destination,
     GPUSize64 destinationOffset,
     GPUSize64 size,
   );
-  external JSVoid copyBufferToTexture(
+  external void copyBufferToTexture(
     GPUImageCopyBuffer source,
     GPUImageCopyTexture destination,
     GPUExtent3D copySize,
   );
-  external JSVoid copyTextureToBuffer(
+  external void copyTextureToBuffer(
     GPUImageCopyTexture source,
     GPUImageCopyBuffer destination,
     GPUExtent3D copySize,
   );
-  external JSVoid copyTextureToTexture(
+  external void copyTextureToTexture(
     GPUImageCopyTexture source,
     GPUImageCopyTexture destination,
     GPUExtent3D copySize,
   );
-  external JSVoid clearBuffer(
+  external void clearBuffer(
     GPUBuffer buffer, [
     GPUSize64 offset,
     GPUSize64 size,
   ]);
-  external JSVoid writeTimestamp(
+  external void writeTimestamp(
     GPUQuerySet querySet,
     GPUSize32 queryIndex,
   );
-  external JSVoid resolveQuerySet(
+  external void resolveQuerySet(
     GPUQuerySet querySet,
     GPUSize32 firstQuery,
     GPUSize32 queryCount,
@@ -1297,7 +1297,7 @@ class GPUCommandEncoderDescriptor implements GPUObjectDescriptorBase {
 class GPUBindingCommandsMixin implements JSObject {}
 
 extension GPUBindingCommandsMixinExtension on GPUBindingCommandsMixin {
-  external JSVoid setBindGroup(
+  external void setBindGroup(
     GPUIndex32 index,
     GPUBindGroup? bindGroup, [
     JSObject dynamicOffsetsOrDynamicOffsetsData,
@@ -1311,9 +1311,9 @@ extension GPUBindingCommandsMixinExtension on GPUBindingCommandsMixin {
 class GPUDebugCommandsMixin implements JSObject {}
 
 extension GPUDebugCommandsMixinExtension on GPUDebugCommandsMixin {
-  external JSVoid pushDebugGroup(String groupLabel);
-  external JSVoid popDebugGroup();
-  external JSVoid insertDebugMarker(String markerLabel);
+  external void pushDebugGroup(String groupLabel);
+  external void popDebugGroup();
+  external void insertDebugMarker(String markerLabel);
 }
 
 @JS('GPUComputePassEncoder')
@@ -1326,17 +1326,17 @@ class GPUComputePassEncoder
         GPUBindingCommandsMixin {}
 
 extension GPUComputePassEncoderExtension on GPUComputePassEncoder {
-  external JSVoid setPipeline(GPUComputePipeline pipeline);
-  external JSVoid dispatchWorkgroups(
+  external void setPipeline(GPUComputePipeline pipeline);
+  external void dispatchWorkgroups(
     GPUSize32 workgroupCountX, [
     GPUSize32 workgroupCountY,
     GPUSize32 workgroupCountZ,
   ]);
-  external JSVoid dispatchWorkgroupsIndirect(
+  external void dispatchWorkgroupsIndirect(
     GPUBuffer indirectBuffer,
     GPUSize64 indirectOffset,
   );
-  external JSVoid end();
+  external void end();
 }
 
 @JS()
@@ -1384,7 +1384,7 @@ class GPURenderPassEncoder
         GPURenderCommandsMixin {}
 
 extension GPURenderPassEncoderExtension on GPURenderPassEncoder {
-  external JSVoid setViewport(
+  external void setViewport(
     num x,
     num y,
     num width,
@@ -1392,18 +1392,18 @@ extension GPURenderPassEncoderExtension on GPURenderPassEncoder {
     num minDepth,
     num maxDepth,
   );
-  external JSVoid setScissorRect(
+  external void setScissorRect(
     GPUIntegerCoordinate x,
     GPUIntegerCoordinate y,
     GPUIntegerCoordinate width,
     GPUIntegerCoordinate height,
   );
-  external JSVoid setBlendConstant(GPUColor color);
-  external JSVoid setStencilReference(GPUStencilValue reference);
-  external JSVoid beginOcclusionQuery(GPUSize32 queryIndex);
-  external JSVoid endOcclusionQuery();
-  external JSVoid executeBundles(JSArray bundles);
-  external JSVoid end();
+  external void setBlendConstant(GPUColor color);
+  external void setStencilReference(GPUStencilValue reference);
+  external void beginOcclusionQuery(GPUSize32 queryIndex);
+  external void endOcclusionQuery();
+  external void executeBundles(JSArray bundles);
+  external void end();
 }
 
 @JS()
@@ -1545,37 +1545,37 @@ extension GPURenderPassLayoutExtension on GPURenderPassLayout {
 class GPURenderCommandsMixin implements JSObject {}
 
 extension GPURenderCommandsMixinExtension on GPURenderCommandsMixin {
-  external JSVoid setPipeline(GPURenderPipeline pipeline);
-  external JSVoid setIndexBuffer(
+  external void setPipeline(GPURenderPipeline pipeline);
+  external void setIndexBuffer(
     GPUBuffer buffer,
     GPUIndexFormat indexFormat, [
     GPUSize64 offset,
     GPUSize64 size,
   ]);
-  external JSVoid setVertexBuffer(
+  external void setVertexBuffer(
     GPUIndex32 slot,
     GPUBuffer? buffer, [
     GPUSize64 offset,
     GPUSize64 size,
   ]);
-  external JSVoid draw(
+  external void draw(
     GPUSize32 vertexCount, [
     GPUSize32 instanceCount,
     GPUSize32 firstVertex,
     GPUSize32 firstInstance,
   ]);
-  external JSVoid drawIndexed(
+  external void drawIndexed(
     GPUSize32 indexCount, [
     GPUSize32 instanceCount,
     GPUSize32 firstIndex,
     GPUSignedOffset32 baseVertex,
     GPUSize32 firstInstance,
   ]);
-  external JSVoid drawIndirect(
+  external void drawIndirect(
     GPUBuffer indirectBuffer,
     GPUSize64 indirectOffset,
   );
-  external JSVoid drawIndexedIndirect(
+  external void drawIndexedIndirect(
     GPUBuffer indirectBuffer,
     GPUSize64 indirectOffset,
   );
@@ -1636,22 +1636,22 @@ class GPUQueueDescriptor implements GPUObjectDescriptorBase {
 class GPUQueue implements GPUObjectBase {}
 
