SignalSelector<T, S> class

============================================================================ SIGNAL SELECTOR (GRANULAR REBUILDS)

Select a part of a signal's value for granular rebuilds.

SignalSelector creates a derived signal that only updates when the selected part of the value changes.

Basic Usage

class User {
  final String name;
  final int age;
  User(this.name, this.age);
}

final user = Signal(User('Alice', 25));

// Only emits when name changes
final nameSignal = SignalSelector(user, (u) => u.name);

nameSignal.addListener(() {
  print('Name changed: ${nameSignal.value}');
});
Inheritance
Available extensions

Constructors

SignalSelector(Signal<T> source, S selector(T value), {String? debugLabel})

Properties

debugLabel → String?
Debug label for identification in DevTools.
finalinherited
equals → bool Function(S a, S b)?
Custom equality function to determine if value has changed.
finalinherited
guard → S Function(S current, S next)?
Value guard/transformer called before setting a new value.
finalinherited
hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
Whether this atom has any listeners.
no setterinherited
initialValue → S
The initial value of the atom.
no setterinherited
isDisposed → bool
Whether this atom has been disposed.
no setterinherited
onCancel → VoidCallback?
Callback invoked when the last listener unsubscribes.
finalinherited
onListen → VoidCallback?
Callback invoked when the first listener subscribes.
finalinherited
previousValue → S?
The previous value of the atom (before the last change).
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
selector → S Function(T value)
final
source → Signal<T>
final
stream → Stream<S>
A broadcast stream of value changes.
no setterinherited
val → S
Short alias for the current value.
no setteroverride
value ↔ S
When cold (no listeners), always recompute from source.
getter/setter pairinherited-setteroverride-getter

Methods

add(num amount) → void

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

Add amount to numeric signal and emit. Alias for increment.
addListener(VoidCallback listener) → AtomListener
Adds a listener to be called when the value changes.
inherited
animated({required Widget to(BuildContext context, T value), Duration duration = const Duration(milliseconds: 300), Curve curve = Curves.easeInOut, SlotEffect effect = SlotEffect.fade, DirectionalEffect? directionalEffect}) → Widget

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

Create an AnimatedSlot with elegant syntax.
bind(NeuronController parent) → T

Available on T, provided by the SignalBinding extension

Registers this notifier to be disposed with parent.
bouncy({required Widget to(BuildContext context, double animatedValue)}) → Widget

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

Create a bouncy spring animation.
debounce(Duration duration) → DebouncedSignal<T>

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

Create a debounced version of this signal.
debounced({required Widget to(BuildContext context, T value), Duration duration = const Duration(milliseconds: 300)}) → Widget

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

Create a debounced slot.
dec([num by = 1]) → void

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

Short alias for decrement. Decrements numeric signal by by (default 1).
decrement([num by = 1]) → void

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

Decrement numeric signal.
dispose() → void
Disposes the atom, removing all listeners.
override
distinct() → DistinctSignal<T>

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

Create a distinct version of this signal.
emit(S val) → void
Assigns a new value and notifies listeners if the value changed.
inherited
expandCollapseMorph({double size = 24, Color? color, IconMorphStyle style = IconMorphStyle.rotateScale}) → Widget

Available on Signal<bool>, provided by the BooleanMorphExtensions extension

Create an expand/collapse icon morph.
favoriteMorph({double size = 24, Color? activeColor, Color? inactiveColor, IconMorphStyle style = IconMorphStyle.scale}) → Widget

Available on Signal<bool>, provided by the BooleanMorphExtensions extension

Create a favorite toggle icon morph.
form({required Widget to(BuildContext context, T value, FormValidationResult validation, bool isFocused), String? validator(T value)?, FormAnimationEffect errorEffect = FormAnimationEffect.shake, FormAnimationEffect successEffect = FormAnimationEffect.pulse, Duration animationDuration = const Duration(milliseconds: 300)}) → Widget

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

Create a FormSlot for this signal.
inc([num by = 1]) → void

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

Short alias for increment. Increments numeric signal by by (default 1).
increment([num by = 1]) → void

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

Increment numeric signal.
interpolated({required Widget to(BuildContext context, double animatedValue), Duration duration = const Duration(milliseconds: 500), Curve curve = Curves.easeOutCubic}) → Widget

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

Create an AnimatedValueSlot that interpolates the numeric value.
lazy({required Widget to(BuildContext context, T value), Widget placeholder(BuildContext context)?}) → Widget

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

Create a lazy slot that defers building.
memoized({required Widget to(BuildContext context, T value), bool equals(T a, T b)?}) → Widget

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

Create a memoized slot with custom equality.

