[web] Treeshake keymaps for web (4% code size reduction in hello world) (#75945)

packages/flutter/lib/src/services/raw_keyboard.dart

@@ -267,6 +267,17 @@ abstract class RawKeyEvent with Diagnosticable {
     String? character;
 
     final String keymap = message['keymap'] as String;
+    if (kIsWeb) {
+      final String? key = message['key'] as String?;
+      data = RawKeyEventDataWeb(
+        code: message['code'] as String? ?? '',
+        key: key ?? '',
+        metaState: message['metaState'] as int? ?? 0,
+      );
+      if (key != null && key.isNotEmpty) {
+        character = key;
+      }
+    } else {
       switch (keymap) {
         case 'android':
           data = RawKeyEventDataAndroid(
@@ -325,14 +336,6 @@ abstract class RawKeyEvent with Diagnosticable {
             character = String.fromCharCode(unicodeScalarValues);
           }
           break;
-      case 'web':
-        data = RawKeyEventDataWeb(
-          code: message['code'] as String? ?? '',
-          key: message['key'] as String? ?? '',
-          metaState: message['metaState'] as int? ?? 0,
-        );
-        character = message['key'] as String?;
-        break;
         case 'windows':
           final int characterCodePoint = message['characterCodePoint'] as int? ?? 0;
           data = RawKeyEventDataWindows(
@@ -345,6 +348,17 @@ abstract class RawKeyEvent with Diagnosticable {
             character = String.fromCharCode(characterCodePoint);
           }
           break;
+        case 'web':
+          final String? key = message['key'] as String?;
+          data = RawKeyEventDataWeb(
+            code: message['code'] as String? ?? '',
+            key: key ?? '',
+            metaState: message['metaState'] as int? ?? 0,
+          );
+          if (key != null && key.isNotEmpty) {
+            character = key;
+          }
+          break;
         default:
           /// This exception would only be hit on platforms that haven't yet
           /// implemented raw key events, but will only be triggered if the
@@ -352,7 +366,7 @@ abstract class RawKeyEvent with Diagnosticable {
           /// first place.
           throw FlutterError('Unknown keymap for key events: $keymap');
       }
-
+    }
     final String type = message['type'] as String;
     switch (type) {
       case 'keydown':

packages/flutter/test/services/raw_keyboard_test.dart

@@ -31,7 +31,7 @@ void main() {
       }
     });
     testWidgets('No character is produced for non-printables', (WidgetTester tester) async {
-      for (final String platform in <String>['linux', 'android', 'macos', 'fuchsia', 'windows']) {
+      for (final String platform in <String>['linux', 'android', 'macos', 'fuchsia', 'windows', 'web']) {
         void handleKey(RawKeyEvent event) {
           expect(event.character, isNull, reason: 'on $platform');
         }
@@ -194,7 +194,7 @@ void main() {
         await simulateKeyUpEvent(LogicalKeyboardKey.keyA, platform: platform, physicalKey: PhysicalKeyboardKey.keyA);
         expect(RawKeyboard.instance.keysPressed, isEmpty, reason: 'on $platform');
       }
-    });
+    }, skip: isBrowser); // https://github.com/flutter/flutter/issues/76741
 
     testWidgets('keysPressed modifiers are synchronized with key events on macOS', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -219,7 +219,7 @@ void main() {
           <LogicalKeyboardKey>{LogicalKeyboardKey.shiftLeft, LogicalKeyboardKey.keyA},
         ),
       );
-    });
+    }, skip: isBrowser); // This is a macOS-specific test.
 
     testWidgets('keysPressed modifiers are synchronized with key events on iOS', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -244,7 +244,7 @@ void main() {
           <LogicalKeyboardKey>{LogicalKeyboardKey.shiftLeft, LogicalKeyboardKey.keyA},
         ),
       );
-    });
+    }, skip: isBrowser); // This is an iOS-specific test.
 
     testWidgets('keysPressed modifiers are synchronized with key events on Windows', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -269,7 +269,7 @@ void main() {
           <LogicalKeyboardKey>{LogicalKeyboardKey.shiftLeft, LogicalKeyboardKey.keyA},
         ),
       );
-    });
+    }, skip: isBrowser); // This is a Windows-specific test.
 
     testWidgets('keysPressed modifiers are synchronized with key events on android', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -294,7 +294,7 @@ void main() {
           <LogicalKeyboardKey>{LogicalKeyboardKey.shiftLeft, LogicalKeyboardKey.keyA},
         ),
       );
-    });
+    }, skip: isBrowser); // This is an Android-specific test.
 