 extension GPUQueueExtension on GPUQueue {
-  external JSVoid submit(JSArray commandBuffers);
+  external void submit(JSArray commandBuffers);
   external JSPromise onSubmittedWorkDone();
-  external JSVoid writeBuffer(
+  external void writeBuffer(
     GPUBuffer buffer,
     GPUSize64 bufferOffset,
     AllowSharedBufferSource data, [
     GPUSize64 dataOffset,
     GPUSize64 size,
   ]);
-  external JSVoid writeTexture(
+  external void writeTexture(
     GPUImageCopyTexture destination,
     AllowSharedBufferSource data,
     GPUImageDataLayout dataLayout,
     GPUExtent3D size,
   );
-  external JSVoid copyExternalImageToTexture(
+  external void copyExternalImageToTexture(
     GPUImageCopyExternalImage source,
     GPUImageCopyTextureTagged destination,
     GPUExtent3D copySize,
@@ -1663,7 +1663,7 @@ extension GPUQueueExtension on GPUQueue {
 class GPUQuerySet implements GPUObjectBase {}
 
 extension GPUQuerySetExtension on GPUQuerySet {
-  external JSVoid destroy();
+  external void destroy();
   external GPUQueryType get type;
   external GPUSize32Out get count;
 }
@@ -1690,8 +1690,8 @@ extension GPUQuerySetDescriptorExtension on GPUQuerySetDescriptor {
 class GPUCanvasContext implements JSObject {}
 
 extension GPUCanvasContextExtension on GPUCanvasContext {
-  external JSVoid configure(GPUCanvasConfiguration configuration);
-  external JSVoid unconfigure();
+  external void configure(GPUCanvasConfiguration configuration);
+  external void unconfigure();
   external GPUTexture getCurrentTexture();
   external JSObject get canvas;
 }
diff --git a/lib/src/dom/webmidi.dart b/lib/src/dom/webmidi.dart
index 9dc21691..1f405dc4 100644
--- a/lib/src/dom/webmidi.dart
+++ b/lib/src/dom/webmidi.dart
@@ -98,11 +98,11 @@ extension MIDIInputExtension on MIDIInput {
 class MIDIOutput implements MIDIPort {}
 
 extension MIDIOutputExtension on MIDIOutput {
-  external JSVoid send(
+  external void send(
     JSArray data, [
     DOMHighResTimeStamp timestamp,
   ]);
-  external JSVoid clear();
+  external void clear();
 }
 
 @JS('MIDIMessageEvent')
diff --git a/lib/src/dom/webnn.dart b/lib/src/dom/webnn.dart
index 303b0911..78d0c859 100644
--- a/lib/src/dom/webnn.dart
+++ b/lib/src/dom/webnn.dart
@@ -6,10 +6,10 @@ import 'dart:js_interop';
 
 import 'webgpu.dart';
 
-typedef MLNamedArrayBufferViews = JSAny?;
+typedef MLNamedArrayBufferViews = JSAny;
 typedef MLGPUResource = JSObject;
-typedef MLNamedGPUResources = JSAny?;
-typedef MLNamedOperands = JSAny?;
+typedef MLNamedGPUResources = JSAny;
+typedef MLNamedOperands = JSAny;
 typedef MLBufferView = JSObject;
 typedef MLDeviceType = String;
 typedef MLPowerPreference = String;
@@ -93,7 +93,7 @@ class MLActivation implements JSObject {}
 class MLContext implements JSObject {}
 
 extension MLContextExtension on MLContext {
-  external JSVoid computeSync(
+  external void computeSync(
     MLGraph graph,
     MLNamedArrayBufferViews inputs,
     MLNamedArrayBufferViews outputs,
@@ -128,8 +128,8 @@ extension MLComputeResultExtension on MLComputeResult {
 class MLCommandEncoder implements JSObject {}
 
 extension MLCommandEncoderExtension on MLCommandEncoder {
-  external JSVoid initializeGraph(MLGraph graph);
-  external JSVoid dispatch(
+  external void initializeGraph(MLGraph graph);
+  external void dispatch(
     MLGraph graph,
     MLNamedGPUResources inputs,
     MLNamedGPUResources outputs,
@@ -169,8 +169,8 @@ extension MLGraphBuilderExtension on MLGraphBuilder {
     MLOperandDescriptor descriptor,
   );
   external MLOperand constant(
-    JSAny? descriptorOrValue, [
-    JSAny? bufferViewOrType,
+    JSAny descriptorOrValue, [
+    JSAny bufferViewOrType,
   ]);
   external JSPromise build(MLNamedOperands outputs);
   external MLGraph buildSync(MLNamedOperands outputs);
@@ -383,7 +383,7 @@ extension MLGraphBuilderExtension on MLGraphBuilder {
   external JSObject softsign([MLOperand input]);
   external JSArray split(
     MLOperand input,
-    JSAny? splits, [
+    JSAny splits, [
     MLSplitOptions options,
   ]);
   external MLOperand squeeze(
diff --git a/lib/src/dom/webrtc.dart b/lib/src/dom/webrtc.dart
index 0180c9e4..d083b075 100644
--- a/lib/src/dom/webrtc.dart
+++ b/lib/src/dom/webrtc.dart
@@ -79,15 +79,15 @@ extension RTCConfigurationExtension on RTCConfiguration {
 @anonymous
 class RTCIceServer implements JSObject {
   external factory RTCIceServer({
-    required JSAny? urls,
+    required JSAny urls,
     String username,
     String credential,
   });
 }
 
