Removing Value Signal Signatures

[icnahom]

Awesome package @rodydavis, I wanted to ask if you have explored ways to just use signal(value) for Value Signals, instead of listSignal(value) and the like.

Maybe using extension methods as shown in this code:

void main() {
  final todos = signal([]);
  print(todos.isEmpty);
  
  final messages = signal({});
  print(messages.keys);
  
}

Signal<T> signal<T>(T value) => Signal(value);

class Signal<T> {
  const Signal(this.value);
  final T value;
}

extension ListSignalExtension<E> on Signal<List<E>> {
  bool get isEmpty => value.isEmpty;
}

extension MapSignalExtension<K, V> on Signal<Map<K, V>> {
  Iterable<K> get keys => value.keys;
}

[rodydavis]

The first of implementation I started on this path because extensions are awesome and it was a pretty straightforward way to add getters.

Ultimately, I needed to extend with value signal on these core types because of the mutations on some of the setters. I wanted to keep one object in memory, and allow for easy mutation.

This might be no longer relevant with .forceUpdate on value signal.

But Signal does not have that method for API concerns.

Maybe I am being overly cautious and should move forceUpdate to the signal class.

[rodydavis]

Plus extensions cannot overload operators yet, but I believe there is a proposal for it.

[icnahom]

Replicating class members is also not fun, because Dart unlike Swift does not support inheritance for Extensions.

[icnahom]

Should I leave the issue open for exploration?

[Solido]

Yes we may need to dig the idea deeper.

For my uses cases I appreciate that ValueSignal can be a facade as a Data object yet I'm would like to consider how this could be applied to Iterable.

I suspect this can help wrap most of external data structures by not relying on List/Set/Map signals.

@rodydavis

[rodydavis]

I think they can also coexist with extensions on the iterable type and value signals.

One other piece is that with the value signals it will subscribe in effects and computed when calling things like .length, .isEmpty and might be desired.

Extensions would only peek at the value (unless we forced a read)

[Solido]

Another advantage of ValueSignal is the capacity to add methods and states external to the exposed signal itself. I currently rely strongly on them.

[rodydavis]

Going to move this to a discussion!