Flutter Event Limiter 🛡️ #

The production-ready event management system for Flutter.

Handle Throttling (anti-spam) and Debouncing (search APIs) with built-in safety against race conditions, memory leaks, and "setState after dispose" crashes.

Why this package? Most libraries require you to manually manage Timer disposal and mounted checks. We handle that automatically. Plus, we give you built-in loading states and work with ANY widget.

⚡ The 30-Second Demo #

The Old Way (Manual & Risky) #

15+ lines. Easy to forget dispose or mounted checks.

// ❌ Boilerplate & Error Prone
Timer? _timer;
bool _loading = false;

void onSearch(String text) {
  _timer?.cancel();
  _timer = Timer(Duration(milliseconds: 300), () async {
    setState(() => _loading = true);
    try {
      final result = await api.search(text);
      if (!mounted) return; // Must remember this!
      setState(() => _result = result);
    } finally {
      if (mounted) setState(() => _loading = false);
    }
  });
}

@override
void dispose() {
  _timer?.cancel(); // Must remember this too!
  super.dispose();
}

The New Way (Safe & Clean) #

3 lines. Auto-dispose. Auto-mounted check. Auto-loading state.

// ✅ Clean & Safe
AsyncDebouncedTextController(
  onChanged: (text) async => await api.search(text),
  onSuccess: (result) => setState(() => _result = result),
  onLoadingChanged: (loading) => setState(() => _loading = loading), // ✨ Magic!
)

✨ Key Features #

Feature	Description
🧩 Universal Builders	Use with ANY widget (Material, Cupertino, Custom UI). Not locked to specific buttons/textfields.
🛡️ Auto-Safety	Automatically checks `mounted` before callbacks. Automatically disposes timers.
⏳ Loading State	`isLoading` state is provided automatically. No need to create boolean flags.
🏁 Race Condition Fix	Automatically cancels previous async operations when a new one starts (Essential for Search).
📉 Zero Boilerplate	Reduces code by ~80% compared to manual implementation.

🚀 Usage Examples #

1. Prevent Button Double-Clicks (Throttle) #

Stop users from accidentally spamming payment buttons or API calls.

ThrottledInkWell(
  onTap: () => submitOrder(), // 👈 Only runs once per 500ms
  child: Text("Submit Order"),
)

// OR use with ANY widget:
ThrottledBuilder(
  builder: (context, throttle) {
    return CupertinoButton(
      onPressed: throttle(() => submitOrder()),
      child: Text("Submit"),
    );
  },
)

2. Smart Search Bar (Async Debounce) #

Waits for the user to stop typing. Automatically cancels old network requests to prevent wrong results.

AsyncDebouncedTextController(
  duration: Duration(milliseconds: 300),
  onChanged: (text) async => await api.search(text),

  // ✅ Only called if widget is mounted AND it's the latest result
  onSuccess: (products) => setState(() => _products = products),

  // ✅ Auto-manage loading spinner
  onLoadingChanged: (isLoading) => setState(() => _loading = isLoading),
)

3. Form Submission with Loading UI #

Disable the button and show a spinner while the async task runs.

AsyncThrottledCallbackBuilder(
  onPressed: () async => await uploadFile(),
  builder: (context, callback, isLoading) {
    return ElevatedButton(
      // Auto-disable button when loading
      onPressed: isLoading ? null : callback,
      child: isLoading
          ? CircularProgressIndicator()
          : Text("Upload"),
    );
  },
)

📊 Feature Comparison #

How flutter_event_limiter improves upon common patterns:

Feature	Raw Utility Libs	Stream Libs (Rx)	Hard-Coded Widget Libs	flutter_event_limiter
Approach	Manual	Reactive	Fixed Widgets	Builder Pattern
Works with Any Widget	❌	❌	❌	✅
Auto Mounted Check	❌	❌	❌	✅
Auto Loading State	❌	❌	❌	✅
Prevents Race Conditions	❌	✅	⚠️	✅
Setup Difficulty	Medium	Hard	Easy	Easy

Note: While libraries like RxDart are powerful for complex stream transformations, flutter_event_limiter is optimized specifically for UI event handling with zero setup.

