PersistSignal<T> class abstract interface

Signal that persists its value to external storage.

Automatically saves value changes to storage. Supports sync/async reads, lazy loading, and write throttling. Uses a 2-element write queue.

Initialization:

• Sync signals: initialized immediately (or on first access if lazy)
• Async signals: must call ensure or getEnsured before writing

Example (sync):

final theme = PersistSignal.sync(
  read: () => prefs.getString('theme') ?? 'light',
  write: (value) => prefs.setString('theme', value),
);
theme.value = 'dark'; // Auto-saved

Example (async):

final theme = PersistSignal.async(
  read: () async => await prefs.getString('theme') ?? 'light',
  write: (value) => prefs.setString('theme', value),
  initialValue: () => 'light',
);
await theme.ensure(); // Wait for init
theme.value = 'dark'; // Auto-saved

Implemented types

• Signal<T>

Implementers

• AsyncPersistSignalImpl
• SyncPersistSignalImpl

Available extensions

• JoltSignalExtension
• JoltUtilsReadableExtension
• JoltUtilsStreamExtension
• JoltUtilsUntilExtension
• JoltUtilsWritableExtension

Constructors

PersistSignal.async({required Future<T> read(), required FutureOr<void> write(T value), T initialValue()?, bool lazy, Duration? throttle, JoltDebugFn? onDebug})

Creates an asynchronous persistent signal.

factory

PersistSignal.lazyAsync({required Future<T> read(), required FutureOr<void> write(T value), T initialValue()?, Duration? throttle, JoltDebugFn? onDebug})

Creates a lazy asynchronous persistent signal.

factory

PersistSignal.lazySync({required T read(), required FutureOr<void> write(T value), Duration? throttle, JoltDebugFn? onDebug})

Creates a lazy synchronous persistent signal.

factory

PersistSignal.sync({required T read(), required FutureOr<void> write(T value), bool lazy, Duration? throttle, JoltDebugFn? onDebug})

Creates a synchronous persistent signal.

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

isDisposed → bool

Whether this node has been disposed.

no setter, inherited

isInitialized → bool

Whether initialized from storage.

no setter

peek → T

Gets the current value without establishing a reactive dependency.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

stream → Stream<T>

Available on Readable<T>, provided by the JoltUtilsStreamExtension extension

Converts this reactive value to a broadcast stream.

no setter

value ↔ T

Gets the current value and establishes a reactive dependency.

getter/setter pair, inherited

Methods

call() → T

Available on Readable<T>, provided by the JoltUtilsReadableExtension extension

Gets the current value (callable syntax).

derived<U>(U computed(T value)) → Computed<U>

Available on Readable<T>, provided by the JoltUtilsReadableExtension extension

Creates a computed value derived from this readable.

dispose() → void

Disposes this node and cleans up resources.

inherited

ensure([FutureOr<void> fn(T value)?]) → Future<void>

Ensures initialization, optionally running a function.

ensureWrite() → Future<void>

Waits for all pending writes to complete.

get() → T

Available on Readable<T>, provided by the JoltUtilsReadableExtension extension

Gets the current value.

getEnsured() → Future<T>

Gets value, ensuring initialization is complete.

listen(void onData(T event)?, {Function? onError, void onDone()?, bool? cancelOnError, bool immediately = false}) → StreamSubscription<T>

Available on Readable<T>, provided by the JoltUtilsStreamExtension extension

Listens to changes in this reactive value.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

notify() → void

Triggers a change notification without modifying the value.

inherited

readonly() → ReadonlySignal<T>

Available on Signal<T>, provided by the JoltSignalExtension extension

Returns a read-only view of this signal.

set(T value) → T

Available on Writable<T>, provided by the JoltUtilsWritableExtension extension

Sets the value.

toString() → String

A string representation of this object.

inherited

until(bool predicate(T value)) → Future<T>

Available on ReadableNode<T>, provided by the JoltUtilsUntilExtension extension

Waits until the value satisfies a condition.

untilWhen<U>(U predicate) → Future<T>

Available on ReadableNode<T>, provided by the JoltUtilsUntilExtension extension

Waits until the reactive value equals a specific value.

update(T updater(T value)) → T

Available on Writable<T>, provided by the JoltUtilsWritableExtension extension

Updates the value using an updater function based on the current value.

Operators

operator ==(Object other) → bool

The equality operator.

inherited