Baixar Dart SDK 3.12.0 per a Windows

Released on: Unreleased
Language
Private named parameters
Dart now supports private named parameters. Before 3.12, it was an error to have a named parameter that starts with an underscore:
class Point {
final int _x, _y;
// Compile error in Dart 3.11.
Point({required this._x, required this._y});
}
This means that, before 3.12, initializing a private field from a named parameter required an explicit initializer list:
class Point {
final int _x, _y;
Point({required int x, required int y})
: _x = x,
_y = y;
}
All the initializer list is doing is removing the leading _. In Dart 3.12, the language does that for you. Now you can write:
class Point {
final int _x, _y; // Private fields.
Point({required this._x, required this._y});
}
This code behaves exactly like the previous example. The initialized fields are private, but the argument names written at the call site are public:
void main() {
print(Point(x: 1, y: 2));
}
Libraries
dart:core
- The Dart VM's RegExp implementation now supports modifier spans and duplicate named capture groups.
dart:js_interop
- Breaking change in extension name of isA: isA is moved from JSAnyUtilityExtension to NullableObjectUtilExtension to support type-checking any Object?. isA<JSObject>() also now handles JS objects with no prototypes correctly and isA<JSAny>() does a non-trivial check to make sure the value is a JS value. See #56905 for more details. As JSAnyUtilityExtension is on JSAny? and NullableObjectUtilExtension is on the supertype Object?, this change is only breaking if users referred to the extension name directly, either through applying the extension directly or through using show/hide directives.
- isA<JSExportedDartFunction>() now checks whether the function is actually a JS wrapper function that is returned from Function.toJS or Function.toJSCaptureThis.
- Added JSIterableProtocol, JSIterable, JSIteratorProtocol, JSIterator, and JSIteratorResult types to model JavaScript's iteration protocols. JSArray and JSString now implement JSIterable.
- Added extension types to provide Iterable.toJSIterable, JSIterable.toDartIterable, Iterator.toJSIterator, and JSIterator.toDartIterator.
Tools
Analyzer
- The new simple_directive_paths lint and its associated fix flag and simplify unnecessarily complex import and export paths, such as those containing redundant ./ or backtracking ../ segments.
Use dart fix --code=simple_directive_paths (with either --dry-run or --apply) to bulk fix existing lint violations.
- The prefer_initializing_formals lint rule highlights named parameters that could be private named parameters.
Use dart fix --code=prefer_initializing_formals (with either --dry-run or --apply) to bulk fix existing lint violations.
- Violations of the avoid_final_parameters lint can now be fixed with dart fix --code=avoid_final_parameters.
- The analyzer now warns when a function that contains a parameter annotated with @mustBeConst is torn off.
- The invalid_runtime_check_with_js_interop_types rule now checks for JS interop types used in a catch clause's on-type and instructs users to use isA for type checks instead.
- Analyzer plugins: Initial support for 'print debugging' via new sections in the "Plugins" Insights (Diagnostics) page. When a plugin is computing lint and warning diagnostics, print calls are now redirected to the analysis server, which presents the messages in the appropriate plugin's section on the Plugins page.
- Improved support for extension types in many existing lint rules.
- Improved support for null-aware elements in existing lint rules.
- The analysis server starts up faster with the help of improved analysis options file caching. The improvement depends on the number of analysis options files in the workspace, and the number of included analysis options files. The improvement is greater for systems with slower disk access.
- Various other improvements to analysis performance.
Pub
- dart pub cache repair now, by default, only repairs the packages referenced by the current project's pubspec.lock file. For the old behavior of repairing all packages, use the --all flag.
- dart pub add and dart pub unpack now accept @ as an alternative to : for separating a package name from its version constraint.
- Git dependencies now support Git Large File Storage (LFS).
dart2wasm
- Updated deferred loading module loader API to allow batched fetching of deferred modules. The embedder now takes loadDeferredModules instead of loadDeferredModule where the new function should now expect an array of module names rather than individual module names. All the module loading functions must now also accept an instantiator callback to which they should pass the loaded results.
dart2js
- JSExportedDartFunction.toDart sometimes incorrectly returned the original Dart function even if the wrapper JS function was cast from a call to the deprecated allowInterop. Instead, to be consistent with DDC and dart2wasm, it now throws if the wrapper JS function wasn't a result of Function.toJS or Function.toJSCaptureThis.