better_value_notifier

Typed ValueNotifier wrappers, reactive extensions, and small builder widgets for Flutter.

better_value_notifier is designed for apps that want the simplicity of ValueNotifier, but with:

• typed notifier classes for common value kinds
• collection-aware mutation boundaries
• derived listenables and stream bridging
• lightweight widget helpers for rebuilding from listenables

Features

• Primitive notifiers like BoolNotifier, IntNotifier, DoubleNotifier, NumNotifier, StringNotifier, DateTimeNotifier, DurationNotifier, UriNotifier, ThemeModeNotifier, and BrightnessNotifier
• Collection notifiers like ListNotifier, MapNotifier, and SetNotifier
• Reactive helpers like map, select, distinct, and combine
• Stream bridging through StreamValueNotifier and toValueNotifier(...)
• Widget helpers like ListenablesBuilder plus builder(...) extensions on Listenable and ValueListenable

Install

dependencies:
  better_value_notifier: ^1.0.0

Quick start

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

final enabled = false.notifier;
final counter = 0.notifier;
final tags = <String>['flutter', 'dart'].notifier;

final isEven = counter.map((value) => value.isEven);

Basic usage

Primitive values

final enabled = true.notifier;
enabled.toggle();
enabled.setFalse();

final themeMode = ThemeMode.system.notifier;
themeMode.setDark();

Collection values

final items = <String>['a', 'b'].notifier;

items.add('c');

items.mutate((list) {
  list.add('d');
  list.remove('a');
});

Derived values

final firstName = ValueNotifier('Omar');
final lastName = ValueNotifier('Hanafy');

final fullName = firstName.combine(
  lastName,
  (first, last) => '$first $last',
);

Stream bridge

final notifier = stream.toValueNotifier(
  initialValue,
  onDone: (latestValue) {
    debugPrint('done with $latestValue');
  },
);

Widget helpers

ListenablesBuilder(
  listenables: [firstName, lastName],
  builder: (context) {
    return Text('${firstName.value} ${lastName.value}');
  },
);

Notification model

The package follows a clear contract for when listeners are notified.

1. Explicit mutators notify

Collection writes like add, remove, []=, clear, updateAll, sort, and retainWhere notify automatically.

2. mutate(...) is the explicit in-place mutation boundary

Use mutate(...) when you want to perform multiple collection changes or nested changes and notify exactly once at the end.

users.mutate((list) {
  list.add(user);
  list.sort((a, b) => a.name.compareTo(b.name));
});

3. Direct deep mutation through .value is not auto-detected

If you mutate an inner object directly, call refresh(), update(...), replace(...), or mutate(...) afterward.

users.value.first.name = 'Updated';
users.refresh();

4. Eager callback-based collection methods refresh after execution

Methods like forEach, fold, reduce, every, any, firstWhere, lastWhere, singleWhere, and list index-search helpers act as notification boundaries for collection notifiers.

5. Lazy adapters stay pure

Methods like where, map, expand, takeWhile, and skipWhile do not notify when created.

6. Immutable-style wrappers keep read methods pure

Wrappers like StringNotifier, UriNotifier, DateTimeNotifier, DurationNotifier, and ColorNotifier do not notify for read or transform helpers that return new values.

Public API

• better_value_notifier.dart Full package export
• extensions.dart Reactive and convenience extensions
• notifier_classes.dart Typed notifier classes
• widgets.dart Widget helpers

Notes

• Collection notifiers own their internal collection state instead of aliasing the source collection passed into the constructor.
• refresh() always notifies, even if the outer value is unchanged.
• update(...) force-notifies when the incoming value is effectively unchanged.
• StreamValueNotifier should be disposed when no longer needed so the stream subscription is cancelled.