reacton_lint #

Custom lint rules for the Reacton state management library. Detects common mistakes like creating reactons inside build(), using context.read() in build(), and patterns that should use computed().

Built with custom_lint.

Installation #

Add both reacton_lint and custom_lint to your dev dependencies:

dev_dependencies:
  reacton_lint: ^0.2.0
  custom_lint: ^0.6.0

Enable custom_lint in your analysis_options.yaml:

analyzer:
  plugins:
    - custom_lint

Rules #

avoid_reacton_in_build #

Do not create reactons inside build() methods. Reactons should be declared at the top level or as static fields. Creating them in build() generates a new reacton on every rebuild, breaking identity and causing memory leaks.

// BAD
class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final counterReacton = reacton(0); // LINT: avoid_reacton_in_build
    return Text('${context.watch(counterReacton)}');
  }
}

// GOOD
final counterReacton = reacton(0, name: 'counter');

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Text('${context.watch(counterReacton)}');
  }
}

avoid_read_in_build #

Do not use context.read() inside build(). Use context.watch() instead so the widget rebuilds when the value changes. Reserve context.read() for event handlers and callbacks.

// BAD
Widget build(BuildContext context) {
  final count = context.read(counterReacton); // LINT: avoid_read_in_build
  return Text('$count');
}

// GOOD
Widget build(BuildContext context) {
  final count = context.watch(counterReacton);
  return Text('$count');
}

prefer_computed #

When you derive a value from multiple reactons inside build(), prefer using a computed() reacton. This moves the derivation out of the widget and enables caching at the graph level.

// LINT suggests using computed
Widget build(BuildContext context) {
  final first = context.watch(firstNameReacton);
  final last = context.watch(lastNameReacton);
  final full = '$first $last'; // prefer_computed
  return Text(full);
}

// BETTER
final fullNameReacton = computed<String>(
  (read) => '${read(firstNameReacton)} ${read(lastNameReacton)}',
);

Widget build(BuildContext context) {
  return Text(context.watch(fullNameReacton));
}

Documentation #

See the Reacton documentation for full API reference and guides. Source at https://github.com/sitharaj88/reacton.

License #

MIT