🎨 Universal Builder Pattern #

The Power of Flexibility: Unlike libraries that lock you into specific widgets, our builder pattern works with everything.

Example 1: Custom FAB with Throttle #

ThrottledBuilder(
  duration: Duration(seconds: 1),
  builder: (context, throttle) {
    return FloatingActionButton(
      onPressed: throttle(() => saveData()),
      child: Icon(Icons.save),
    );
  },
)

Example 2: Cupertino Button with Debounce #

DebouncedBuilder(
  duration: Duration(milliseconds: 500),
  builder: (context, debounce) {
    return CupertinoButton(
      onPressed: debounce(() => updateSettings()),
      child: Text("Save"),
    );
  },
)

Example 3: Custom Slider with Debounce #

DebouncedBuilder(
  builder: (context, debounce) {
    return Slider(
      value: _volume,
      onChanged: (value) => debounce(() {
        setState(() => _volume = value);
        api.updateVolume(value);
      }),
    );
  },
)

Why this matters: Works with Material, Cupertino, Custom Widgets, or any third-party UI library.

📚 Complete Widget Reference #

🛡️ Throttling (Anti-Spam for Buttons) #

Executes immediately, then blocks for duration.

Widget	Use Case
`ThrottledInkWell`	Buttons with Material ripple effect
`ThrottledTapWidget`	Buttons without ripple
`ThrottledBuilder`	Universal - Works with ANY widget
`AsyncThrottledCallbackBuilder`	Async operations with auto loading state
`AsyncThrottledCallback`	Async operations (manual mounted check)
`Throttler`	Direct class usage (advanced)

When to use: Button clicks, form submissions, prevent spam clicks

⏱️ Debouncing (Search, Auto-save) #

Waits for pause, then executes.

Widget	Use Case
`DebouncedTextController`	Basic text input debouncing
`AsyncDebouncedTextController`	Search API with auto-cancel & loading state
`DebouncedBuilder`	Universal - Works with ANY widget
`AsyncDebouncedCallbackBuilder`	Async with loading state
`Debouncer`	Direct class usage (advanced)

When to use: Search input, auto-save, real-time validation

🎮 High-Frequency Events #

Widget	Use Case
`HighFrequencyThrottler`	Scroll, mouse move, resize (60fps max, zero Timer overhead)

💼 Real-World Scenarios #

🛒 E-Commerce: Prevent Double Checkout #

Problem: User clicks "Place Order" twice during slow network → Payment charged twice.

ThrottledInkWell(
  onTap: () async => await placeOrder(),
  child: Container(
    padding: EdgeInsets.all(16),
    color: Colors.green,
    child: Text("Place Order - \$199.99"),
  ),
)
// ✅ Second click ignored for 500ms - No duplicate orders

🔍 Search with Race Condition Prevention #

Problem: User types "abc", API for "a" returns after "abc" → Wrong results displayed.

AsyncDebouncedTextController(
  duration: Duration(milliseconds: 300),
  onChanged: (text) async => await searchProducts(text),
  onSuccess: (products) => setState(() => _products = products),
  onLoadingChanged: (loading) => setState(() => _searching = loading),
)
// ✅ Old API calls auto-cancelled
// ✅ Only latest result displayed

📝 Form with Auto Loading State #

Problem: No feedback during submission → User clicks again → Duplicate submit.

AsyncThrottledCallbackBuilder(
  onPressed: () async {
    await validateForm();
    await submitForm();
    if (!context.mounted) return;
    Navigator.pop(context);
  },
  onError: (error, stack) => showSnackBar('Failed: $error'),
  builder: (context, callback, isLoading) {
    return ElevatedButton(
      onPressed: isLoading ? null : callback,
      child: isLoading ? CircularProgressIndicator() : Text("Submit"),
    );
  },
)
// ✅ Button auto-disabled during submit
// ✅ Loading indicator auto-managed

💬 Chat App: Prevent Message Spam #

Problem: User presses Enter rapidly → Sends duplicate messages.

