Merge pull request #8591 from jony89/patch-1

fix: memory leak event error is not unsubscribing

Author: mramato

CHANGES.md

@@ -19,6 +19,7 @@
 - Fixed an issue with clamping of non-looped glTF animations. Subscribers to animation `update` events should expect one additional event firing as an animation stops. [#7387](https://github.com/CesiumGS/cesium/issues/7387)
 - Fixed a bug with very long view ranges requiring multiple frustums even with the logarithmic depth buffer enabled. Previously, such scenes could resolve depth incorrectly. [#8727](https://github.com/CesiumGS/cesium/pull/8727)
 - Fixed a bug where the elevation contour material's alpha was not being applied. [#8749](https://github.com/CesiumGS/cesium/pull/8749)
+- Fix potential memory leak when destroying `CesiumWidget` instances.
 
 ### 1.68.0 - 2020-04-01
 

Source/Widgets/CesiumWidget/CesiumWidget.js

@@ -366,15 +366,16 @@ function CesiumWidget(container, options) {
     this.targetFrameRate = options.targetFrameRate;
 
     var that = this;
-    scene.renderError.addEventListener(function (scene, error) {
+    this._onRenderError = function (scene, error) {
       that._useDefaultRenderLoop = false;
       that._renderLoopRunning = false;
       if (that._showRenderLoopErrors) {
         var title =
           "An error occurred while rendering.  Rendering has stopped.";
         that.showErrorPanel(title, undefined, error);
       }
-    });
+    };
+    scene.renderError.addEventListener(this._onRenderError);
   } catch (error) {
     if (showRenderLoopErrors) {
       var title = "Error constructing CesiumWidget.";
@@ -709,7 +710,10 @@ CesiumWidget.prototype.isDestroyed = function () {
  * removing the widget from layout.
  */
 CesiumWidget.prototype.destroy = function () {
-  this._scene = this._scene && this._scene.destroy();
+  if (defined(this._scene)) {
+    this._scene.renderError.removeEventListener(this._onRenderError);
+    this._scene = this._scene.destroy();
+  }
   this._container.removeChild(this._element);
   this._creditContainer.removeChild(this._innerCreditContainer);
   destroyObject(this);