 extension RTCIceServerExtension on RTCIceServer {
-  external set urls(JSAny? value);
-  external JSAny? get urls;
+  external set urls(JSAny value);
+  external JSAny get urls;
   external set username(String value);
   external String get username;
   external set credential(String value);
@@ -138,7 +138,7 @@ class RTCPeerConnection implements EventTarget {
 }
 
 extension RTCPeerConnectionExtension on RTCPeerConnection {
-  external JSVoid setIdentityProvider(
+  external void setIdentityProvider(
     String provider, [
     RTCIdentityProviderOptions options,
   ]);
@@ -167,10 +167,10 @@ extension RTCPeerConnectionExtension on RTCPeerConnection {
     VoidFunction successCallback,
     RTCPeerConnectionErrorCallback failureCallback,
   ]);
-  external JSVoid restartIce();
+  external void restartIce();
   external RTCConfiguration getConfiguration();
-  external JSVoid setConfiguration([RTCConfiguration configuration]);
-  external JSVoid close();
+  external void setConfiguration([RTCConfiguration configuration]);
+  external void close();
   external JSArray getSenders();
   external JSArray getReceivers();
   external JSArray getTransceivers();
@@ -178,9 +178,9 @@ extension RTCPeerConnectionExtension on RTCPeerConnection {
     MediaStreamTrack track,
     MediaStream streams,
   );
-  external JSVoid removeTrack(RTCRtpSender sender);
+  external void removeTrack(RTCRtpSender sender);
   external RTCRtpTransceiver addTransceiver(
-    JSAny? trackOrKind, [
+    JSAny trackOrKind, [
     RTCRtpTransceiverInit init,
   ]);
   external RTCDataChannel createDataChannel(
@@ -452,7 +452,7 @@ extension RTCRtpSenderExtension on RTCRtpSender {
   ]);
   external RTCRtpSendParameters getParameters();
   external JSPromise replaceTrack(MediaStreamTrack? withTrack);
-  external JSVoid setStreams(MediaStream streams);
+  external void setStreams(MediaStream streams);
   external JSPromise getStats();
   external set transform(RTCRtpTransform? value);
   external RTCRtpTransform? get transform;
@@ -721,8 +721,8 @@ class RTCRtpSynchronizationSource implements RTCRtpContributingSource {
 class RTCRtpTransceiver implements JSObject {}
 
 extension RTCRtpTransceiverExtension on RTCRtpTransceiver {
-  external JSVoid stop();
-  external JSVoid setCodecPreferences(JSArray codecs);
+  external void stop();
+  external void setCodecPreferences(JSArray codecs);
   external String? get mid;
   external RTCRtpSender get sender;
   external RTCRtpReceiver get receiver;
@@ -769,13 +769,13 @@ class RTCIceTransport implements EventTarget {
 }
 
 extension RTCIceTransportExtension on RTCIceTransport {
-  external JSVoid gather([RTCIceGatherOptions options]);
-  external JSVoid start([
+  external void gather([RTCIceGatherOptions options]);
+  external void start([
     RTCIceParameters remoteParameters,
     RTCIceRole role,
   ]);
-  external JSVoid stop();
-  external JSVoid addRemoteCandidate([RTCIceCandidateInit remoteCandidate]);
+  external void stop();
+  external void addRemoteCandidate([RTCIceCandidateInit remoteCandidate]);
   external JSArray getLocalCandidates();
   external JSArray getRemoteCandidates();
   external RTCIceCandidatePair? getSelectedCandidatePair();
@@ -891,8 +891,8 @@ extension RTCSctpTransportExtension on RTCSctpTransport {
 class RTCDataChannel implements EventTarget {}
 
 extension RTCDataChannelExtension on RTCDataChannel {
-  external JSVoid close();
-  external JSVoid send(JSAny? data);
+  external void close();
+  external void send(JSAny data);
   external RTCPriorityType get priority;
   external String get label;
   external bool get ordered;
@@ -983,7 +983,7 @@ extension RTCDataChannelEventInitExtension on RTCDataChannelEventInit {
 class RTCDTMFSender implements EventTarget {}
 
 extension RTCDTMFSenderExtension on RTCDTMFSender {
-  external JSVoid insertDTMF(
+  external void insertDTMF(
     String tones, [
     int duration,
     int interToneGap,
diff --git a/lib/src/dom/webrtc_encoded_transform.dart b/lib/src/dom/webrtc_encoded_transform.dart
index f08e8e61..4bc679e4 100644
--- a/lib/src/dom/webrtc_encoded_transform.dart
+++ b/lib/src/dom/webrtc_encoded_transform.dart
@@ -11,7 +11,7 @@ import 'webcryptoapi.dart';
 
 typedef RTCRtpTransform = JSObject;
 typedef SmallCryptoKeyID = int;
-typedef CryptoKeyID = JSAny?;
+typedef CryptoKeyID = JSAny;
 typedef SFrameTransformRole = String;
 typedef SFrameTransformErrorEventType = String;
 typedef RTCEncodedVideoFrameType = String;
diff --git a/lib/src/dom/webrtc_identity.dart b/lib/src/dom/webrtc_identity.dart
index 35bce61c..dd39bbf2 100644
--- a/lib/src/dom/webrtc_identity.dart
+++ b/lib/src/dom/webrtc_identity.dart
@@ -25,7 +25,7 @@ class RTCIdentityProviderRegistrar implements JSObject {}
 
 extension RTCIdentityProviderRegistrarExtension
     on RTCIdentityProviderRegistrar {
-  external JSVoid register(RTCIdentityProvider idp);
+  external void register(RTCIdentityProvider idp);
 }
 
