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rodydavis/signals.dart ★9999⑂99

Type: SignalContainer

API reference and details for SignalContainer from signals.dart.

SignalContainer#

Kind: class & function  |  Package: package:signals_core

Class: SignalContainer#

Signal container used to create signals based on args

final container = readonlySignalContainer<Cache, String>((e) {
  return signal(Cache(e));
});

final cacheA = container('cache-a');
final cacheB = container('cache-b');
final cacheC = container('cache-c');

Example of settings and SharedPreferences:

class Settings {
  final SharedPreferences prefs;
  EffectCleanup? _cleanup;

  Settings(this.prefs) {
    _cleanup = effect(() {
      for (final entry in setting.store.entries) {
        final value = entry.value.peek();
        if (prefs.getString(entry.key.$1) != value) {
          prefs.setString(entry.key.$1, value).ignore();
        }
      }
    });
  }

  late final setting = signalContainer<String, (String, String)>(
    (val) => signal(prefs.getString(val.$1) ?? val.$2),
    cache: true,
  );

  Signal<String> get darkMode => setting(('dark-mode', 'false'));

  void dispose() {
    _cleanup?.call();
    setting.dispose();
  }
}

void main() {
 // Load or find instance
 late final SharedPreferences prefs = ...;

 // Create settings
 final settings = Settings(prefs);

 // Get value
 print('dark mode: ${settings.darkMode}');

 // Update value
 settings.darkMode.value = 'true';
}

Members of SignalContainer#

Member Type Signature Description
cache field dart bool cache If true then signals will be cached when created
onEvict field dart void Function(Arg key, S signal)? onEvict Optional callback when a signal is removed/evicted from the cache
store field dart store Store of created signals (if cache is true)
SignalContainer constructor dart SignalContainer(this._create, {this.cache = false, this.onEvict}) Signal container used to create multiple signals via args
call method dart S call(Arg arg) Create the signal with the given args
remove method dart S? remove(Arg arg) Remove a signal from the cache
containsKey method dart bool containsKey(Arg arg) Check if signal is currently stored in the cache
clear method dart void clear() Clear the cache
dispose method dart void dispose() Dispose of all created signals
length method dart int length Returns the number of cached signals.
isEmpty method dart bool isEmpty Returns true if the cache is empty.
isNotEmpty method dart bool isNotEmpty Returns true if the cache is not empty.
keys method dart Iterable keys Returns all currently cached keys.
values method dart Iterable values Returns all currently cached signals.
entries method dart Iterable<MapEntry<Arg, S>> entries Returns all currently cached entries.
lookup method dart S? lookup(Arg arg) Retrieve the cached signal for arg if it exists, without creating a new one if it is missing.
removeWhere method dart void removeWhere(bool Function(Arg key, S signal) test) Filter and remove matching cached signals.

Function: signalContainer# 

SignalContainer<T, Arg, Signal<T>> signalContainer(Signal<T> Function(Arg) create, {bool cache = false, void Function(Arg key, Signal<T> signal)? onEvict})

Create a signal container used to instance signals based on args

final container = signalContainer<Cache, String>((e) {
  return signal(Cache(e));
});

final cacheA = container('cache-a');
final cacheB = container('cache-b');
final cacheC = container('cache-c');

cacheA.value = 'a';
cacheB.value = 'b';
cacheC.value = 'c';

References#

The SignalContainer type is referenced and used in the following pages: