useSignalValue

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.

This hook is the preferred way to consume external/global signals when you only need read-only access to their values and want standard Flutter Hook ergonomics.

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),
    );
  }
}