 @JS()
diff --git a/lib/src/dom/webrtc_stats.dart b/lib/src/dom/webrtc_stats.dart
index a2c0b356..07c7d2ba 100644
--- a/lib/src/dom/webrtc_stats.dart
+++ b/lib/src/dom/webrtc_stats.dart
@@ -324,7 +324,7 @@ class RTCOutboundRtpStreamStats implements RTCSentRtpStreamStats {
     num totalEncodeTime,
     num totalPacketSendDelay,
     RTCQualityLimitationReason qualityLimitationReason,
-    JSAny? qualityLimitationDurations,
+    JSAny qualityLimitationDurations,
     int qualityLimitationResolutionChanges,
     int nackCount,
     int firCount,
@@ -379,8 +379,8 @@ extension RTCOutboundRtpStreamStatsExtension on RTCOutboundRtpStreamStats {
   external num get totalPacketSendDelay;
   external set qualityLimitationReason(RTCQualityLimitationReason value);
   external RTCQualityLimitationReason get qualityLimitationReason;
-  external set qualityLimitationDurations(JSAny? value);
-  external JSAny? get qualityLimitationDurations;
+  external set qualityLimitationDurations(JSAny value);
+  external JSAny get qualityLimitationDurations;
   external set qualityLimitationResolutionChanges(int value);
   external int get qualityLimitationResolutionChanges;
   external set nackCount(int value);
diff --git a/lib/src/dom/websockets.dart b/lib/src/dom/websockets.dart
index 993acec4..b62910e4 100644
--- a/lib/src/dom/websockets.dart
+++ b/lib/src/dom/websockets.dart
@@ -14,7 +14,7 @@ typedef BinaryType = String;
 class WebSocket implements EventTarget {
   external factory WebSocket(
     String url, [
-    JSAny? protocols,
+    JSAny protocols,
   ]);
 
   external static int get CONNECTING;
@@ -24,11 +24,11 @@ class WebSocket implements EventTarget {
 }
 
 extension WebSocketExtension on WebSocket {
-  external JSVoid close([
+  external void close([
     int code,
     String reason,
   ]);
-  external JSVoid send(JSAny? data);
+  external void send(JSAny data);
   external String get url;
   external int get readyState;
   external int get bufferedAmount;
diff --git a/lib/src/dom/webtransport.dart b/lib/src/dom/webtransport.dart
index d6fd83e1..119279e3 100644
--- a/lib/src/dom/webtransport.dart
+++ b/lib/src/dom/webtransport.dart
@@ -42,7 +42,7 @@ class WebTransport implements JSObject {
 
 extension WebTransportExtension on WebTransport {
   external JSPromise getStats();
-  external JSVoid close([WebTransportCloseInfo closeInfo]);
+  external void close([WebTransportCloseInfo closeInfo]);
   external JSPromise createBidirectionalStream(
       [WebTransportSendStreamOptions options]);
   external JSPromise createUnidirectionalStream(
diff --git a/lib/src/dom/webvtt.dart b/lib/src/dom/webvtt.dart
index 458679e0..b8a99e9b 100644
--- a/lib/src/dom/webvtt.dart
+++ b/lib/src/dom/webvtt.dart
@@ -7,7 +7,7 @@ import 'dart:js_interop';
 import 'dom.dart';
 import 'html.dart';
 
-typedef LineAndPositionSetting = JSAny?;
+typedef LineAndPositionSetting = JSAny;
 typedef AutoKeyword = String;
 typedef DirectionSetting = String;
 typedef LineAlignSetting = String;
diff --git a/lib/src/dom/webxr.dart b/lib/src/dom/webxr.dart
index 59982e8b..9d6f742b 100644
--- a/lib/src/dom/webxr.dart
+++ b/lib/src/dom/webxr.dart
@@ -78,11 +78,11 @@ extension XRSessionExtension on XRSession {
   external JSPromise requestHitTestSourceForTransientInput(
       XRTransientInputHitTestOptionsInit options);
   external JSPromise requestLightProbe([XRLightProbeInit options]);
-  external JSVoid updateRenderState([XRRenderStateInit state]);
+  external void updateRenderState([XRRenderStateInit state]);
   external JSPromise updateTargetFrameRate(num rate);
   external JSPromise requestReferenceSpace(XRReferenceSpaceType type);
   external int requestAnimationFrame(XRFrameRequestCallback callback);
-  external JSVoid cancelAnimationFrame(int handle);
+  external void cancelAnimationFrame(int handle);
   external JSPromise end();
   external JSArray get persistentAnchors;
   external XREnvironmentBlendMode get environmentBlendMode;
@@ -224,7 +224,7 @@ extension XRBoundedReferenceSpaceExtension on XRBoundedReferenceSpace {
 class XRView implements JSObject {}
 
 extension XRViewExtension on XRView {
-  external JSVoid requestViewportScale(num? scale);
+  external void requestViewportScale(num? scale);
   external XRCamera? get camera;
   external bool get isFirstPersonObserver;
   external XREye get eye;
diff --git a/lib/src/dom/webxr_hit_test.dart b/lib/src/dom/webxr_hit_test.dart
index f014f880..7f6efc8c 100644
--- a/lib/src/dom/webxr_hit_test.dart
+++ b/lib/src/dom/webxr_hit_test.dart
@@ -55,7 +55,7 @@ extension XRTransientInputHitTestOptionsInitExtension
 class XRHitTestSource implements JSObject {}
 
 extension XRHitTestSourceExtension on XRHitTestSource {
-  external JSVoid cancel();
+  external void cancel();
 }
 
 @JS('XRTransientInputHitTestSource')
@@ -64,7 +64,7 @@ class XRTransientInputHitTestSource implements JSObject {}
 
 extension XRTransientInputHitTestSourceExtension
     on XRTransientInputHitTestSource {
-  external JSVoid cancel();
+  external void cancel();
 }
 