ThrottledBuilder(
  duration: Duration(seconds: 1),
  builder: (context, throttle) {
    return IconButton(
      onPressed: throttle(() => sendMessage(_controller.text)),
      icon: Icon(Icons.send),
    );
  },
)
// ✅ Max 1 message per second

🎓 Throttle vs Debounce: Which One? #

Throttle (Anti-Spam) #

Fires immediately, then ignores clicks for a duration.

User clicks: ▼     ▼   ▼▼▼       ▼
Executes:    ✓     X   X X       ✓
             |<-500ms->|         |<-500ms->|

Use for: Buttons, Submits, Refresh actions

Debounce (Delay) #

Waits for a pause in action, then fires.

User types:  a  b  c  d ... (pause) ... e  f  g
Executes:                   ✓                   ✓
             |<--300ms wait-->|     |<--300ms wait-->|

Use for: Search bars, Auto-save, Slider values

AsyncDebouncer (Debounce + Auto-Cancel) #

Waits for pause + Cancels previous async operations.

User types:  a    b    c  (API starts) ... d
API calls:   X    X    ▼ (running...)   X (cancelled)
Result used:                            ✓ (only 'd')

Use for: Search APIs, autocomplete, async validation

🔄 Migration from Other Libraries #

From `easy_debounce` #

Why migrate? Stop managing string IDs manually. Stop worrying about memory leaks.

// Before: Manual ID management, easy to forget dispose
import 'package:easy_debounce/easy_debounce.dart';

void onSearch(String text) {
  EasyDebounce.debounce(
    'search-tag', // ❌ Manage ID manually
    Duration(milliseconds: 300),
    () async {
      final result = await api.search(text);
      if (!mounted) return; // ❌ Easy to forget
      setState(() => _results = result);
    },
  );
}

@override
void dispose() {
  EasyDebounce.cancel('search-tag'); // ❌ Easy to forget
  super.dispose();
}

// After: Auto-everything, 70% less code
AsyncDebouncedTextController(
  onChanged: (text) async => await api.search(text),
  onSuccess: (results) => setState(() => _results = results),
)
// ✅ Auto-dispose, auto mounted check, no ID management

Benefits:

✅ No string ID management
✅ Auto-dispose (zero memory leaks)
✅ Built-in loading state
✅ Auto race condition prevention

From `flutter_smart_debouncer` #

Why migrate? Stop being locked into hard-coded widgets. Use ANY widget you want.

// Before: Locked to specific widget
SmartDebouncerButton(
  onPressed: () => submit(),
  child: Text("Submit"),
)
// ❌ What if you need CupertinoButton? FloatingActionButton? Custom widget?

// After: Universal builder - Use ANY widget
ThrottledBuilder(
  builder: (context, throttle) {
    return CupertinoButton( // Or FloatingActionButton, Custom, etc.
      onPressed: throttle(() => submit()),
      child: Text("Submit"),
    );
  },
)

Benefits:

✅ Works with ANY widget (Material, Cupertino, Custom)
✅ Not locked into specific UI components
✅ More flexible and future-proof
✅ Built-in loading state

From `rxdart` #

Why migrate? For simple UI events, you don't need Stream complexity.

