useSignalValue<T, S extends ReadonlySignal<T>> function

T useSignalValue<T, S extends ReadonlySignal<T>>(S value, { List<Object?> keys = const <Object>[], })

Subscribes to an existing ReadonlySignal (or Signal) and returns its current value.

This is a convenience hook that is equivalent to invoking useExistingSignal(signal).value. It triggers a rebuild of the host HookWidget whenever the signal's value changes.

Parameters

• value: The existing ReadonlySignal or Signal instance to retrieve the value from and subscribe to.
• keys: A list of objects to watch for changes. If any key changes, the hook will be re-evaluated and subscribe to the new signal.

Returns

The current value T of the signal.

Example

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

final cartItemCountSignal = signal(0);

class CartBadge extends HookWidget {
  const CartBadge({super.key});

  @override
  Widget build(BuildContext context) {
    // Directly extract and subscribe to the signal's value
    final itemCount = useSignalValue(cartItemCountSignal);

    return Badge(
      label: Text('$itemCount'),
      child: const Icon(Icons.shopping_cart),
    );
  }
}

Implementation

T useSignalValue<T, S extends ReadonlySignal<T>>(
  S value, {
  /// A list of objects to watch for changes.
  ///
  /// If any of the keys change, the hook will be re-evaluated.
  List<Object?> keys = const <Object>[],
}) {
  return useExistingSignal(value, keys: keys)();
}