if chains → switch expressions

dev/benchmarks/macrobenchmarks/lib/src/picture_cache.dart

@@ -209,13 +209,11 @@ class ListItem extends StatelessWidget {
  }
 
  String _convertCountToStr(int count) {
- if (count < 10000) {
- return count.toString();
- } else if (count < 100000) {
- return '${(count / 10000).toStringAsPrecision(2)}w';
- } else {
- return '${(count / 10000).floor()}w';
- }
+ return switch (count) {
+ < 10000 => count.toString(),
+ < 100000 => '${(count / 10000).toStringAsPrecision(2)}w',
+ _ => '${(count / 10000).floor()}w',
+ };
  }
 
  Widget _buildUserInfo() {

dev/benchmarks/macrobenchmarks/lib/src/web/bench_build_material_checkbox.dart

@@ -31,13 +31,11 @@ class BenchBuildMaterialCheckbox extends WidgetBuildRecorder {
  }
 
  Row _buildRow() {
- if (_isChecked == null) {
- _isChecked = true;
- } else if (_isChecked!) {
- _isChecked = false;
- } else {
- _isChecked = null;
- }
+ _isChecked = switch (_isChecked) {
+ null => true,
+ true => false,
+ false => null,
+ };
 
  return Row(
  children: List<Widget>.generate(10, (int i) {

dev/conductor/core/lib/src/start.dart

@@ -255,16 +255,14 @@ class StartContext extends Context {
  if (atBranchPoint) {
  return ReleaseType.BETA_INITIAL;
  }
-
- if (releaseChannel == 'stable') {
- if (lastVersion.type == VersionType.stable) {
- return ReleaseType.STABLE_HOTFIX;
- } else {
- return ReleaseType.STABLE_INITIAL;
- }
+ if (releaseChannel != 'stable') {
+ return ReleaseType.BETA_HOTFIX;
  }
 
- return ReleaseType.BETA_HOTFIX;
+ return switch (lastVersion.type) {
+ VersionType.stable => ReleaseType.STABLE_HOTFIX,
+ VersionType.development || VersionType.gitDescribe || VersionType.latest => ReleaseType.STABLE_INITIAL,
+ };
  }
 
  Future<void> run() async {

dev/integration_tests/flutter_gallery/lib/demo/material/backdrop_demo.dart

@@ -307,13 +307,11 @@ class _BackdropDemoState extends State<BackdropDemo> with SingleTickerProviderSt
  }
 
  final double flingVelocity = details.velocity.pixelsPerSecond.dy / _backdropHeight;
- if (flingVelocity < 0.0) {
- _controller.fling(velocity: math.max(2.0, -flingVelocity));
- } else if (flingVelocity > 0.0) {
- _controller.fling(velocity: math.min(-2.0, -flingVelocity));
- } else {
- _controller.fling(velocity: _controller.value < 0.5 ? -2.0 : 2.0);
- }
+ _controller.fling(velocity: switch (flingVelocity) {
+ < 0.0 => math.max(2.0, -flingVelocity),
+ > 0.0 => math.min(-2.0, -flingVelocity),
+ _ => _controller.value < 0.5 ? -2.0 : 2.0,
+ });
  }
 
  // Stacks a BackdropPanel, which displays the selected category, on top

dev/integration_tests/flutter_gallery/lib/demo/material/list_demo.dart

@@ -184,21 +184,18 @@ class _ListDemoState extends State<ListDemo> {
  }
 
  Widget buildListTile(BuildContext context, String item) {
- Widget? secondary;
- if (_itemType == _MaterialListType.twoLine) {
- secondary = const Text('Additional item information.');
- } else if (_itemType == _MaterialListType.threeLine) {
- secondary = const Text(
- 'Even more additional list item information appears on line three.',
- );
- }
+ final String? subtitle = switch (_itemType) {
+ _MaterialListType.oneLine || _MaterialListType.oneLineWithAvatar || null => null,
+ _MaterialListType.twoLine => 'Additional item information.',
+ _MaterialListType.threeLine => 'Even more additional list item information appears on line three.',
+ };
  return MergeSemantics(
  child: ListTile(
  isThreeLine: _itemType == _MaterialListType.threeLine,
  dense: _dense,
  leading: _showAvatars != null ? ExcludeSemantics(child: CircleAvatar(child: Text(item))) : null,
  title: Text('This item represents $item.'),
- subtitle: secondary,
+ subtitle: subtitle != null ? Text(subtitle) : null,
  trailing: _showIcons != null ? Icon(Icons.info, color: Theme.of(context).disabledColor) : null,
  ),
  );