     testWidgets('keysPressed modifiers are synchronized with key events on fuchsia', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -319,7 +319,7 @@ void main() {
           <LogicalKeyboardKey>{LogicalKeyboardKey.shiftLeft, LogicalKeyboardKey.keyA},
         ),
       );
-    });
+    }, skip: isBrowser); // This is a Fuchsia-specific test.
 
     testWidgets('keysPressed modifiers are synchronized with key events on Linux GLFW', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -350,6 +350,37 @@ void main() {
           },
         ),
       );
+    }, skip: isBrowser); // This is a GLFW-specific test.
+
+    testWidgets('keysPressed modifiers are synchronized with key events on web', (WidgetTester tester) async {
+      expect(RawKeyboard.instance.keysPressed, isEmpty);
+      // Generate the data for a regular key down event.
+      final Map<String, dynamic> data = KeyEventSimulator.getKeyData(
+        LogicalKeyboardKey.keyA,
+        platform: 'web',
+        isDown: true,
+      );
+      // Change the modifiers so that they show the shift key as already down
+      // when this event is received, but it's not in keysPressed yet.
+      data['metaState'] |= RawKeyEventDataWeb.modifierShift;
+      // dispatch the modified data.
+      await ServicesBinding.instance!.defaultBinaryMessenger.handlePlatformMessage(
+        SystemChannels.keyEvent.name,
+        SystemChannels.keyEvent.codec.encodeMessage(data),
+        (ByteData? data) {},
+      );
+      expect(
+        RawKeyboard.instance.keysPressed,
+        equals(
+          <LogicalKeyboardKey>{
+            LogicalKeyboardKey.shiftLeft,
+            // Web doesn't distinguish between left and right keys, so they're
+            // all shown as down when either is pressed.
+            LogicalKeyboardKey.shiftRight,
+            LogicalKeyboardKey.keyA,
+          },
+        ),
+      );
     });
 
     testWidgets('sided modifiers without a side set return all sides on Android', (WidgetTester tester) async {
@@ -388,7 +419,7 @@ void main() {
           },
         ),
       );
-    });
+    }, skip: isBrowser); // This is an Android-specific test.
 
     testWidgets('sided modifiers without a side set return all sides on macOS', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -426,7 +457,7 @@ void main() {
           },
         ),
       );
-    });
+    }, skip: isBrowser); // This is a macOS-specific test.
 
     testWidgets('sided modifiers without a side set return all sides on iOS', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -464,7 +495,7 @@ void main() {
           },
         ),
       );
-    });
+    }, skip: isBrowser); // This is an iOS-specific test.
 
     testWidgets('sided modifiers without a side set return all sides on Windows', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -500,7 +531,7 @@ void main() {
           },
         ),
       );
-    });
+    }, skip: isBrowser); // This is a Windows-specific test.
 
     testWidgets('sided modifiers without a side set return all sides on Linux GLFW', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
@@ -539,6 +570,44 @@ void main() {
           },
         ),
       );
+    }, skip: isBrowser); // This is a GLFW-specific test.
+
+    testWidgets('sided modifiers without a side set return all sides on web', (WidgetTester tester) async {
+      expect(RawKeyboard.instance.keysPressed, isEmpty);
+      // Generate the data for a regular key down event.
+      final Map<String, dynamic> data = KeyEventSimulator.getKeyData(
+        LogicalKeyboardKey.keyA,
+        platform: 'web',
+        isDown: true,
+      );
+      // Set only the generic "shift down" modifier, without setting a side.
+      data['metaState'] |=
+        RawKeyEventDataWeb.modifierShift |
+        RawKeyEventDataWeb.modifierAlt |
+        RawKeyEventDataWeb.modifierControl |
+        RawKeyEventDataWeb.modifierMeta;
+      // dispatch the modified data.
+      await ServicesBinding.instance!.defaultBinaryMessenger.handlePlatformMessage(
+        SystemChannels.keyEvent.name,
+        SystemChannels.keyEvent.codec.encodeMessage(data),
+            (ByteData? data) {},
+      );
+      expect(
+        RawKeyboard.instance.keysPressed,
+        equals(
+          <LogicalKeyboardKey>{
+            LogicalKeyboardKey.shiftLeft,
+            LogicalKeyboardKey.shiftRight,
+            LogicalKeyboardKey.altLeft,
+            LogicalKeyboardKey.altRight,
+            LogicalKeyboardKey.controlLeft,
+            LogicalKeyboardKey.controlRight,
+            LogicalKeyboardKey.metaLeft,
+            LogicalKeyboardKey.metaRight,
+            LogicalKeyboardKey.keyA,
+          },
+        ),
+      );
     });
 