 @JS('XRHitTestResult')
diff --git a/lib/src/dom/webxrlayers.dart b/lib/src/dom/webxrlayers.dart
index 1895538b..75e637f3 100644
--- a/lib/src/dom/webxrlayers.dart
+++ b/lib/src/dom/webxrlayers.dart
@@ -22,7 +22,7 @@ typedef XRTextureType = String;
 class XRCompositionLayer implements XRLayer {}
 
 extension XRCompositionLayerExtension on XRCompositionLayer {
-  external JSVoid destroy();
+  external void destroy();
   external XRLayerLayout get layout;
   external set blendTextureSourceAlpha(bool value);
   external bool get blendTextureSourceAlpha;
diff --git a/lib/src/dom/xhr.dart b/lib/src/dom/xhr.dart
index 09c837aa..3f653df5 100644
--- a/lib/src/dom/xhr.dart
+++ b/lib/src/dom/xhr.dart
@@ -9,7 +9,7 @@ import 'dom.dart';
 import 'html.dart';
 import 'trust_token_api.dart';
 
-typedef FormDataEntryValue = JSAny?;
+typedef FormDataEntryValue = JSAny;
 typedef XMLHttpRequestResponseType = String;
 
 @JS('XMLHttpRequestEventTarget')
@@ -50,25 +50,25 @@ class XMLHttpRequest implements XMLHttpRequestEventTarget {
 }
 
 extension XMLHttpRequestExtension on XMLHttpRequest {
-  external JSVoid setAttributionReporting(
+  external void setAttributionReporting(
       AttributionReportingRequestOptions options);
-  external JSVoid setPrivateToken(PrivateToken privateToken);
-  external JSVoid open(
+  external void setPrivateToken(PrivateToken privateToken);
+  external void open(
     String method,
     String url, [
     bool async,
     String? username,
     String? password,
   ]);
-  external JSVoid setRequestHeader(
+  external void setRequestHeader(
     String name,
     String value,
   );
-  external JSVoid send([JSAny? body]);
-  external JSVoid abort();
+  external void send([JSAny? body]);
+  external void abort();
   external String? getResponseHeader(String name);
   external String getAllResponseHeaders();
-  external JSVoid overrideMimeType(String mime);
+  external void overrideMimeType(String mime);
   external set onreadystatechange(EventHandler value);
   external EventHandler get onreadystatechange;
   external int get readyState;
@@ -97,18 +97,18 @@ class FormData implements JSObject {
 }
 
 extension FormDataExtension on FormData {
-  external JSVoid append(
+  external void append(
     String name,
-    JSAny? blobValueOrValue, [
+    JSAny blobValueOrValue, [
     String filename,
   ]);
-  external JSVoid delete(String name);
+  external void delete(String name);
   external FormDataEntryValue? get(String name);
   external JSArray getAll(String name);
   external bool has(String name);
-  external JSVoid set(
+  external void set(
     String name,
-    JSAny? blobValueOrValue, [
+    JSAny blobValueOrValue, [
     String filename,
   ]);
 }
diff --git a/tool/bindings_generator/translator.dart b/tool/bindings_generator/translator.dart
index f3553166..6b728778 100644
--- a/tool/bindings_generator/translator.dart
+++ b/tool/bindings_generator/translator.dart
@@ -86,17 +86,29 @@ class _Library {
   }
 }
 
-(String, bool) _computeRawTypeUnion(
-    (String, bool) rawType1, (String, bool) rawType2) {
-  if (rawType1.$1 == 'JSUndefined' || rawType2.$1 == 'JSUndefined') {
-    return (rawType1.$1 == 'JSUndefined' ? rawType2.$1 : rawType1.$1, true);
-  } else if (rawType1.$1 == rawType2.$1) {
-    return (rawType1.$1, rawType1.$2 || rawType2.$2);
+_RawType _computeRawTypeUnion(_RawType rawType1, _RawType rawType2) {
+  final type1 = rawType1.type;
+  final type2 = rawType2.type;
+  // Handle equality and sentinels.
+  if (type1 == 'JSUndefined' || type2 == 'JSUndefined') {
+    // This sentinel is only for nullability.
+    return _RawType(type1 == 'JSUndefined' ? type2 : type1, true);
+  } else if (type1 == type2) {
+    return _RawType(type1, rawType1.nullable || rawType2.nullable);
+  }
+  // If the two types are not equal, we can just use `JSNumber` as the union can
+  // never be `JSInteger` or `JSDouble` anyways.
+  if (type1 == 'JSInteger' || type1 == 'JSDouble') {
+    rawType1.type = 'JSNumber';
+  }
+  if (type2 == 'JSInteger' || type2 == 'JSDouble') {
+    rawType2.type = 'JSNumber';
   }
   // In the case of unions, we should try and get a JS type-able type to get a
   // better LUB.
-  (String, bool) getTypeForUnionCalculation((String, bool) rawType) {
-    var (type, nullable) = rawType;
+  _RawType getTypeForUnionCalculation(_RawType rawType) {
+    var type = rawType.type;
+    var nullable = rawType.nullable;
     final decl = Translator.instance!._typeToDeclaration[type];
     if (decl != null) {
       final nodeType = decl.type;
@@ -111,9 +123,9 @@ class _Library {
           break;
         case 'typedef':
           final desugared = getTypeForUnionCalculation(
-              _typeRaw((decl as idl.Typedef).idlType));
-          type = desugared.$1;
-          nullable = desugared.$2;
+              _getRawType((decl as idl.Typedef).idlType));
+          type = desugared.type;
+          nullable = desugared.nullable;
           break;
         case 'callback':
           type = 'JSFunction';
@@ -125,39 +137,31 @@ class _Library {
           throw Exception('Unhandled type $type with node type: $nodeType');
       }
     }
-    return (type, nullable);
+    return _RawType(type, nullable);
   }
 
-  final (type1, nullable1) = getTypeForUnionCalculation(rawType1);
-  final (type2, nullable2) = getTypeForUnionCalculation(rawType2);
+  final unionableType1 = getTypeForUnionCalculation(rawType1);
+  final unionableType2 = getTypeForUnionCalculation(rawType2);
 