dev/integration_tests/flutter_gallery/lib/gallery/backdrop.dart

@@ -246,13 +246,11 @@ class _BackdropState extends State<Backdrop> with SingleTickerProviderStateMixin
  }
 
  final double flingVelocity = details.velocity.pixelsPerSecond.dy / _backdropHeight;
- if (flingVelocity < 0.0) {
- _controller!.fling(velocity: math.max(2.0, -flingVelocity));
- } else if (flingVelocity > 0.0) {
- _controller!.fling(velocity: math.min(-2.0, -flingVelocity));
- } else {
- _controller!.fling(velocity: _controller!.value < 0.5 ? -2.0 : 2.0);
- }
+ _controller!.fling(velocity: switch (flingVelocity) {
+ < 0.0 => math.max(2.0, -flingVelocity),
+ > 0.0 => math.min(-2.0, -flingVelocity),
+ _ => _controller!.value < 0.5 ? -2.0 : 2.0,
+ });
  }
 
  void _toggleFrontLayer() {

dev/integration_tests/flutter_gallery/lib/gallery/syntax_highlighter.dart

@@ -337,22 +337,14 @@ class _HighlightSpan {
  }
 
  TextStyle? textStyle(SyntaxHighlighterStyle? style) {
- if (type == _HighlightType.number) {
- return style!.numberStyle;
- } else if (type == _HighlightType.comment) {
- return style!.commentStyle;
- } else if (type == _HighlightType.keyword) {
- return style!.keywordStyle;
- } else if (type == _HighlightType.string) {
- return style!.stringStyle;
- } else if (type == _HighlightType.punctuation) {
- return style!.punctuationStyle;
- } else if (type == _HighlightType.klass) {
- return style!.classStyle;
- } else if (type == _HighlightType.constant) {
- return style!.constantStyle;
- } else {
- return style!.baseStyle;
- }
+ return switch (type) {
+ _HighlightType.number => style!.numberStyle,
+ _HighlightType.comment => style!.commentStyle,
+ _HighlightType.keyword => style!.keywordStyle,
+ _HighlightType.string => style!.stringStyle,
+ _HighlightType.punctuation => style!.punctuationStyle,
+ _HighlightType.klass => style!.classStyle,
+ _HighlightType.constant => style!.constantStyle,
+ };
  }
 }

dev/integration_tests/new_gallery/lib/demos/material/cards_demo.dart

@@ -416,20 +416,15 @@ class _CardsDemoState extends State<CardsDemo> with RestorationMixin {
  for (final TravelDestination destination in destinations(context))
  Container(
  margin: const EdgeInsets.only(bottom: 8),
- child: (destination.cardType == CardType.standard)
- ? TravelDestinationItem(destination: destination)
- : destination.cardType == CardType.tappable
- ? TappableTravelDestinationItem(
- destination: destination)
- : SelectableTravelDestinationItem(
- destination: destination,
- isSelected: _isSelected.value,
- onSelected: () {
- setState(() {
- _isSelected.value = !_isSelected.value;
- });
- },
- ),
+ child: switch (destination.cardType) {
+ CardType.standard => TravelDestinationItem(destination: destination),
+ CardType.tappable => TappableTravelDestinationItem(destination: destination),
+ CardType.selectable => SelectableTravelDestinationItem(
+ destination: destination,
+ isSelected: _isSelected.value,
+ onSelected: () => setState(() { _isSelected.value = !_isSelected.value; }),
+ ),
+ },
  ),
  ],
  ),

