ValueNotifier should have an addValueListener method.

[TimeLex]

Use case

A listener of a ValueNotifier often needs the value itself when it is called, but the addListener method does not return the value of the ValueNotifier. It is often easier to get the value within the listener, for example in this case:

ValueNotifier<bool> loadingNotifier = getLoadingNotifier();
loadingNotifier.addListener(() => print("isLoading: ${loadingNotifier.value}"));

Before adding the listener, a variable must be created that can then be called within the listener.

It would be easier to pass the variable to the listener as follows:

getLoadingNotifier().addValueListener((isLoading) => print("isLoading: $isLoading"));

Proposal

The ValueNotifier should have an addValueListener-Method which passes the value to its listeners.

void addValueListener(void Function(T value) listener);