   // We choose `JSAny` if they're not both JS types.
-  return (computeJsTypeUnion(type1, type2) ?? 'JSAny', nullable1 || nullable2);
+  return _RawType(
+      computeJsTypeUnion(unionableType1.type, unionableType2.type) ?? 'JSAny',
+      unionableType1.nullable || unionableType2.nullable);
 }
 
-/// Returns a record containing the Dart type for the given [idlType] and a bool
-/// indicating whether the type is nullable.
-(String, bool) _typeRaw(idl.IDLType idlType) {
+/// Returns a [_RawType] for the given [idl.IDLType].
+_RawType _getRawType(idl.IDLType idlType) {
   // For union types, we take the possible union of all the types using a LUB.
   if (idlType.union) {
     final types = (idlType.idlType as JSArray).toDart;
-    String? unionType;
-    var nullable = idlType.nullable;
-    for (final type in types) {
-      final rawType = _typeRaw(type as idl.IDLType);
-      if (unionType == null) {
-        unionType = rawType.$1;
-        nullable |= rawType.$2;
-      } else {
-        final union = _computeRawTypeUnion((unionType, nullable), rawType);
-        unionType = union.$1;
-        nullable = union.$2;
-      }
+    final unionType = _getRawType(types[0] as idl.IDLType);
+    for (var i = 1; i < types.length; i++) {
+      unionType.update(types[i] as idl.IDLType);
     }
-    return (unionType!, nullable);
+    return unionType..nullable |= idlType.nullable;
   }
-  final String type;
-  final nullable = idlType.nullable;
+  String type;
+  var nullable = idlType.nullable;
   if (idlType.generic.isNotEmpty) {
     // TODO(srujzs): Once we have a generic `JSArray` and `JSPromise`, we should
     // add these type parameters in. We need to be careful, however, as we
@@ -169,41 +173,48 @@ class _Library {
   } else {
     type = (idlType.idlType as JSString).toDart;
   }
-  if (typeAliases.containsKey(type)) {
-    return (typeAliases[type]!, nullable);
-  } else {
-    return (type, nullable);
-  }
+
+  // Handles types that don't exist in the set of IDL type declarations. They
+  // are either some special values or JS builtin types.
+
+  // `WindowProxy` doesn't exist as an interface in the IDL. For our purposes,
+  // `Window` is the appropriate interface.
+  if (type == 'WindowProxy') type = 'Window';
+  // `any` is marked non-nullable in the IDL, but since it is a union of
+  // `undefined`, it can be nullable for our purposes.
+  if (type == 'any') nullable = true;
+  return _RawType(idlOrBuiltinToJsTypeAliases[type] ?? type, nullable);
 }
 
-class _Type {
+/// A class representing either a type that corresponds to an IDL declaration or
+/// a `dart:js_interop` JS types (including sentinels).
+///
+/// This should not include IDL types for which there isn't a declaration e.g.
+/// `any` or a JS built-in type e.g. `ArrayBuffer`.
+class _RawType {
   String type;
-  bool isNullable;
-
-  _Type._(this.type, this.isNullable);
+  bool nullable;
 
-  factory _Type(idl.IDLType type) {
-    final (rawType, nullable) = _typeRaw(type);
-    return _Type._(rawType, nullable);
-  }
+  _RawType(this.type, this.nullable);
 
   void update(idl.IDLType idlType) {
-    final union = _computeRawTypeUnion((type, isNullable), _typeRaw(idlType));
-    type = union.$1;
-    isNullable = union.$2;
+    final union =
+        _computeRawTypeUnion(_RawType(type, nullable), _getRawType(idlType));
+    type = union.type;
+    nullable = union.nullable;
   }
 }
 
 class _Parameter {
   final Set<String> _names;
-  final _Type type;
+  final _RawType type;
   bool isOptional;
   late final String name = _generateName();
 
   _Parameter._(this._names, this.type, this.isOptional);
 
-  factory _Parameter(idl.Argument argument) =>
-      _Parameter._({argument.name}, _Type(argument.idlType), argument.optional);
+  factory _Parameter(idl.Argument argument) => _Parameter._(
+      {argument.name}, _getRawType(argument.idlType), argument.optional);
 
   String _generateName() {
     final namesList = _names.toList();
@@ -256,14 +267,14 @@ class _OverridableMember {
 class _OverridableOperation extends _OverridableMember {
   final String name;
   final bool isStatic;
-  final _Type returnType;
+  final _RawType returnType;
 
   _OverridableOperation._(
       this.name, this.isStatic, this.returnType, super.parameters);
 
   factory _OverridableOperation(idl.Operation operation) =>
       _OverridableOperation._(operation.name, operation.special == 'static',
-          _Type(operation.idlType), operation.arguments);
+          _getRawType(operation.idlType), operation.arguments);
 
   void update(idl.Operation that) {
     assert(name == that.name && isStatic == (that.special == 'static'));
@@ -432,16 +443,15 @@ class Translator {
     }
   }
 
-  code.TypeDef _typedef(String name, (String, bool) rawType) =>
-      code.TypeDef((b) => b
-        ..name = name
-        ..definition = _typeReference(rawType.$1, isNullable: rawType.$2));
+  code.TypeDef _typedef(String name, _RawType rawType) => code.TypeDef((b) => b
+    ..name = name
+    ..definition = _typeReference(rawType));
 
-  code.Method _topLevelGetter(String dartName, String getterName) =>
+  code.Method _topLevelGetter(_RawType type, String getterName) =>
       code.Method((b) => b
         ..annotations.addAll(_jsOverride(''))
         ..external = true
-        ..returns = _typeReference(dartName)
+        ..returns = _typeReference(type)
         ..name = getterName
         ..type = code.MethodType.getter);
 
