Computed<T> class

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.

Computed class extends the Signal class, so you can use it anywhere you would use a signal.

import 'package:signals/signals.dart';

final name = signal("Jane");
final surname = signal("Doe");

final fullName = computed(() => name.value + " " + surname.value);

// Logs: "Jane Doe"
print(fullName.value);

// Updates flow through computed, but only if someone
// subscribes to it. More on that later.
name.value = "John";
// Logs: "John Doe"
print(fullName.value);

Any signal that is accessed inside the computed's callback function will be automatically subscribed to and tracked as a dependency of the computed signal.

Computed signals are both lazily evaluated and memoized

Force Re-evaluation

You can force a computed signal to re-evaluate by calling its .recompute method. This will re-run the computed callback and update the computed signal's value.

final name = signal("Jane");
final surname = signal("Doe");
final fullName = computed(() => name.value + " " + surname.value);

fullName.recompute(); // Re-runs the computed callback

Disposing

Auto Dispose

If a computed signal is created with autoDispose set to true, it will automatically dispose itself when there are no more listeners.

final s = computed(() => 0, autoDispose: true);
s.onDispose(() => print('Signal destroyed'));
final dispose = s.subscribe((_) {});
dispose();
final value = s.value; // 0
// prints: Signal destroyed

A auto disposing signal does not require its dependencies to be auto disposing. When it is disposed it will freeze its value and stop tracking its dependencies.

This means that it will no longer react to changes in its dependencies.

final s = computed(() => 0);
s.dispose();
final value = s.value; // 0
final b = computed(() => s.value); // 0
// b will not react to changes in s

You can check if a signal is disposed by calling the .disposed method.

final s = computed(() => 0);
print(s.disposed); // false
s.dispose();
print(s.disposed); // true

On Dispose Callback

You can attach a callback to a signal that will be called when the signal is destroyed.

final s = computed(() => 0);
s.onDispose(() => print('Signal destroyed'));
s.dispose();

Flutter

In Flutter if you want to create a signal that automatically disposes itself when the widget is removed from the widget tree and rebuilds the widget when the signal changes, you can use the createComputed inside a stateful widget.

import 'package:flutter/material.dart';
import 'package:signals/signals_flutter.dart';

class CounterWidget extends StatefulWidget {
  @override
  _CounterWidgetState createState() => _CounterWidgetState();
}

class _CounterWidgetState extends State<CounterWidget> with SignalsMixin {
  late final counter = createSignal(0);
  late final isEven = createComputed(() => counter.value.isEven);
  late final isOdd = createComputed(() => counter.value.isOdd);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text('Counter: even=$isEven, odd=$isOdd'),
            ElevatedButton(
              onPressed: () => counter.value++,
              child: Text('Increment'),
            ),
          ],
        ),
      ),
    );
  }
}

No Watch widget or extension is needed, the signal will automatically dispose itself when the widget is removed from the widget tree.

The SignalsMixin is a mixin that automatically disposes all signals created in the state when the widget is removed from the widget tree.

Testing

Testing computed signals is possible by converting a computed to a stream and testing it like any other stream in Dart.

test('test as stream', () {
    final a = signal(0);
    final s = computed(() => a());
    final stream = s.toStream();

    a.value = 1;
    a.value = 2;
    a.value = 3;

    expect(stream, emitsInOrder([0, 1, 2, 3]));
});

emitsInOrder is a matcher that will check if the stream emits the values in the correct order which in this case is each value after a signal is updated.

You can also override the initial value of a computed signal when testing. This is is useful for mocking and testing specific value implementations.

test('test with override', () {
    final a = signal(0);
    final s = computed(() => a()).overrideWith(-1);

    final stream = s.toStream();

    a.value = 1;
    a.value = 2;
    a.value = 2; // check if skipped
    a.value = 3;

    expect(stream, emitsInOrder([-1, 1, 2, 3]));
});

overrideWith returns a new computed signal with the same global id sets the value as if the computed callback returned it. @link https://dartsignals.dev/core/computed

Implemented types

ReadonlySignal<T>

Mixed-in types

ReadonlySignalMixin<T>
SignalsAutoDisposeMixin<T>

Available extensions

Constructors

Computed(T fn(), {String? debugLabel, bool autoDispose = false}): 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.