// Before: 15+ lines with Stream/BehaviorSubject
final _searchController = BehaviorSubject<String>();

@override
void initState() {
  super.initState();
  _searchController.stream
    .debounceTime(Duration(milliseconds: 300))
    .listen((text) async {
      final result = await api.search(text);
      if (!mounted) return;
      setState(() => _result = result);
    });
}

@override
void dispose() {
  _searchController.close();
  super.dispose();
}

// After: 3 lines, no Stream knowledge needed
AsyncDebouncedTextController(
  onChanged: (text) async => await api.search(text),
  onSuccess: (result) => setState(() => _result = result),
)

Benefits:

✅ 80% less boilerplate
✅ No need to learn Streams/Subjects/Operators
✅ Auto mounted check (zero crashes)
✅ Flutter-first design (optimized for UI events)

When to still use RxDart:

Complex reactive state management across multiple screens
Need advanced operators (combineLatest, switchMap, etc.)
Building reactive architecture (BLoC pattern)

🔧 Advanced Features #

Custom Durations #

ThrottledInkWell(
  duration: Duration(seconds: 1), // Configurable
  onTap: () => submit(),
  child: Text('Submit'),
)

Reset Throttle Manually #

final throttler = Throttler();

InkWell(
  onTap: throttler.wrap(() => handleTap()),
  child: Text('Tap me'),
)

// Reset to allow immediate next call
throttler.reset();

// Check current state
if (throttler.isThrottled) {
  print('Currently blocked');
}

Flush Debouncer (Execute Immediately) #

final controller = DebouncedTextController(
  onChanged: (text) => search(text),
);

// User presses Enter → Execute immediately without waiting
onSubmit() {
  controller.flush(); // Cancels timer, executes now
}

Manual Cancel #

final debouncer = AsyncDebouncer();

// Start debounced operation
debouncer.run(() async => await api.call());

// Cancel all pending operations
debouncer.cancel();

⚠️ Common Pitfalls #

1. Forgetting Mounted Check with Builder Widgets #

// ❌ BAD - Will crash if widget unmounts during async operation
AsyncDebouncedBuilder(
  builder: (context, debounce) {
    return TextField(
      onChanged: (text) => debounce(() async {
        final result = await api.search(text);
        setState(() => _result = result); // ❌ Crash if unmounted!
      }),
    );
  },
)

// ✅ GOOD - Always check mounted
AsyncDebouncedBuilder(
  builder: (context, debounce) {
    return TextField(
      onChanged: (text) => debounce(() async {
        final result = await api.search(text);
        if (!mounted) return; // ✅ Safe
        setState(() => _result = result);
      }),
    );
  },
)

// ✅ BETTER - Use CallbackBuilder for automatic mounted check
AsyncDebouncedCallbackBuilder(
  onChanged: (text) async => await api.search(text),
  onSuccess: (result) => setState(() => _result = result), // ✅ Auto-checks mounted
  builder: (context, callback, isLoading) => TextField(onChanged: callback),
)

2. Not Handling Null from AsyncDebouncer #

// ❌ BAD - Can crash if result is null (cancelled)
final result = await asyncDebouncer.run(() async => await api.call());
processResult(result); // ❌ Crash if cancelled

// ✅ GOOD - Check for cancellation
final result = await asyncDebouncer.run(() async => await api.call());
if (result == null) return; // Operation was cancelled
processResult(result); // ✅ Safe

3. Providing Both `controller` and `initialValue` #

// ❌ BAD - Will throw assertion error
DebouncedTextController(
  controller: myController,
  initialValue: "test", // ❌ Conflict!
  onChanged: (text) => search(text),
)

// ✅ GOOD - Use controller only
final controller = TextEditingController(text: "initial");
DebouncedTextController(
  controller: controller,
  onChanged: (text) => search(text),
)

// ✅ GOOD - Use initialValue only
DebouncedTextController(
  initialValue: "initial",
  onChanged: (text) => search(text),
)

❓ FAQ #

Q: Can I use this with GetX/Riverpod/Bloc? #

A: Yes! State-management agnostic.