@@ -453,15 +463,32 @@ class Translator {
     }
   }
 
-  code.TypeReference _typeReference(String symbol,
-      {bool isNullable = false, bool isReturn = false}) {
+  // Given a raw type, convert it to the Dart type that will be emitted by the
+  // translator.
+  code.TypeReference _typeReference(_RawType type) {
+    var dartType = type.type;
+    var nullable = type.nullable;
+
+    // Convert JS types to primitives.
+    if (dartType == 'JSBoolean') {
+      dartType = 'bool';
+    } else if (dartType == 'JSString') {
+      dartType = 'String';
+    } else if (dartType == 'JSInteger') {
+      dartType = 'int';
+    } else if (dartType == 'JSDouble' || dartType == 'JSNumber') {
+      dartType = 'num';
+    } else if (dartType == 'JSUndefined') {
+      dartType = 'void';
+      nullable = false;
+    }
     // Unfortunately, `code_builder` doesn't know the url of the library we are
     // emitting, so we have to remove it here to avoid importing ourselves.
-    var url = _typeToLibrary[symbol]?.url;
+    var url = _typeToLibrary[dartType]?.url;
 
     // JS types and core types don't have urls.
     if (url == null) {
-      if (symbol.startsWith('JS')) {
+      if (dartType.startsWith('JS')) {
         url = 'dart:js_interop';
       }
       // Else is a core type, so no import required.
@@ -470,31 +497,17 @@ class Translator {
     } else if (p.dirname(url) == p.dirname(_currentlyTranslatingUrl)) {
       url = p.basename(url);
     }
-    // Replace `JSUndefined` with `JSVoid` in return types.
-    if (isReturn && symbol == 'JSUndefined') {
-      symbol = 'JSVoid';
-      isNullable = false;
-    }
-    // In the IDL, `any` is always nullable, and thus so is `JSAny`.
-    if (symbol == 'JSAny') {
-      isNullable = true;
-    }
     return code.TypeReference((b) => b
-      ..symbol = symbol
-      ..isNullable = isNullable
+      ..symbol = dartType
+      ..isNullable = nullable
       ..url = url);
   }
 
-  code.TypeReference _idlTypeToTypeReference(idl.IDLType idlType,
-      {required bool isReturn}) {
-    final type = _typeRaw(idlType);
-    return _typeReference(type.$1, isNullable: type.$2, isReturn: isReturn);
-  }
+  code.TypeReference _idlTypeToTypeReference(idl.IDLType idlType) =>
+      _typeReference(_getRawType(idlType));
 
-  code.TypeReference _typeToTypeReference(_Type type,
-          {required bool isReturn}) =>
-      _typeReference(type.type,
-          isNullable: type.isNullable, isReturn: isReturn);
+  code.TypeReference _typeToTypeReference(_RawType type) =>
+      _typeReference(type);
 
   T _overridableMember<T>(
       _OverridableMember member,
@@ -506,7 +519,7 @@ class Translator {
     for (final rawParameter in member.parameters) {
       final parameter = code.Parameter((b) => b
         ..name = _parameterName(rawParameter.name)
-        ..type = _typeToTypeReference(rawParameter.type, isReturn: false));
+        ..type = _typeToTypeReference(rawParameter.type));
       if (rawParameter.isOptional) {
         optionalParameters.add(parameter);
       } else {
@@ -535,7 +548,7 @@ class Translator {
       final isRequired = field.required;
       final parameter = code.Parameter((b) => b
         ..name = _parameterName(field.name)
-        ..type = _idlTypeToTypeReference(field.idlType, isReturn: false)
+        ..type = _idlTypeToTypeReference(field.idlType)
         ..required = isRequired
         ..named = true);
       optionalParameters.add(parameter);
@@ -576,7 +589,7 @@ class Translator {
           ..annotations.addAll(_jsOverride(memberName.jsOverride))
           ..external = true
           ..static = operation.isStatic
-          ..returns = _typeToTypeReference(operation.returnType, isReturn: true)
+          ..returns = _typeToTypeReference(operation.returnType)
           ..name = name
           ..requiredParameters.addAll(requiredParameters)
           ..optionalParameters.addAll(optionalParameters)));
@@ -584,7 +597,7 @@ class Translator {
 
   List<code.Method> _getterSetter(
       {required String fieldName,
-      required code.Reference Function({required bool isReturn}) getType,
+      required code.Reference Function() getType,
       required bool isStatic,
       required bool readOnly}) {
     final memberName = _memberName(fieldName);
@@ -598,13 +611,13 @@ class Translator {
           ..type = code.MethodType.setter
           ..name = name
           ..requiredParameters.add(code.Parameter((b) => b
-            ..type = getType(isReturn: false)
+            ..type = getType()
             ..name = 'value'))),
       code.Method((b) => b
         ..annotations.addAll(_jsOverride(memberName.jsOverride))
         ..external = true
         ..static = isStatic
-        ..returns = getType(isReturn: true)
+        ..returns = getType()
         ..type = code.MethodType.getter
         ..name = name)
     ];
@@ -617,8 +630,7 @@ class Translator {
           required bool readOnly}) =>
       _getterSetter(
           fieldName: fieldName,
-          getType: ({required bool isReturn}) =>
-              _idlTypeToTypeReference(type, isReturn: isReturn),
+          getType: () => _idlTypeToTypeReference(type),
           isStatic: isStatic,
           readOnly: readOnly);
 
@@ -632,7 +644,7 @@ class Translator {
   code.Method _constant(idl.Constant constant) => code.Method((b) => b
     ..external = true
     ..static = true
-    ..returns = _idlTypeToTypeReference(constant.idlType, isReturn: true)
+    ..returns = _idlTypeToTypeReference(constant.idlType)
     ..type = code.MethodType.getter
     ..name = constant.name);
 
@@ -669,14 +681,14 @@ class Translator {
   List<code.Method> _operations(List<_OverridableOperation> operations) =>
       [for (final operation in operations) _operation(operation)];
 
