Add common component conditions

crates/bevy_ecs/src/schedule/condition.rs

@@ -142,7 +142,7 @@ pub mod common_conditions {
     use crate::{
         change_detection::DetectChanges,
         event::{Event, EventReader},
-        prelude::{Component, Query, With},
+        prelude::{Added, Changed, Component, Query, With},
         removal_detection::RemovedComponents,
         schedule::{State, States},
         system::{IntoSystem, Res, Resource, System},
@@ -894,6 +894,26 @@ pub mod common_conditions {
         move |query: Query<(), With<T>>| !query.is_empty()
     }
 
+    /// Generates a [`Condition`](super::Condition)-satisfying closure that returns `true`
+    /// if the given component type was added to any entities.
+    ///
+    /// Run conditions are evaluated on the main thread, blocking any other systems from running.
+    /// This run condition is relatively expensive, as it iterates over every entity with this component.
+    /// As a result, you likely only want to use this run condition when the number of entities with the component `T` is small.
+    pub fn any_component_added<T: Component>() -> impl FnMut(Query<(), Added<T>>) -> bool {
+        move |query: Query<(), Added<T>>| !query.is_empty()
+    }
+
+    /// Generates a [`Condition`](super::Condition)-satisfying closure that returns `true`
+    /// if the value of the given component type has been changed on any entities.
+    ///
+    /// Run conditions are evaluated on the main thread, blocking any other systems from running.
+    /// This run condition is relatively expensive, as it iterates over every entity with this component.
+    /// As a result, you likely only want to use this run condition when the number of entities with the component `T` is small.
+    pub fn any_component_changed<T: Component>() -> impl FnMut(Query<(), Changed<T>>) -> bool {
+        move |query: Query<(), Changed<T>>| !query.is_empty()
+    }
+
     /// Generates a [`Condition`](super::Condition)-satisfying closure that returns `true`
     /// if there are any entity with a component of the given type removed.
     pub fn any_component_removed<T: Component>() -> impl FnMut(RemovedComponents<T>) -> bool {