Available on Signal<bool>, provided by the BooleanMorphExtensions extension

Create a menu/close icon morph (hamburger menu).
morph({required MorphableWidget morphBuilder(BuildContext context, T value), MorphConfig config = const MorphConfig(), VoidCallback? onMorphStart, VoidCallback? onMorphComplete}) → Widget

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

Create a MorphSlot for this signal.
morphIcon({required IconData iconBuilder(T value), double size = 24, Color? color, IconMorphStyle style = IconMorphStyle.crossFade, Duration duration = const Duration(milliseconds: 300)}) → Widget

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

Create an IconMorphSlot for this signal.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void
Manually notifies all listeners.
inherited
onActive() → void
Subscribe to source when first listener is added.
override
onInactive() → void
Unsubscribe from source when last listener is removed.
override
persist(SignalPersistence<T> persistence) → PersistentSignal<T>

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

Create a persistent version of this signal.
pipeTo(Signal<T> target) → StreamSubscription<T>

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

Pipe values to another signal.
playPauseMorph({double size = 24, Color? color, IconMorphStyle style = IconMorphStyle.rotateScale}) → Widget

Available on Signal<bool>, provided by the BooleanMorphExtensions extension

Create a play/pause icon morph.
pulsing({required Widget to(BuildContext context, T value), bool when(T value)?, Duration duration = const Duration(milliseconds: 1000)}) → Widget

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

Create a pulsing slot for attention.
removeListener(AtomListener listener) → void
Removes a previously added listener.
inherited
reset() → void
Resets the atom to its initial value.
inherited
select<R>(R selector(S value)) → NeuronAtom<R>
Creates a new atom that selects a part of this atom's value.
inherited
select<S>(S selector(T value)) → SignalSelector<T, S>

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

Create a selector for granular rebuilds.
slot(Widget builder(BuildContext context, T value)) → Widget

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

Create a basic Slot widget from this signal.
smooth({required Widget to(BuildContext context, double animatedValue)}) → Widget

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

Create a smooth spring animation.
snapshot() → T

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

Get current snapshot.
spring({required Widget to(BuildContext context, double animatedValue), SpringConfig config = const SpringConfig(), double? clampMin, double? clampMax}) → Widget

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

Create a SpringSlot with physics-based animation.
sub(num amount) → void

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

Subtract amount from numeric signal and emit. Alias for decrement.
subscribe(VoidCallback listener) → VoidCallback
Adds a listener and returns a callback that cancels the subscription when called.
inherited
tappable({required Widget to(BuildContext context, T value), VoidCallback? onTap, VoidCallback? onDoubleTap, VoidCallback? onLongPress, double pressedScale = 0.95}) → Widget

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

Create a gesture-animated slot.
throttle(Duration duration) → ThrottledSignal<T>

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

Create a throttled version of this signal.
throttled({required Widget to(BuildContext context, T value), Duration duration = const Duration(milliseconds: 100)}) → Widget

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

Create a throttled slot.
toggle() → void

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

Toggle boolean signal.
toString() → String
A string representation of this object.
inherited
transition({required Widget to(BuildContext context, T value), SlotTransition type = SlotTransition.fade, Duration duration = const Duration(milliseconds: 300), Curve curve = Curves.easeInOut}) → Widget

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

Create a TransitionSlot with specified transition type.
undoable({int maxHistory = 50}) → UndoableSignal<T>

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

Create an undoable version of this signal.
visibilityMorph({double size = 24, Color? color, IconMorphStyle style = IconMorphStyle.crossFade}) → Widget

Available on Signal<bool>, provided by the BooleanMorphExtensions extension

Create a visibility toggle icon morph.
when({required bool condition(T value), required Widget to(BuildContext context, T value), Widget orElse(BuildContext context)?}) → Widget

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

Create a conditional slot with when/orElse.

Operators

operator ==(Object other) → bool
The equality operator.
inherited