signals library

Classes

AsyncData<T>

State for an AsyncState with a value

AsyncError<T>

State for an AsyncState with an error

AsyncLoading<T>

State for an AsyncState with a loading state

AsyncSignal<T>

The signal function creates a new signal. A signal is a container for a value that can change over time. You can read a signal's value or subscribe to value updates by accessing its .value property.

AsyncState<T>

AsyncState is class commonly used with Future/Stream signals to represent the states the signal can be in.

ChangeStackSignal<T>

Change stack signal that can be used to call undo/redo on a value.

Computed<T>

Data is often derived from other pieces of existing data. The computed function lets you combine the values of multiple signals into a new signal that can be reacted to, or even used by additional computeds. When the signals accessed from within a computed callback change, the computed callback is re-executed and its new return value becomes the computed signal's value.

Connect<T, S extends T>

The idea for connect comes from Anguar Signals with RxJS:

DevToolsSignalsObserver

Signals DevTools observer

Effect

The effect function is the last piece that makes everything reactive. When you access a signal inside its callback function, that signal and every dependency of said signal will be activated and subscribed to. In that regard it is very similar to computed(fn). By default all updates are lazy, so nothing will update until you access a signal inside effect.

FutureSignal<T>

Future signals can be created by extension or method.

IterableSignal<E>

A Signal that holds a Iterable.

ListSignal<E>

A Signal that holds a List.

LoggingSignalsObserver

Logs all signals and computed changes to the console.

MapSignal<K, V>

A Signal that holds a Map.

QueueSignal<T>

A Signal that holds a Queue.

ReadonlySignal<T>

Read only signals can just retrieve a value but not update or cause mutations

SetSignal<E>

A Signal that holds a Set.

Signal<T>

The signal function creates a new signal. A signal is a container for a value that can change over time. You can read a signal's value or subscribe to value updates by accessing its .value property.

SignalContainer<T, Arg, S extends ReadonlySignal<T>>

Signal container used to create signals based on args

SignalListenable

Signal listenable that both Computed and Effect extend

SignalsObserver

You can observe all signal values in the dart application by providing an implementation of SignalsObserver:

StreamSignal<T>

Stream signals can be created by extension or method.

TimerSignal

Emit recurring TimerSignalEvent aka AsyncSignal

WrappedReadonlySignal<T, S extends ReadonlySignal<T>>

Wrap a ReadonlySignal and implement the same API

WrappedSignal<T>

Wrap a Signal and implement the same API

Mixins

ValueSignalMixin<T>

Value Signal mixin (list/map/set)

Extensions

ReadonlySignalUtils on ReadonlySignal<T>

Signal extensions

SignalFutureUtils on Future<T>

Extension on future to provide helpful methods for signals

SignalIterableUtils on Iterable<T>

Extension on future to provide helpful methods for signals

SignalListUtils on List<T>

Extension on future to provide helpful methods for signals

SignalMapUtils on Map<K, V>

Extension on future to provide helpful methods for signals

SignalObjectUtils on T

Extension on Object to provide helpful methods for signals

SignalOptionalObjectUtils on T?

Extension on nullable Object to provide helpful methods for signals

SignalQueueUtils on Queue<T>

Extension on future to provide helpful methods for signals

SignalsCallbackFunctionUtils on SignalsCallbackFunction<T>

A callback function that can be used to update a signal.

SignalSetUtils on Set<T>

Extension on future to provide helpful methods for signals

SignalStreamUtils on Stream<T>

Extension on stream to provide helpful methods for signals

TimerSignalDurationUtils on Duration

Expose Duration as a TimerSignal

Properties

signalsDevToolsEnabled ↔ bool

Check if the signals devtools are enabled

getter/setter pair

Functions

asyncSignal<T>(AsyncState<T> value, {String? debugLabel, bool autoDispose = false}) → AsyncSignal<T>

The signal function creates a new signal. A signal is a container for a value that can change over time. You can read a signal's value or subscribe to value updates by accessing its .value property.

batch<T>(BatchCallback<T> fn) → T

The batch function allows you to combine multiple signal writes into one single update that is triggered at the end when the callback completes.

changeStack<T>(T value, {String? debugLabel, int? limit, bool autoDispose = false}) → ChangeStackSignal<T>

Change stack signal that can be used to call undo/redo on a value.

computed<T>(ComputedCallback<T> compute, {String? debugLabel, bool autoDispose = false}) → Computed<T>

Data is often derived from other pieces of existing data. The computed function lets you combine the values of multiple signals into a new signal that can be reacted to, or even used by additional computeds. When the signals accessed from within a computed callback change, the computed callback is re-executed and its new return value becomes the computed signal's value.

computedAsync<T>(Future<T> callback(), {T? initialValue, String? debugLabel, bool autoDispose = false, List<ReadonlySignal> dependencies = const [], bool lazy = true}) → FutureSignal<T>