dev/integration_tests/new_gallery/lib/demos/reference/two_pane_demo.dart

@@ -69,13 +69,10 @@ class TwoPaneDemoState extends State<TwoPaneDemo> with RestorationMixin {
  ),
  endPane: DetailsPane(
  selectedIndex: _currentIndex.value,
- onClose: widget.type == TwoPaneDemoType.smallScreen
- ? () {
- setState(() {
- _currentIndex.value = -1;
- });
- }
- : null,
+ onClose: switch (widget.type) {
+ TwoPaneDemoType.smallScreen => () => setState(() { _currentIndex.value = -1; }),
+ TwoPaneDemoType.foldable || TwoPaneDemoType.tablet => null,
+ },
  ),
  ),
  );
@@ -190,11 +187,11 @@ class SimulateScreen extends StatelessWidget {
  ),
  padding: const EdgeInsets.all(14),
  child: AspectRatio(
- aspectRatio: type == TwoPaneDemoType.foldable
-  ? foldableAspectRatio
-  : type == TwoPaneDemoType.tablet
-  ? tabletAspectRatio
-  : singleScreenAspectRatio,
+ aspectRatio: switch (type) {
+ TwoPaneDemoType.foldable => foldableAspectRatio,
+ TwoPaneDemoType.tablet => tabletAspectRatio,
+ TwoPaneDemoType.smallScreen => singleScreenAspectRatio,
+ },
  child: LayoutBuilder(builder: (BuildContext context, BoxConstraints constraints) {
  final Size size = Size(constraints.maxWidth, constraints.maxHeight);
  final Size hingeSize = Size(size.width * hingeProportion, size.height);

dev/integration_tests/new_gallery/lib/pages/settings_icon/icon.dart

@@ -34,12 +34,12 @@ class _SettingsIconPainter extends CustomPainter {
  ///
  /// The icon is aligned to the bottom-start corner.
  void _computeCenterAndScaling(Size size) {
+ final double dx = switch (Directionality.of(context)) {
+ TextDirection.rtl => size.width - unitWidth * _scaling / 2,
+ TextDirection.ltr => unitWidth * _scaling / 2,
+ };
+ _center = Offset(dx, size.height - unitHeight * _scaling / 2);
  _scaling = min(size.width / unitWidth, size.height / unitHeight);
- _center = Directionality.of(context) == TextDirection.ltr
- ? Offset(
- unitWidth * _scaling / 2, size.height - unitHeight * _scaling / 2)
- : Offset(size.width - unitWidth * _scaling / 2,
- size.height - unitHeight * _scaling / 2);
  }
 
  /// Transforms an offset in relative units into an offset in logical pixels.

dev/integration_tests/wide_gamut_test/integration_test/app_test.dart

@@ -103,21 +103,16 @@ bool _findBGR10Color(
  return foundDeepRed;
 }
 
-bool _findColor(List<Object?> result, List<double> color) {
+bool _findColor(List<dynamic> result, List<double> color) {
  expect(result, isNotNull);
  expect(result.length, 4);
- final int width = (result[0] as int?)!;
- final int height = (result[1] as int?)!;
- final String format = (result[2] as String?)!;
- if (format == 'MTLPixelFormatBGR10_XR') {
- return _findBGR10Color((result[3] as Uint8List?)!, width, height, color);
- } else if (format == 'MTLPixelFormatBGRA10_XR') {
- return _findBGRA10Color((result[3] as Uint8List?)!, width, height, color);
- } else if (format == 'MTLPixelFormatRGBA16Float') {
- return _findRGBAF16Color((result[3] as Uint8List?)!, width, height, color);
- } else {
- fail('Unsupported pixel format: $format');
- }
+ final [int width, int height, String format, Uint8List bytes] = result;
+ return switch (format) {
+ 'MTLPixelFormatBGR10_XR' => _findBGR10Color(bytes, width, height, color),
+ 'MTLPixelFormatBGRA10_XR' => _findBGRA10Color(bytes, width, height, color),
+ 'MTLPixelFormatRGBA16Float' => _findRGBAF16Color(bytes, width, height, color),
+ _ => fail('Unsupported pixel format: $format'),
+ };
 }
 
 void main() {

dev/manual_tests/lib/density.dart

@@ -163,14 +163,12 @@ class _OptionsState extends State<Options> {
  double sliderValue = 0.0;
 
  String _densityToProfile(VisualDensity density) {
- if (density == VisualDensity.standard) {
- return 'standard';
- } else if (density == VisualDensity.compact) {
- return 'compact';
- } else if (density == VisualDensity.comfortable) {
- return 'comfortable';
- }
- return 'custom';
+ return switch (density) {
+ VisualDensity.standard => 'standard',
+ VisualDensity.compact => 'compact',
+ VisualDensity.comfortable => 'comfortable',
+ _ => 'custom',
+ };
  }
 
  VisualDensity _profileToDensity(String? profile) {

dev/manual_tests/lib/page_view.dart

@@ -70,9 +70,7 @@ class PageViewAppState extends State<PageViewApp> {
 
  void switchScrollDirection() {
  setState(() {
- scrollDirection = (scrollDirection == Axis.vertical)
- ? Axis.horizontal
- : Axis.vertical;
+ scrollDirection = flipAxis(scrollDirection);
  });
  }
 
@@ -113,9 +111,7 @@ class PageViewAppState extends State<PageViewApp> {
  AppBar _buildAppBar() {
  return AppBar(
  title: const Text('PageView'),
- actions: <Widget>[
- Text(scrollDirection == Axis.horizontal ? 'horizontal' : 'vertical'),
- ],
+ actions: <Widget>[Text(scrollDirection.name)],
  );
  }
 

dev/tools/gen_defaults/lib/template.dart

@@ -169,16 +169,13 @@ abstract class TokenTemplate {
  }
 
  String? _numToString(Object? value, [int? digits]) {
- if (value == null) {
- return null;
- }
- if (value is num) {
- if (value == double.infinity) {
- return 'double.infinity';
- }
- return digits == null ? value.toString() : value.toStringAsFixed(digits);
- }
- return getToken(value as String).toString();
+ return switch (value) {
+ null => null,
+ double.infinity => 'double.infinity',
+ num() when digits == null => value.toString(),
+ num() => value.toStringAsFixed(digits!),
+ _ => getToken(value as String).toString(),
+ };
  }
 
  /// Generate an elevation value for the given component token.

dev/tools/gen_keycodes/lib/utils.dart

@@ -205,18 +205,11 @@ Map<String, String> reverseMapOfListOfString(Map<String, List<String>> inMap, vo
 ///
 /// Will modify the input map.
 Map<String, dynamic> removeEmptyValues(Map<String, dynamic> map) {
- return map..removeWhere((String key, dynamic value) {
- if (value == null) {
- return true;
- }
- if (value is Map<String, dynamic>) {
- final Map<String, dynamic> regularizedMap = removeEmptyValues(value);
- return regularizedMap.isEmpty;
- }
- if (value is Iterable<dynamic>) {
- return value.isEmpty;
- }
- return false;
+ return map..removeWhere((String key, dynamic value) => switch (value) {
+ null => true,
+ Map<String, dynamic>() => removeEmptyValues(value).isEmpty,
+ Iterable<dynamic>() => value.isEmpty,
+ _ => false,
  });
 }
 

examples/api/lib/material/snack_bar/snack_bar.2.dart

@@ -123,13 +123,10 @@ class _SnackBarExampleState extends State<SnackBarExample> {
  const Text('Multi Line Text'),
  Switch(
  value: _multiLine,
- onChanged: _snackBarBehavior == SnackBarBehavior.fixed
- ? null
- : (bool value) {
- setState(() {
- _multiLine = !_multiLine;
- });
- },
+ onChanged: switch (_snackBarBehavior) {
+ SnackBarBehavior.fixed || null => null,
+ SnackBarBehavior.floating => (bool value) => setState(() { _multiLine = !_multiLine; }),
+ },
  ),
  ],
  ),
@@ -139,13 +136,10 @@ class _SnackBarExampleState extends State<SnackBarExample> {
  value: _sliderValue,
  divisions: 20,
  label: _sliderValue.toStringAsFixed(2),
- onChanged: _snackBarBehavior == SnackBarBehavior.fixed
- ? null
- : (double value) {
- setState(() {
- _sliderValue = value;
- });
- },
+ onChanged: switch (_snackBarBehavior) {
+ SnackBarBehavior.fixed || null => null,
+ SnackBarBehavior.floating => (double value) => setState(() { _sliderValue = value; }),
+ },
  ),
  ]),
  const SizedBox(height: 16.0),