useLinkedSignal<T, S> function

LinkedSignal<T, S> useLinkedSignal<T, S>(S source(), { List<Object?> keys = const <Object>[], LinkedSignalOptions<T, S>? options, })

Creates a new LinkedSignal that resets its value whenever its source computation changes.

A LinkedSignal is a specialized signal that "links" to another reactive source or computed value, automatically updating or resetting itself based on a custom computation function when the source changes.

Parameters

• source: A computation function that yields the source value of type S.
• options: Configuration options for the linked signal, detailing how the source value S maps to the signal's inner value T.
• keys: A list of objects to watch. If any key changes, the signal is re-created.

Example

import 'package:flutter/material.dart';
import 'package:flutter_hooks/flutter_hooks.dart';
import 'package:signals_hooks/signals_hooks.dart';

class ProfileEditor extends HookWidget {
  final String initialUsername;
  const ProfileEditor({required this.initialUsername, super.key});

  @override
  Widget build(BuildContext context) {
    // LinkedSignal resets to initialUsername if the prop initialUsername changes,
    // but allows local modifications in the meantime.
    final usernameSignal = useLinkedSignal(
      () => initialUsername,
      keys: [initialUsername],
      options: LinkedSignalOptions(
        computation: (source, previous) => source,
      ),
    );

    return Column(
      children: [
        TextField(
          controller: useTextEditingController(text: usernameSignal.value)
            ..addListener(() {
              // Local modifications allowed
              usernameSignal.value = usernameSignal.value;
            }),
        ),
        Text('Live Username Signal: ${usernameSignal.value}'),
      ],
    );
  }
}

Implementation

LinkedSignal<T, S> useLinkedSignal<T, S>(
  S Function() source, {
  List<Object?> keys = const <Object>[],
  LinkedSignalOptions<T, S>? options,
}) {
  final s = useMemoized(
    () => linkedSignal<T, S>(source, options: options),
    keys,
  );
  return useExistingSignal(s, keys: keys);
}