From 51c36fd468cdca13d6dd81d7a08941ab9bb3ea5e Mon Sep 17 00:00:00 2001
From: Sam Reid <reids@colorado.edu>
Date: Wed, 6 Apr 2022 15:55:26 -0600
Subject: [PATCH] Fix memory leak, see
 https://github.com/phetsims/center-and-variability/issues/76

---
 js/common/view/CAVScreenView.ts | 66 ++++++++++++++-------------------
 1 file changed, 27 insertions(+), 39 deletions(-)

diff --git a/js/common/view/CAVScreenView.ts b/js/common/view/CAVScreenView.ts
index 323b52ca..6ed650e9 100644
--- a/js/common/view/CAVScreenView.ts
+++ b/js/common/view/CAVScreenView.ts
@@ -162,6 +162,7 @@ class CAVScreenView extends ScreenView {
     model.objectGroup.elementDisposedEmitter.addListener( casObject => {
       const viewNode = map.get( casObject )!;
       objectNodeGroup.disposeElement( viewNode );
+      map.delete( casObject );
     } );
 
     this.topCheckboxGroup = new TopRepresentationCheckboxGroup( model, merge( {
@@ -182,26 +183,26 @@ class CAVScreenView extends ScreenView {
     } );
     this.addChild( this.playAreaMedianIndicatorNode );
 
-    const updateMedianNode = () => {
-      const medianValue = model.medianValueProperty.value;
-      const visible = medianValue !== null && model.isShowingPlayAreaMedianProperty.value;
-
-      if ( visible ) {
-
-        // if there is a ball at that location, go above the ball
-        const ballsAtLocation = model.objectGroup.filter( casObject => casObject.valueProperty.value === medianValue );
-        const modelHeight = ballsAtLocation.length * model.objectType.radius * 2; // assumes no spacing
-
-        const viewHeight = this.modelViewTransform.modelToViewDeltaY( modelHeight );
-
-        this.playAreaMedianIndicatorNode.centerX = this.modelViewTransform.modelToViewX( medianValue );
-        this.playAreaMedianIndicatorNode.bottom = this.modelViewTransform.modelToViewY( 0 ) + viewHeight;
-      }
-      this.playAreaMedianIndicatorNode.visible = visible;
-    };
-    model.medianValueProperty.link( updateMedianNode );
-    model.objectChangedEmitter.addListener( updateMedianNode );
-    model.isShowingPlayAreaMedianProperty.link( updateMedianNode );
+    // const updateMedianNode = () => {
+    //   const medianValue = model.medianValueProperty.value;
+    //   const visible = medianValue !== null && model.isShowingPlayAreaMedianProperty.value;
+    //
+    //   if ( visible ) {
+    //
+    //     // if there is a ball at that location, go above the ball
+    //     const ballsAtLocation = model.objectGroup.filter( casObject => casObject.valueProperty.value === medianValue );
+    //     const modelHeight = ballsAtLocation.length * model.objectType.radius * 2; // assumes no spacing
+    //
+    //     const viewHeight = this.modelViewTransform.modelToViewDeltaY( modelHeight );
+    //
+    //     this.playAreaMedianIndicatorNode.centerX = this.modelViewTransform.modelToViewX( medianValue );
+    //     this.playAreaMedianIndicatorNode.bottom = this.modelViewTransform.modelToViewY( 0 ) + viewHeight;
+    //   }
+    //   this.playAreaMedianIndicatorNode.visible = visible;
+    // };
+    // model.medianValueProperty.link( updateMedianNode );
+    // model.objectChangedEmitter.addListener( updateMedianNode );
+    // model.isShowingPlayAreaMedianProperty.link( updateMedianNode );
 
     this.medianPredictionNode = new PredictionNode( model.medianPredictionProperty, this.modelViewTransform, model.physicalRange, {
       center: this.layoutBounds.center,
@@ -219,15 +220,7 @@ class CAVScreenView extends ScreenView {
     } );
 
     this.resetAllButton = new ResetAllButton( {
-      listener: () => {
-        this.interruptSubtreeInput(); // cancel interactions that may be in progress
-
-        model.reset();
-
-        // hide the dragIndicatorArrowNode and reset the flag for if it has been dragged already
-        objectHasBeenDragged = false;
-        dragIndicatorArrowNode.visible = false;
-      },
+      listener: this.doReset.bind( this ),
       right: this.layoutBounds.maxX - CAVConstants.SCREEN_VIEW_X_MARGIN,
       bottom: this.layoutBounds.maxY - CAVConstants.SCREEN_VIEW_Y_MARGIN,
       tandem: options.tandem.createTandem( 'resetAllButton' )
@@ -235,16 +228,7 @@ class CAVScreenView extends ScreenView {
 
     this.eraseButton = new EraserButton( {
       tandem: options.tandem.createTandem( 'eraseButton' ),
-      listener: () => {
-
-        // Interrupt dragging of existing objects
-        this.interruptSubtreeInput();
-
-        model.clearData();
-
-        // hide the dragIndicatorArrowNode but don't reset objectHasBeenDragged
-        dragIndicatorArrowNode.visible = false;
-      },
+      listener: this.doReset.bind( this ),
       iconWidth: 26,
       right: this.resetAllButton.left - CAVConstants.SCREEN_VIEW_X_MARGIN,
       centerY: this.resetAllButton.centerY
@@ -259,6 +243,10 @@ class CAVScreenView extends ScreenView {
    */
   step( dt: number ): void {
   }
+
+  doReset(): void {
+    this.model.reset();
+  }
 }
 
 centerAndVariability.register( 'CAVScreenView', CAVScreenView );