Properties

autoDispose ↔ bool: Throws and error if read after dispose and can be disposed on last unsubscribe.
getter/setter pairinherited
bitLength → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns the minimum number of bits required to store this integer.
no setter
codeUnits → List<int>: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
An unmodifiable list of the UTF-16 code units of this string.
no setter
debugLabel → String?: Debug label for Debug Mode
final
disposed ↔ bool: Check if the effect is disposed
getter/setter pairinherited
entries → Iterable<MapEntry<K, V>>: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension

no setter
first → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

no setter
flags ↔ int: getter/setter pairinherited
globalId → int: finalinherited
hashCode → int: The hash code for this object.
no setterinherited
index → int: Available on ReadonlySignal<Enum>, provided by the EnumSignalExtension extension
A numeric identifier for the enumerated value.
no setter
internalValue ↔ T: getter/setter pairinherited-getter
isEmpty → bool: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Whether this string is empty.
no setter
isEmpty → bool: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

no setter
isEmpty → bool: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension

no setter
isEven → bool: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns true if and only if this integer is even.
no setter
isFinite → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is finite.
no setter
isInfinite → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is positive infinity or negative infinity.
no setter
isInitialized → bool: Check if a signal value is set (does not subscribe)
no setterinherited
isNaN → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is a Not-a-Number value.
no setter
isNegative → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is negative.
no setter
isNotEmpty → bool: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Whether this string is not empty.
no setter
isNotEmpty → bool: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension

no setter
isNotEmpty → bool: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

no setter
isOdd → bool: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns true if and only if this integer is odd.
no setter
iterator → Iterator<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

no setter
keys → Iterable<K>: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension

no setter
last → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

no setter
last → E: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension

no setter
length → int: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
The length of the string.
no setter
length → int: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

no setter
length → int: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension

no setter
name → String: Available on ReadonlySignal<Enum>, provided by the EnumSignalExtension extension
The name of the enum value.
no setter
reversed → Iterable<E>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension

no setter
runes → Runes: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
An Iterable of Unicode code-points of this string.
no setter
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
sign → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Negative one, zero or positive one depending on the sign and numerical value of this number.
no setter
sign → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns the sign of this integer.
no setter
sign → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
The sign of the double's numerical value.
no setter
single → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

no setter
sources ↔ Node?: getter/setter pairinherited
value → T: Compute the current value
no setter
values → Iterable<V>: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension

no setter
version ↔ int: getter/setter pairinherited

Methods

abs() → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
abs() → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns the absolute value of this integer.
abs() → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The absolute value of this number.
afterCreate(T val) → void: Internal hook for after a signal is created
allMatches(String string, [int start = 0]) → Iterable<Match>: Available on ReadonlySignal<Pattern>, provided by the PatternSignalExtension extension
Matches this pattern against the string repeatedly.
any(bool test(E element)) → bool: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
asMap() → Map<int, E>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
beforeUpdate(T val) → void: Internal hook for after a signal is updated
call() → T: Return the value when invoked
inherited
cast<R>() → Set<R>: Available on ReadonlySignal<Set<E>>, provided by the ReadonlySetSignalExtension extension
cast<R>() → Iterable<R>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
cast<RK, RV>() → Map<RK, RV>: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension
cast<R>() → List<R>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
ceil() → int: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the least integer that is not smaller than this number.
ceil() → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.
ceil() → int: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The least integer no smaller than this.
ceilToDouble() → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the least integer double value no smaller than this.
ceilToDouble() → double: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.toDouble().
ceilToDouble() → double: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Returns the least double integer value no smaller than this.
clamp(num lowerLimit, num upperLimit) → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Returns this num clamped to be in the range lowerLimit-upperLimit.
codeUnitAt(int index) → int: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Returns the 16-bit UTF-16 code unit at the given index.
compareTo(T other) → int: Available on ReadonlySignal<T>, provided by the ComparableSignalExtension extension
Compares this object to another object.
contains(Pattern other, [int startIndex = 0]) → bool: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Whether this string contains a match of other.
contains(Object? value) → bool: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
containsAll(Iterable<Object?> other) → bool: Available on ReadonlySignal<Set<E>>, provided by the ReadonlySetSignalExtension extension
containsKey(Object? key) → bool: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension
containsValue(Object? value) → bool: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension
difference(Set<Object?> other) → Set<E>: Available on ReadonlySignal<Set<E>>, provided by the ReadonlySetSignalExtension extension
dispose() → void: Dispose the signal
override
elementAt(int index) → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
endsWith(String other) → bool: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Whether this string ends with other.
every(bool test(E element)) → bool: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
expand<R>(Iterable<R> toElements(E element)) → Iterable<R>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
expand<R>(Iterable<R> toElements(E element)) → Iterable<R>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
firstWhere(bool test(E element), {E orElse()?}) → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
firstWhere(bool test(E element), {E orElse()?}) → E: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
floor() → int: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the greatest integer no greater than this number.
floor() → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.
floor() → int: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The greatest integer no greater than this number.
floorToDouble() → double: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.toDouble().
floorToDouble() → double: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Returns the greatest double integer value no greater than this.
floorToDouble() → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the greatest integer double value no greater than this.
fold<R>(R initialValue, R combine(R previousValue, E element)) → R: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
fold<R>(R initialValue, R combine(R previousValue, E element)) → R: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
followedBy(Iterable<E> other) → Iterable<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
followedBy(Iterable<E> other) → Iterable<E>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
forEach(void action(E element)) → void: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
gcd(int other) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns the greatest common divisor of this integer and other.
get() → T: Helper method to get the current value
inherited
getRange(int start, int end) → Iterable<E>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
indexOf(E element, [int start = 0]) → int: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
indexOf(Pattern pattern, [int start = 0]) → int: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Returns the position of the first match of pattern in this string, starting at start, inclusive:
indexWhere(bool test(E element), [int start = 0]) → int: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
internalRefresh() → bool: inherited
intersection(Set<Object?> other) → Set<E>: Available on ReadonlySignal<Set<E>>, provided by the ReadonlySetSignalExtension extension
join([String separator = ""]) → String: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
lastIndexOf(Pattern pattern, [int? start]) → int: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
The starting position of the last match pattern in this string.
lastIndexOf(E element, [int? start]) → int: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
lastIndexWhere(bool test(E element), [int? start]) → int: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
lastWhere(bool test(E element), {E orElse()?}) → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
lookup(Object? object) → E?: Available on ReadonlySignal<Set<E>>, provided by the ReadonlySetSignalExtension extension
map<R>(R toElement(E e)) → Iterable<R>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
map<K2, V2>(MapEntry<K2, V2> convert(K key, V value)) → Map<K2, V2>: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension
matchAsPrefix(String string, [int start = 0]) → Match?: Available on ReadonlySignal<Pattern>, provided by the PatternSignalExtension extension
Matches this pattern against the start of string.
modInverse(int modulus) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns the modular multiplicative inverse of this integer modulo modulus.
modPow(int exponent, int modulus) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this integer to the power of exponent modulo modulus.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
notify() → void: inherited
observe(Widget builder(T), {Key? key, void onInit(T value)?, Function? onValueUpdated, void onAfterBuild(T value)?, void onDispose(T value)?, bool shouldRebuild(T newValue, T oldValue)?, bool shouldNotify(T newValue, T oldValue)?, bool equals(T a, T b)?, Duration? debounce, Duration? throttle, void onError(Object error, StackTrace stack)?, Widget errorBuilder(Object error)?, Widget loadingBuilder()?, String? debugLabel, bool debugPrint = false}) → SignalsWatch<T>: Available on ReadonlySignal<T>, provided by the SignalObserveExtension extension
Observe this signal and rebuild when it changes.
onDispose(void cleanup()) → void Function(): Add a cleanup function to be called when the signal is disposed
inherited
overrideWith(T val) → Computed<T>: Override the current signal with a new value as if it was created with it
padLeft(int width, [String padding = ' ']) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Pads this string on the left if it is shorter than width.
padRight(int width, [String padding = ' ']) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Pads this string on the right if it is shorter than width.
peek() → T: In the rare instance that you have an effect that should write to another signal based on the previous value, but you don't want the effect to be subscribed to that signal, you can read a signals's previous value via signal.peek().
inherited
readonly() → ReadonlySignal<T>: Returns a readonly signal
recompute() → void: Call the computed function and update the value
reduce(E combine(E value, E element)) → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