     testWidgets('RawKeyboard asserts if no keys are in keysPressed after receiving a key down event', (WidgetTester tester) async {
@@ -547,11 +616,17 @@ void main() {
       FlutterError.onError = (FlutterErrorDetails details) {
         errorDetails = details;
       };
-      try {
+
-        await ServicesBinding.instance!.defaultBinaryMessenger
+      final Map<String, dynamic> keyEventMessage;
-            .handlePlatformMessage(
+      if (kIsWeb) {
-          SystemChannels.keyEvent.name,
+        keyEventMessage = const <String, dynamic>{
-          SystemChannels.keyEvent.codec.encodeMessage(const <String, dynamic>{
+          'type': 'keydown',
+          'keymap': 'web',
+          'code': 'ShiftLeft', // Left shift code
+          'metaState': 0x0, // No shift key metaState set!
+        };
+      } else {
+        keyEventMessage = const <String, dynamic>{
           'type': 'keydown',
           'keymap': 'android',
           'keyCode': 0x3b, // Left shift key keyCode
@@ -559,7 +634,14 @@ void main() {
           'metaState': 0x0, // No shift key metaState set!
           'source': 0x101,
           'deviceId': 1,
-          }),
+        };
+      }
+
+      try {
+        await ServicesBinding.instance!.defaultBinaryMessenger
+            .handlePlatformMessage(
+          SystemChannels.keyEvent.name,
+          SystemChannels.keyEvent.codec.encodeMessage(keyEventMessage),
               (ByteData? data) {},
         );
       } finally {
@@ -837,7 +919,8 @@ void main() {
       expect(message, equals(<String, dynamic>{ 'handled': true }));
       ServicesBinding.instance!.defaultBinaryMessenger.setMockMessageHandler(SystemChannels.keyEvent.name, null);
     });
-  });
+  }, skip: isBrowser); // This is an Android-specific group.
+
   group('RawKeyEventDataFuchsia', () {
     const Map<int, _ModifierCheck> modifierTests = <int, _ModifierCheck>{
       RawKeyEventDataFuchsia.modifierAlt: _ModifierCheck(ModifierKey.altModifier, KeyboardSide.any),
@@ -951,7 +1034,7 @@ void main() {
       expect(data.logicalKey, equals(LogicalKeyboardKey.shiftLeft));
       expect(data.keyLabel, isEmpty);
     }, skip: isBrowser); // https://github.com/flutter/flutter/issues/35347
-  });
+  }, skip: isBrowser); // This is a Fuchsia-specific group.
 
   group('RawKeyEventDataMacOs', () {
     const Map<int, _ModifierCheck> modifierTests = <int, _ModifierCheck>{
@@ -1097,7 +1180,7 @@ void main() {
       expect(data.logicalKey, equals(LogicalKeyboardKey.arrowLeft));
       expect(data.logicalKey.keyLabel, isEmpty);
     }, skip: isBrowser); // https://github.com/flutter/flutter/issues/35347
-  });
+  }, skip: isBrowser); // This is a macOS-specific group.
 
   group('RawKeyEventDataIos', () {
     const Map<int, _ModifierCheck> modifierTests = <int, _ModifierCheck>{
@@ -1243,7 +1326,7 @@ void main() {
       expect(data.logicalKey, equals(LogicalKeyboardKey.arrowLeft));
       expect(data.logicalKey.keyLabel, isEmpty);
     }, skip: isBrowser); // https://github.com/flutter/flutter/issues/35347
-  });
+  }, skip: isBrowser); // This is an iOS-specific group.
 
   group('RawKeyEventDataWindows', () {
     const Map<int, _ModifierCheck> modifierTests = <int, _ModifierCheck>{
@@ -1388,7 +1471,7 @@ void main() {
       expect(data.logicalKey, equals(LogicalKeyboardKey.arrowLeft));
       expect(data.logicalKey.keyLabel, isEmpty);
     });
-  });
+  }, skip: isBrowser); // This is a Windows-specific group.
 
   group('RawKeyEventDataLinux-GFLW', () {
     const Map<int, _ModifierCheck> modifierTests = <int, _ModifierCheck>{
@@ -1572,7 +1655,7 @@ void main() {
       expect(data.logicalKey, equals(LogicalKeyboardKey.shiftLeft));
       expect(data.keyLabel, isEmpty);
     });
-  });
+  }, skip: isBrowser); // This is a GLFW-specific group.
 
   group('RawKeyEventDataLinux-GTK', () {
     const Map<int, _ModifierCheck> modifierTests = <int, _ModifierCheck>{
@@ -1756,7 +1839,7 @@ void main() {
       expect(data.logicalKey, equals(LogicalKeyboardKey.shiftLeft));
       expect(data.keyLabel, isEmpty);
     });
-  });
+  }, skip: isBrowser); // This is a GTK-specific group.
 
