fix: [#1850] Fix Scene.onActivate/onDeactivate args

CHANGELOG.md

@@ -8,7 +8,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Breaking Changes
 
 - `Timer`'s no longer automatically start when added to a `Scene`, this `Timer.start()` must be called. ([#1865](ttps://github.com/excaliburjs/Excalibur/issues/1865))
-- `Timer.complete` is now read-only to prevent odd bugs, use `reset()`, `stop()`, and `start()` to manipulate timers. 
+- `Timer.complete` is now read-only to prevent odd bugs, use `reset()`, `stop()`, and `start()` to manipulate timers.
 - `Actor.actions.repeat()` and `Actor.actions.repeatForever()` now require a handler that specifies the actions to repeat. This is more clear and helps prevent bugs like #1891
 
   ```typescript
@@ -94,6 +94,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 
+- Fixed issue where `Scene.onActivate/onDeactivate` were called with the wrong arguments ([#1850](https://github.com/excaliburjs/Excalibur/issues/1850))
 - Fixed issue where no width/height argmunents to engine throws an error
 - Fixed issue where zero dimension image draws on the ExcaliburGraphicsContext throw an error
 - Fixed issue where the first scene onInitialize fires at Engine contructor time and before the "play button" clicked ([#1900](https://github.com/excaliburjs/Excalibur/issues/1900))

src/engine/Engine.ts

@@ -853,7 +853,7 @@ O|===|* >________________>\n\
 
       // only deactivate when initialized
       if (this.currentScene.isInitialized) {
-        this.currentScene._deactivate.call(this.currentScene, [oldScene, newScene]);
+        this.currentScene._deactivate.apply(this.currentScene, [oldScene, newScene]);
         this.currentScene.eventDispatcher.emit('deactivate', new DeactivateEvent(newScene, this.currentScene));
       }
 
@@ -864,7 +864,7 @@ O|===|* >________________>\n\
       // initialize the current scene if has not been already
       this.currentScene._initialize(this);
 
-      this.currentScene._activate.call(this.currentScene, [oldScene, newScene]);
+      this.currentScene._activate.apply(this.currentScene, [oldScene, newScene]);
       this.currentScene.eventDispatcher.emit('activate', new ActivateEvent(oldScene, this.currentScene));
     } else {
       this._logger.error('Scene', key, 'does not exist!');

src/spec/SceneSpec.ts

@@ -258,6 +258,31 @@ describe('A scene', () => {
     expect(scene.onInitialize).toHaveBeenCalledTimes(1);
   });
 
+  it('calls onActivate and onDeactivate with the correct args', () => {
+    const mock = new Mocks.Mocker();
+    const sceneA = new ex.Scene();
+    sceneA.onDeactivate = jasmine.createSpy('onDeactivate()');
+    const sceneB = new ex.Scene();
+    sceneB.onActivate = jasmine.createSpy('onActivate()');
+
+    engine.removeScene('root');
+    engine.addScene('root', sceneA);
+    engine.addScene('sceneB', sceneB);
+
+    const loop = mock.loop(engine);
+    engine.goToScene('root');
+    engine.start();
+    loop.advance(100);
+    loop.advance(100);
+
+    engine.goToScene('sceneB');
+    loop.advance(100);
+    loop.advance(100);
+
+    expect(sceneA.onDeactivate).toHaveBeenCalledWith(sceneA, sceneB);
+    expect(sceneB.onActivate).toHaveBeenCalledWith(sceneA, sceneB);
+  });
+
   it('fires initialize before activate', (done) => {
     const scene = new ex.Scene();
     engine.removeScene('root');