watchOnly<T extends Listenable, R> method
like watch but for simple Listenable
objects.
It only triggers a rebuild when the value that
only
returns changes. With that you can react to changes of single members
of T
If only
is null it will trigger a rebuild every time the Listenable
changes
in this case R has to be equal to T
If target
is not null whatch will observe this Object as Listenable instead of
looking inside GetIt
Implementation
R watchOnly<T extends Listenable, R>(
R Function(T)? only, {
T? target,
String? instanceName,
}) =>
widget._state.value.watchOnly<T, R>(
only: only, target: target, instanceName: instanceName);