remainder(num other) → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
remainder(num other) → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The remainder of the truncating division of this by other.
replaceAll(Pattern from, String replace) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Replaces all substrings that match from with replace.
replaceAllMapped(Pattern from, String replace(Match match)) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Replace all substrings that match from by a computed string.
replaceFirst(Pattern from, String to, [int startIndex = 0]) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Creates a new string with the first occurrence of from replaced by to.
replaceFirstMapped(Pattern from, String replace(Match match), [int startIndex = 0]) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Replace the first occurrence of from in this string.
replaceRange(int start, int? end, String replacement) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Replaces the substring from start to end with replacement.
round() → int: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the integer closest to this number.
round() → int: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The integer closest to this number.
round() → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.
roundToDouble() → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the integer double value closest to this.
roundToDouble() → double: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The double integer value closest to this value.
roundToDouble() → double: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.toDouble().
select<R>(R selector(ReadonlySignal<T>), {bool? autoDispose = false, String? debugLabel}) → Computed<R>: Available on ReadonlySignal<T>, provided by the ReadonlySignalUtils extension
Select a value and return a computed signal to listen for changes
selectObserve<S>(S selector(dynamic), Widget builder(S), {Key? key, void onInit(S value)?, Function? onValueUpdated, void onAfterBuild(S value)?, void onDispose(S value)?, bool shouldRebuild(S newValue, S oldValue)?, bool shouldNotify(S newValue, S oldValue)?, bool equals(S a, S b)?, Duration? debounce, Duration? throttle, void onError(Object error, StackTrace stack)?, Widget errorBuilder(Object error)?, Widget loadingBuilder()?, String? debugLabel, bool debugPrint = false}) → SignalsWatch<S>: Available on ReadonlySignal<T>, provided by the SignalObserveExtension extension
Select a specific part of this signal's value and only rebuild when that part changes.
singleWhere(bool test(E element), {E orElse()?}) → E: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
skip(int count) → Iterable<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
skipWhile(bool test(E value)) → Iterable<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
sorted([int compare(E a, E b)?]) → List<E>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
Return a new array that is sorted by the compare function
split(Pattern pattern) → List<String>: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Splits the string at matches of pattern and returns a list of substrings.
splitMapJoin(Pattern pattern, {String onMatch(Match)?, String onNonMatch(String)?}) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Splits the string, converts its parts, and combines them into a new string.
startsWith(Pattern pattern, [int index = 0]) → bool: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Whether this string starts with a match of pattern.
sublist(int start, [int? end]) → List<E>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
subscribe(void fn(T value)) → void Function(): Subscribe to value changes with a dispose function
inherited
subscribeToNode(Node node) → void: inherited
substring(int start, [int? end]) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
The substring of this string from start, inclusive, to end, exclusive.
take(int count) → Iterable<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
takeWhile(bool test(E value)) → Iterable<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
toDouble() → double: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
This number as a double.
toInt() → int: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Truncates this num to an integer and returns the result as an int.
toJson() → dynamic: Convert value to JSON
inherited
toList({bool growable = true}) → List<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
toLowerCase() → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Converts all characters in this string to lower case.
toRadixString(int radix) → String: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Converts this int to a string representation in the given radix.
toSet() → Set<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
toSigned(int width) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns the least significant width bits of this integer, extending the highest retained bit to the sign. This is the same as truncating the value to fit in width bits using an signed 2-s complement representation. The returned value has the same bit value in all positions higher than width.
toStream() → Stream<T>: Available on ReadonlySignal<T>, provided by the ReadonlySignalUtils extension
Convert a signal to a Stream to be consumed as a read only stream.
toString() → String: A string representation of this object.
inherited
toStringAsExponential([int? fractionDigits]) → String: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
An exponential string-representation of this number.
toStringAsFixed(int fractionDigits) → String: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
A decimal-point string-representation of this number.
toStringAsPrecision(int precision) → String: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
A string representation with precision significant digits.
toUnsigned(int width) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns the least significant width bits of this integer as a non-negative number (i.e. unsigned representation). The returned value has zeros in all bit positions higher than width.
toUpperCase() → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Converts all characters in this string to upper case.
transform<R>(R transform(T), {Key? key, required Widget builder(R), void onInit(R value)?, Function? onValueUpdated, void onAfterBuild(R value)?, void onDispose(R value)?, bool shouldRebuild(R newValue, R oldValue)?, bool shouldNotify(R newValue, R oldValue)?, bool equals(R a, R b)?, Duration? debounce, Duration? throttle, void onError(Object error, StackTrace stack)?, Widget errorBuilder(Object error)?, Widget loadingBuilder()?, String? debugLabel, bool debugPrint = false}) → SignalsWatch<R>: Available on ReadonlySignal<T>, provided by the SignalObserveExtension extension
Transform this signal's value and observe the result with error handling.
trim() → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
The string without any leading and trailing whitespace.
trimLeft() → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
The string without any leading whitespace.
trimRight() → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
The string without any trailing whitespace.
truncate() → int: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The integer obtained by discarding any fractional digits from this.
truncate() → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.
truncate() → int: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the integer obtained by discarding any fractional part of this number.
truncateToDouble() → double: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Returns this.toDouble().
truncateToDouble() → double: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Returns the double integer value obtained by discarding any fractional digits from the double value of this.
truncateToDouble() → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
Returns the integer double value obtained by discarding any fractional digits from this.
union(Set<E> other) → Set<E>: Available on ReadonlySignal<Set<E>>, provided by the ReadonlySetSignalExtension extension
unsubscribeFromNode(Node node) → void
unwatch(BuildContext context) → void: Available on ReadonlySignal<T>, provided by the FlutterReadonlySignalUtils extension
Stop subscriptions to updates on a signal for watchers
watch(BuildContext context, {String? debugLabel}) → T: Available on ReadonlySignal<T>, provided by the FlutterReadonlySignalUtils extension
Rebuild the Element that the current signal is inside of
where(bool test(E element)) → Iterable<E>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension
whereType<R>() → Iterable<R>: Available on ReadonlySignal<Iterable<E>>, provided by the ReadonlyIterableSignalExtension extension