Async Computed is syntax sugar around FutureSignal.

computedFrom<T, A>(List<ReadonlySignal<A>> signals, Future<T> callback(List<A> args), {T? initialValue, String? debugLabel, bool autoDispose = false, bool lazy = true}) → FutureSignal<T>

Async Computed is syntax sugar around FutureSignal.

connect<T, S extends T>(Signal<T> signal, [Stream<S>? stream]) → Connect<T, S>

The idea for connect comes from Anguar Signals with RxJS:

disableSignalsDevTools() → void

Disable the devtools

effect(EffectCallback compute, {String? debugLabel, EffectCallback? onDispose}) → EffectCleanup

The effect function is the last piece that makes everything reactive. When you access a signal inside its callback function, that signal and every dependency of said signal will be activated and subscribed to. In that regard it is very similar to computed(fn). By default all updates are lazy, so nothing will update until you access a signal inside effect.

futureSignal<T>(Future<T> callback(), {T? initialValue, String? debugLabel, List<ReadonlySignal> dependencies = const [], bool lazy = true, bool autoDispose = false}) → FutureSignal<T>

Future signals can be created by extension or method.

iterableSignal<T>(Iterable<T> iterable, {String? debugLabel, bool autoDispose = false}) → IterableSignal<T>

Create an IterableSignal from Iterable

lazySignal<T>({String? debugLabel, bool autoDispose = false}) → Signal<T>

Lazy signal that can be created with type T that the value will be assigned later.

listSignal<T>(List<T> list, {String? debugLabel, bool autoDispose = false}) → ListSignal<T>

Create an ListSignal from List

mapSignal<K, V>(Map<K, V> map, {String? debugLabel, bool autoDispose = false}) → MapSignal<K, V>

Create an MapSignal from Map

queueSignal<T>(Queue<T> list, {String? debugLabel, bool autoDispose = false}) → QueueSignal<T>

Create an QueueSignal from Queue

readonlySignalContainer<T, Arg>(ReadonlySignal<T> create(Arg), {bool cache = false}) → SignalContainer<T, Arg, ReadonlySignal<T>>

Create a signal container used to instance signals based on args

reloadSignalsDevTools() → void

Reload the devtools

setSignal<T>(Set<T> list, {String? debugLabel, bool autoDispose = false}) → SetSignal<T>

Create an SetSignal from Set

signal<T>(T value, {String? debugLabel, bool autoDispose = false}) → Signal<T>

The signal function creates a new signal. A signal is a container for a value that can change over time. You can read a signal's value or subscribe to value updates by accessing its .value property.

signalContainer<T, Arg>(Signal<T> create(Arg), {bool cache = false}) → SignalContainer<T, Arg, Signal<T>>

Create a signal container used to instance signals based on args

streamSignal<T>(Stream<T> callback(), {T? initialValue, String? debugLabel, List<ReadonlySignal> dependencies = const [], void onDone()?, bool? cancelOnError, bool lazy = true, bool autoDispose = false}) → StreamSignal<T>

Stream signals can be created by extension or method.

timerSignal(Duration every, {String debugLabel = 'Timer', bool? cancelOnError, bool autoDispose = false}) → TimerSignal

Create a TimerSignal

untracked<T>(UntrackedCallback<T> fn) → T

In case when you're receiving a callback that can read some signals, but you don't want to subscribe to them, you can use untracked to prevent any subscriptions from happening.

valueSignal<T>(T value, {String? debugLabel, bool autoDispose = false}) → ValueSignal<T>

Wrapper signal for a reference to an object

Typedefs

AsyncDataBuilder<E, T> = E Function(T value)

Value builder for AsyncState

AsyncErrorBuilder<E> = Function

Error builder for AsyncState

AsyncStateBuilder<E> = E Function()

Generic builder for AsyncState

BatchCallback<T> = T Function()

A callback that is executed inside a batch.

ComputedCallback<T> = T Function()

A callback that is executed inside a computed.

EffectCallback = dynamic Function()

Function called when signals in the callback change

EffectCleanup = void Function()

Clean up function to stop subscriptions from updating the callback

SignalChange<T> = ({T previousValue, T value})

Signal change that contains a snapshot of the previous value and next value

SignalsCallbackFunction<T> = dynamic Function(dynamic (T value))

A callback function that can be used to update a signal.

TimerSignalEvent = ({int iteration, int millis})

Time event to react to

UntrackedCallback<T> = T Function()

A callback that is executed inside a computed.

ValueSignal<T> = Signal<T>

Alias for Signal

Exceptions / Errors

EffectCycleDetectionError

Cycle detection usually means you have updated a signal inside an effect and are reading by value.

LazySignalInitializationError

Lazy signal must value value set before it is read

SignalsError

Signal usage error

SignalsReadAfterDisposeError

Error to throw if a signal is read after it is disposed

SignalsWriteAfterDisposeError

Error to throw if a signal is written to after it is disposed