Cacheable Signal

[Sserra90]

I am not too familiar with Signals but would a cacheable Signal make sense? We can provide an adapter to persist the data using different DB's.

Something like

// Register adapters
main() {
    Signals.registerAdapter(HiveAdapter())
    Signals.registerAdapter(SharedPrefsAdapter())
}

// Create a signal that can be cached
final signal = Signal.cacheable(() => repo.getUser(1), duration: Duration(hours: 12), toJson: (data) => data.toJson, fromJson: (json) => User.fromJson(json));

So the second time you read the signal it retrieve a cached value. This should allow for offline support.

[rodydavis]

Actually right now when you read any signal, future signal, stream signal or computed you get the cached value on subsequent reads.

the second part is interesting thought which is a signal with a lifetime.

there is also a discussion and issue about async computed that might be related.

[Sserra90]

Nice to know it actually caches it, i assume it expires when dispose() is called or when there are no listeners?

Maybe PersistableSignal is a better name then, it persists in time over app restarts etc.

[rodydavis]

Yeah I think that is a better name. And could have methods for read/write to disk or storage.

and yes it will expire if dispose is called, but signals do not automatically reset if no listeners because you can use them outside of effects and they would have no subscribers