// GetX
ThrottledInkWell(
  onTap: () => Get.find<MyController>().submit(),
  child: Text("Submit"),
)

// Riverpod
AsyncDebouncedTextController(
  onChanged: (text) async => await ref.read(searchProvider.notifier).search(text),
  onSuccess: (results) => /* update state */,
)

// Bloc
ThrottledBuilder(
  builder: (context, throttle) {
    return ElevatedButton(
      onPressed: throttle(() => context.read<MyBloc>().add(SubmitEvent())),
      child: Text("Submit"),
    );
  },
)

Q: How to test widgets using this library? #

testWidgets('throttle blocks rapid clicks', (tester) async {
  int clickCount = 0;

  await tester.pumpWidget(
    MaterialApp(
      home: ThrottledInkWell(
        duration: Duration(milliseconds: 500),
        onTap: () => clickCount++,
        child: Text('Tap'),
      ),
    ),
  );

  await tester.tap(find.text('Tap'));
  await tester.pump();
  expect(clickCount, 1);

  await tester.tap(find.text('Tap')); // Blocked
  await tester.pump();
  expect(clickCount, 1); // Still 1!

  await tester.pumpAndSettle(Duration(milliseconds: 500));

  await tester.tap(find.text('Tap')); // Works again
  await tester.pump();
  expect(clickCount, 2);
});

Q: Performance overhead? #

A: Near-zero!

Throttle/Debounce: ~0.01ms per call
High-Frequency Throttler: ~0.001ms (100x faster, uses DateTime instead of Timer)
Memory: ~40 bytes per controller

🛠 Installation #

dependencies:
  flutter_event_limiter: ^1.0.0

Then run:

flutter pub get

Import:

import 'package:flutter_event_limiter/flutter_event_limiter.dart';

🤝 Contributing #

We welcome contributions! Please feel free to check the issues or submit a PR.

Bugs: Open an issue with a reproduction sample.
Features: Discuss new features in issues before implementing.

📄 License #

MIT License - See LICENSE file for details.

📮 Support #

📧 Issues: GitHub Issues
💬 Discussions: GitHub Discussions
⭐ Star this repo if you find it useful!

Made with ❤️ for the Flutter community

flutter_event_limiter 1.0.3 flutter_event_limiter: ^1.0.3 copied to clipboard

Metadata

Flutter Event Limiter 🛡️ #

⚡ The 30-Second Demo #

The Old Way (Manual & Risky) #

The New Way (Safe & Clean) #

✨ Key Features #

🚀 Usage Examples #

1. Prevent Button Double-Clicks (Throttle) #

2. Smart Search Bar (Async Debounce) #

3. Form Submission with Loading UI #

📊 Feature Comparison #

🎨 Universal Builder Pattern #

Example 1: Custom FAB with Throttle #

Example 2: Cupertino Button with Debounce #

Example 3: Custom Slider with Debounce #

📚 Complete Widget Reference #

🛡️ Throttling (Anti-Spam for Buttons) #

⏱️ Debouncing (Search, Auto-save) #

🎮 High-Frequency Events #

💼 Real-World Scenarios #

🛒 E-Commerce: Prevent Double Checkout #

🔍 Search with Race Condition Prevention #

📝 Form with Auto Loading State #

💬 Chat App: Prevent Message Spam #

🎓 Throttle vs Debounce: Which One? #

Throttle (Anti-Spam) #

Debounce (Delay) #

AsyncDebouncer (Debounce + Auto-Cancel) #

🔄 Migration from Other Libraries #

From easy_debounce #

From flutter_smart_debouncer #

From rxdart #

🔧 Advanced Features #

Custom Durations #

Reset Throttle Manually #

Flush Debouncer (Execute Immediately) #

Manual Cancel #

⚠️ Common Pitfalls #

1. Forgetting Mounted Check with Builder Widgets #

2. Not Handling Null from AsyncDebouncer #

3. Providing Both controller and initialValue #

❓ FAQ #

Q: Can I use this with GetX/Riverpod/Bloc? #

Q: How to test widgets using this library? #

Q: Performance overhead? #

🛠 Installation #

🤝 Contributing #

📄 License #

📮 Support #

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flutter_event_limiter 1.0.3
flutter_event_limiter: ^1.0.3 copied to clipboard

From `easy_debounce` #

From `flutter_smart_debouncer` #

From `rxdart` #

3. Providing Both `controller` and `initialValue` #