Operators

operator %(num other) → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Euclidean modulo of this number by other.
operator %(num other) → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
operator &(bool other) → bool: Available on ReadonlySignal<bool>, provided by the BoolSignalExtension extension
The logical conjunction ("and") of this and other.
operator &(int other) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Bit-wise and operator.
operator *(num other) → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
operator *(int times) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Creates a new string by concatenating this string with itself a number of times.
operator *(num other) → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Multiplies this number by other.
operator +(String other) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
Creates a new string by concatenating this string with other.
operator +(List<E> other) → List<E>: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
operator +(num other) → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
operator +(num other) → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Adds other to this number.
operator -(num other) → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
operator -(num other) → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Subtracts other from this number.
operator /(num other) → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
operator /(num other) → double: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Divides this number by other.
operator <(num other) → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is numerically smaller than other.
operator <<(int shiftAmount) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Shift the bits of this integer to the left by shiftAmount.
operator <=(num other) → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is numerically smaller than or equal to other.
operator ==(Object other) → bool: The equality operator.
inherited
operator >(num other) → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is numerically greater than other.
operator >=(num other) → bool: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Whether this number is numerically greater than or equal to other.
operator >>(int shiftAmount) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Shift the bits of this integer to the right by shiftAmount.
operator >>>(int shiftAmount) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Bitwise unsigned right shift by shiftAmount bits.
operator [](int index) → E: Available on ReadonlySignal<List<E>>, provided by the ReadonlyListSignalExtension extension
operator [](Object? key) → V?: Available on ReadonlySignal<Map<K, V>>, provided by the ReadonlyMapSignalExtension extension
operator [](int index) → String: Available on ReadonlySignal<String>, provided by the StringSignalExtension extension
The character (as a single-code-unit String) at the given index.
operator ^(int other) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Bit-wise exclusive-or operator.
operator ^(bool other) → bool: Available on ReadonlySignal<bool>, provided by the BoolSignalExtension extension
The logical exclusive disjunction ("exclusive or") of this and other.
operator unary-() → num: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
The negation of this value.
operator unary-() → double: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension
operator unary-() → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Return the negative value of this integer.
operator |(int other) → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
Bit-wise or operator.
operator |(bool other) → bool: Available on ReadonlySignal<bool>, provided by the BoolSignalExtension extension
The logical disjunction ("inclusive or") of this and other.
operator ~() → int: Available on ReadonlySignal<int>, provided by the IntSignalExtension extension
The bit-wise negate operator.
operator ~/(num other) → int: Available on ReadonlySignal<num>, provided by the NumSignalExtension extension
Truncating division operator.
operator ~/(num other) → int: Available on ReadonlySignal<double>, provided by the DoubleSignalExtension extension