feat: Add removeWhere to Component (#1878)

Since removeWhere will be removed from the ComponentSet in #1877 we should expose it on the component.

packages/flame/lib/src/components/core/component.dart

@@ -580,6 +580,15 @@ class Component {
     components.forEach(remove);
   }
 
+  /// Removes all the children for which the [test] function returns true.
+  void removeWhere(bool Function(Component component) test) {
+    children.forEach((component) {
+      if (test(component)) {
+        remove(component);
+      }
+    });
+  }
+
   /// Remove the component from its parent in the next tick.
   void removeFromParent() {
     _parent?.remove(this);

packages/flame/test/components/component_test.dart

@@ -33,6 +33,12 @@ class _ParentOnPrepareComponent extends _OnPrepareComponent {
   }
 }
 
+class _IdentifiableComponent extends Component {
+  final int id;
+
+  _IdentifiableComponent(this.id);
+}
+
 void main() {
   final prepareGame = FlameTester(_PrepareGame.new);
 
@@ -344,6 +350,26 @@ void main() {
           game.update(0);
         },
       );
+
+      testWithFlameGame(
+        'removeWhere removes the correct components',
+        (game) async {
+          final components = List.generate(
+            10,
+            _IdentifiableComponent.new,
+          );
+          game.addAll(components);
+          await game.ready();
+          expect(game.children.length, 10);
+          game.removeWhere((c) => (c as _IdentifiableComponent).id.isEven);
+          game.update(0);
+          expect(game.children.length, 5);
+          expect(
+            game.children.every((c) => (c as _IdentifiableComponent).id.isOdd),
+            true,
+          );
+        },
+      );
     });
 
     prepareGame.test(

packages/flame_bloc/example/lib/src/game/game.dart

@@ -2,7 +2,6 @@ import 'package:flame/components.dart';
 import 'package:flame/game.dart';
 import 'package:flame/input.dart';
 import 'package:flame_bloc/flame_bloc.dart';
-
 import 'package:flame_bloc_example/src/game/components/enemy.dart';
 import 'package:flame_bloc_example/src/game/components/enemy_creator.dart';
 import 'package:flame_bloc_example/src/game/components/player.dart';
@@ -19,7 +18,7 @@ class GameStatsController extends Component with HasGameRef<SpaceShooterGame> {
               newState.status == GameStatus.initial;
         },
         onNewState: (state) {
-          gameRef.children.removeWhere((element) => element is EnemyComponent);
+          gameRef.removeWhere((element) => element is EnemyComponent);
         },
       ),
     );