Function bevy_ecs::schedule::common_conditions::resource_removed
source · pub fn resource_removed<T>() -> impl FnMut(Option<Res<'_, T>>) -> bool + Clonewhere
T: Resource,
Expand description
Generates a Condition
-satisfying closure that returns true
if the resource of the given type has been removed since the condition was last checked.
§Example
app.add_systems(
// `resource_removed` will only return true if the
// given resource was just removed
my_system.run_if(resource_removed::<MyResource>()),
);
#[derive(Resource, Default)]
struct MyResource;
fn my_system(mut counter: ResMut<Counter>) {
counter.0 += 1;
}
world.init_resource::<MyResource>();
// `MyResource` hasn't just been removed so `my_system` won't run
app.run(&mut world);
assert_eq!(world.resource::<Counter>().0, 0);
world.remove_resource::<MyResource>();
// `MyResource` was just removed so `my_system` will run
app.run(&mut world);
assert_eq!(world.resource::<Counter>().0, 1);