has<T> method
Checks whether a provider or override for type T is registered in this container or its ancestors.
Returns true if type T can be resolved without throwing; otherwise false.
if (container.has<NotificationService>()) {
container.inject<NotificationService>().notify('Ready');
}
Implementation
bool has<T>() =>
_overrides.containsKey(T) ||
_bindings.containsKey(T) ||
(parent?.has<T>() ?? false);