六月

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You learned Flutter. You learned setState. It clicked.
Then you added a library and suddenly you're learning a new framework inside your framework — providers, stores, atoms, streams, reducers.

June refuses to do that.

It gives you shared, reactive state that works exactly like Flutter's own state management — just without the widget tree dependency. That's it.

At a glance

class _CounterState extends State<Counter> {
  int count = 0;         // 🔒 only this widget
                         //    can touch this

  @override
  Widget build(BuildContext context) {
    return Text('$count');
  }
}

class CounterVM extends JuneState {
  int count = 0;         // ✅ any widget,
                         //    any file,
}                        //    anywhere

JuneBuilder(
  () => CounterVM(),
  builder: (vm) => Text('${vm.count}'),
)

Why June wins on simplicity

Installation

dependencies:
  june: ^1.0.2

flutter pub get

Quick start — 3 steps, 3 minutes

Step 1 — Define your state

class CounterVM extends JuneState {
  int count = 0;
}

Step 2 — Subscribe a widget

JuneBuilder(
  () => CounterVM(),
  builder: (vm) => Text('${vm.count}'),
)

Step 3 — Update from anywhere

June.getState(() => CounterVM())
  ..count++
  ..setState();

No providers. No streams. No boilerplate. setState works the same way it always has — just across the whole app.

Full runnable example

import 'package:flutter/material.dart';
import 'package:june/june.dart';

void main() => runApp(const MyApp());

// ─── State ─────────────────────────────────────────────────────────────────

class CounterVM extends JuneState {
  int count = 0;

  void increment() {
    count++;
    setState();
  }
}

// ─── UI ────────────────────────────────────────────────────────────────────

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: JuneBuilder(
            () => CounterVM(),
            builder: (vm) => Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                const Text('You have pushed the button this many times:'),
                Text(
                  '${vm.count}',
                  style: Theme.of(context).textTheme.headlineMedium,
                ),
              ],
            ),
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => June.getState(() => CounterVM()).increment(),
          child: const Icon(Icons.add),
        ),
      ),
    );
  }
}

Patterns

Methods on state

Keep logic next to data. Call it from anywhere.

class CounterVM extends JuneState {
  int count = 0;

  void increment() {
    count++;
    setState();
  }

  void reset() {
    count = 0;
    setState();
  }
}

// From a button, a gesture, a timer — anywhere
June.getState(() => CounterVM()).increment();

Multiple instances with tag

One state class, many independent instances — perfect for list items, cards, feeds.

JuneBuilder(
  () => CounterVM(),
  builder: (vm) => Text('Default: ${vm.count}'),
)

JuneBuilder(
  () => CounterVM(),
  tag: 'card_a',
  builder: (vm) => Text('Card A: ${vm.count}'),
)

JuneBuilder(
  () => CounterVM(),
  tag: 'card_b',
  builder: (vm) => Text('Card B: ${vm.count}'),
)

// Update only card A — other instances are unaffected
June.getState(() => CounterVM(), tag: 'card_a')
  ..count++
  ..setState();

Per-widget local state with global: false

For state that belongs to exactly one widget — not shared globally. Pass your own instance and June won't register it.

class SliderState extends JuneState {
  double value = 0.5;
}

final sliderState = SliderState();

JuneBuilder(
  () => sliderState,
  global: false,
  builder: (s) => Slider(
    value: s.value,
    onChanged: (v) {
      s.value = v;
      s.setState();
    },
  ),
)

Each widget holds its own isolated state. Navigating away and back creates a fresh instance — exactly what you want for forms, sliders, and single-use UI.

Theme toggle

JuneBuilder can wrap MaterialApp itself, rebuilding the entire app on state change.

class ThemeController extends JuneState {
  bool isDark = false;

  void toggle() {
    isDark = !isDark;
    setState();
  }
}

return JuneBuilder(
  () => ThemeController(),
  builder: (c) => MaterialApp(
    theme: ThemeData.light(),
    darkTheme: ThemeData.dark(),
    themeMode: c.isDark ? ThemeMode.dark : ThemeMode.light,
    home: const HomeScreen(),
  ),
);

Async state / HTTP

Call setState() when your data arrives. Works with any Future or Stream.

class UserController extends JuneState {
  User? user;
  bool loading = false;

  Future<void> loadUser(String id) async {
    loading = true;
    setState();

    user = await userRepository.fetch(id);
    loading = false;
    setState();
  }
}

JuneBuilder(
  () => UserController(),
  builder: (c) {
    if (c.loading) return const CircularProgressIndicator();
    if (c.user == null) return const Text('No user loaded');
    return Text('Hello, ${c.user!.name}');
  },
)

Selective rebuilds with id

Trigger only specific JuneBuilder widgets inside a shared state, leaving others untouched.

class FeedState extends JuneState {
  String header = 'Latest';
  List<Post> posts = [];

  void updateHeader(String value) {
    header = value;
    setState('header');          // only rebuilds builders with id: 'header'
  }

  void refreshPosts(List<Post> fresh) {
    posts = fresh;
    setState('posts');           // only rebuilds builders with id: 'posts'
  }
}

// Rebuilds only when 'header' setState is called
JuneBuilder(
  () => FeedState(),
  id: 'header',
  builder: (s) => Text(s.header),
)

// Rebuilds only when 'posts' setState is called
JuneBuilder(
  () => FeedState(),
  id: 'posts',
  builder: (s) => PostList(posts: s.posts),
)

Core API

tag vs id — when to use which

Migration

0.8.x → 1.0.0

The factory function is now passed as a closure rather than an evaluated instance:

// Before (0.8.x)
June.getState(CounterVM());

// After (1.0.0+)
June.getState(() => CounterVM());

Community

Questions, ideas, or just want to say hi?

Acknowledgements

June was shaped by the best ideas in the Flutter ecosystem. Gratitude to the teams and communities behind Provider, GetX, Bloc, and Riverpod, and to Svelte for proving that less really is more.