-  code.Extension _extension(String name, List<_OverridableOperation> operations,
-          List<idl.Member> members) =>
+  code.Extension _extension(_RawType type,
+          List<_OverridableOperation> operations, List<idl.Member> members) =>
       code.Extension((b) => b
-        ..name = '${name.snakeToPascal}Extension'
-        ..on = _typeReference(name)
+        ..name = '${type.type.snakeToPascal}Extension'
+        ..on = _typeReference(type)
         ..methods.addAll(_operations(operations)
             .followedBy(_members(members))
-            .followedBy(name == 'CSSStyleDeclaration'
+            .followedBy(type.type == 'CSSStyleDeclaration'
                 ? _cssStyleDeclarationProperties()
                 : [])));
 
@@ -684,8 +696,7 @@ class Translator {
         for (final style in _cssStyleDeclarations)
           ..._getterSetter(
               fieldName: style,
-              getType: ({required bool isReturn}) =>
-                  code.TypeReference((b) => b..symbol = 'String'),
+              getType: () => code.TypeReference((b) => b..symbol = 'String'),
               isStatic: false,
               readOnly: false),
       ];
@@ -706,7 +717,8 @@ class Translator {
           ..annotations.addAll(_jsOverride(isObjectLiteral ? '' : jsName,
               staticInterop: true, objectLiteral: isObjectLiteral))
           ..name = dartClassName
-          ..implements.addAll(implements.map(_typeReference))
+          ..implements.addAll(implements
+              .map((interface) => _typeReference(_RawType(interface, false))))
           ..constructors.addAll(isObjectLiteral
               ? [_objectLiteral(members)]
               : constructor != null
@@ -743,7 +755,8 @@ class Translator {
       implements.add('JSObject');
     }
     return [
-      if (getterName != null) _topLevelGetter(dartClassName, getterName),
+      if (getterName != null)
+        _topLevelGetter(_RawType(dartClassName, false), getterName),
       _class(
           jsName: jsName,
           dartClassName: dartClassName,
@@ -755,7 +768,7 @@ class Translator {
           isAbstract: isNamespace,
           isObjectLiteral: isDictionary),
       if (operations.isNotEmpty || members.isNotEmpty)
-        _extension(dartClassName, operations, members)
+        _extension(_RawType(dartClassName, false), operations, members)
     ];
   }
 
@@ -763,18 +776,18 @@ class Translator {
     ..comments.addAll(licenseHeader)
     ..body.addAll([
       for (final typedef in library.typedefs)
-        _typedef(typedef.name, _typeRaw(typedef.idlType)),
+        _typedef(typedef.name, _getRawType(typedef.idlType)),
       // TODO(joshualitt): We should lower callbacks and callback interfaces to
       // a Dart function that takes a typed Dart function, and returns an
       // JSFunction.
       for (final callback in library.callbacks)
-        _typedef(callback.name, ('JSFunction', false)),
+        _typedef(callback.name, _RawType('JSFunction', false)),
       for (final callbackInterface in library.callbackInterfaces)
-        _typedef(callbackInterface.name, ('JSFunction', false)),
+        _typedef(callbackInterface.name, _RawType('JSFunction', false)),
       // TODO(joshualitt): Enums in the WebIDL are just strings, but we could
       // make them easier to work with on the Dart side.
       for (final enum_ in library.enums)
-        _typedef(enum_.name, ('String', false)),
+        _typedef(enum_.name, _RawType('String', false)),
       for (final interfacelike in library.interfacelikes)
         ..._interfacelike(interfacelike),
     ]));
diff --git a/tool/bindings_generator/type_aliases.dart b/tool/bindings_generator/type_aliases.dart
index cc187f04..c0261dcd 100644
--- a/tool/bindings_generator/type_aliases.dart
+++ b/tool/bindings_generator/type_aliases.dart
@@ -2,16 +2,17 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-const typeAliases = <String, String>{
+const idlOrBuiltinToJsTypeAliases = <String, String>{
   'any': 'JSAny',
   'bigint': 'JSBigInt',
   'record': 'JSAny',
   'object': 'JSObject',
   'Promise': 'JSPromise',
-  'boolean': 'bool',
+  'boolean': 'JSBoolean',
+  // Note that this is a special sentinel that doesn't actually exist in the set
+  // of JS types today (although this might in the future).
   'undefined': 'JSUndefined',
   'Function': 'JSFunction',
-  'WindowProxy': 'Window',
   'SharedArrayBuffer': 'JSObject',
 
   'ArrayBuffer': 'JSArrayBuffer',
@@ -34,26 +35,25 @@ const typeAliases = <String, String>{
   'FrozenArray': 'JSArray',
   'ObservableArray': 'JSArray',
 
-  // TODO(srujzs): We should ideally use JS types everywhere, and only change
-  // to Dart types when we are translating. However, we need to figure out what
-  // to do for `int` vs `num` as they both map to `JSNumber`.
-  // Number aliases.
-  'byte': 'int',
-  'octet': 'int',
-  'short': 'int',
-  'long': 'int',
-  'long long': 'int',
-  'unsigned short': 'int',
-  'unsigned long': 'int',
-  'unsigned long long': 'int',
-  'float': 'num',
-  'double': 'num',
-  'unrestricted double': 'num',
-  'unrestricted float': 'num',
+  // Number aliases. Like `JSUndefined`, `JSInteger` and `JSDouble` are special
+  // sentinels so that we can differentiate between `int` and `double` values
+  // when we emit Dart types.
+  'byte': 'JSInteger',
+  'octet': 'JSInteger',
+  'short': 'JSInteger',
+  'long': 'JSInteger',
+  'long long': 'JSInteger',
+  'unsigned short': 'JSInteger',
+  'unsigned long': 'JSInteger',
+  'unsigned long long': 'JSInteger',
+  'float': 'JSDouble',
+  'double': 'JSDouble',
+  'unrestricted double': 'JSDouble',
+  'unrestricted float': 'JSDouble',
 
   // String aliases.
-  'DOMString': 'String',
-  'USVString': 'String',
-  'ByteString': 'String',
-  'CSSOMString': 'String',
+  'DOMString': 'JSString',
+  'USVString': 'JSString',
+  'ByteString': 'JSString',
+  'CSSOMString': 'JSString',
 };