   group('RawKeyEventDataWeb', () {
     const Map<int, ModifierKey> modifierTests = <int, ModifierKey>{

packages/flutter/test/widgets/raw_keyboard_listener_test.dart

@@ -42,6 +42,37 @@ void main() {
     expect(typedData.modifiers, RawKeyEventDataFuchsia.modifierLeftMeta);
     expect(typedData.isModifierPressed(ModifierKey.metaModifier, side: KeyboardSide.left), isTrue);
 
+    await tester.pumpWidget(Container());
+    focusNode.dispose();
+  }, skip: isBrowser); // This is a Fuchsia-specific test.
+
+  testWidgets('Web key event', (WidgetTester tester) async {
+    final List<RawKeyEvent> events = <RawKeyEvent>[];
+
+    final FocusNode focusNode = FocusNode();
+
+    await tester.pumpWidget(
+      RawKeyboardListener(
+        focusNode: focusNode,
+        onKey: events.add,
+        child: Container(),
+      ),
+    );
+
+    focusNode.requestFocus();
+    await tester.idle();
+
+    await tester.sendKeyEvent(LogicalKeyboardKey.metaLeft, platform: 'web');
+    await tester.idle();
+
+    expect(events.length, 2);
+    expect(events[0].runtimeType, equals(RawKeyDownEvent));
+    expect(events[0].data, isA<RawKeyEventDataWeb>());
+    final RawKeyEventDataWeb typedData = events[0].data as RawKeyEventDataWeb;
+    expect(typedData.code, 'MetaLeft');
+    expect(typedData.metaState, RawKeyEventDataWeb.modifierMeta);
+    expect(typedData.isModifierPressed(ModifierKey.metaModifier, side: KeyboardSide.left), isTrue);
+
     await tester.pumpWidget(Container());
     focusNode.dispose();
   });

packages/flutter_test/lib/src/event_simulation.dart

@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:flutter/foundation.dart' show kIsWeb;
 import 'package:flutter/services.dart';
 import 'test_async_utils.dart';
 
@@ -85,6 +86,11 @@ class KeyEventSimulator {
 
   static int _getKeyCode(LogicalKeyboardKey key, String platform) {
     assert(_osIsSupported(platform), 'Platform $platform not supported for key simulation');
+    if (kIsWeb) {
+      // web doesn't have int type code. This check is used to treeshake
+      // keyboard map code.
+      return -1;
+    } else {
       late Map<int, LogicalKeyboardKey> map;
       switch (platform) {
         case 'android':
@@ -100,7 +106,7 @@ class KeyEventSimulator {
         // iOS doesn't do key codes, just scan codes.
           return -1;
         case 'web':
-        // web doesn't have int type code
+          // web doesn't have int type code.
           return -1;
         case 'linux':
           map = kGlfwToLogicalKey;
@@ -119,6 +125,8 @@ class KeyEventSimulator {
       assert(keyCode != null, 'Key $key not found in $platform keyCode map');
       return keyCode!;
     }
+  }
+
   static String _getWebKeyCode(LogicalKeyboardKey key) {
     String? result;
     for (final String code in kWebToLogicalKey.keys) {
@@ -134,6 +142,10 @@ class KeyEventSimulator {
   static PhysicalKeyboardKey _findPhysicalKey(LogicalKeyboardKey key, String platform) {
     assert(_osIsSupported(platform), 'Platform $platform not supported for key simulation');
     late Map<dynamic, PhysicalKeyboardKey> map;
+    if (kIsWeb) {
+      // This check is used to treeshake keymap code.
+      map = kWebToPhysicalKey;
+    } else {
       switch (platform) {
         case 'android':
           map = kAndroidToPhysicalKey;
@@ -157,6 +169,7 @@ class KeyEventSimulator {
           map = kWindowsToPhysicalKey;
           break;
       }
+    }
     PhysicalKeyboardKey? result;
     for (final PhysicalKeyboardKey physicalKey in map.values) {
       if (key.debugName == physicalKey.debugName) {
@@ -191,6 +204,13 @@ class KeyEventSimulator {
       'keymap': platform,
     };
 
+    if (kIsWeb) {
+      result['code'] = _getWebKeyCode(key);
+      result['key'] = key.keyLabel;
+      result['metaState'] = _getWebModifierFlags(key, isDown);
+      return result;
+    }
+
     switch (platform) {
       case 'android':
         result['keyCode'] = keyCode;