Support destroyObject(o) on ES6 class instances

packages/engine/Source/Core/destroyObject.js

@@ -4,6 +4,27 @@ function returnTrue() {
   return true;
 }
 
+/**
+ * Returns the prototype chain of a given object. Object may be an instance
+ * of an ES6 class, or of a class defined by prototype-based inheritance.
+ *
+ * @param {object} object
+ * @returns {Array<object>}
+ */
+function getPrototypeChain(object) {
+  const prototypes = [];
+
+  let value = object;
+  while ((value = Object.getPrototypeOf(value))) {
+    if (value === Object.prototype) {
+      break;
+    }
+    prototypes.push(value);
+  }
+
+  return prototypes;
+}
+
 /**
  * Destroys an object.  Each of the object's functions, including functions in its prototype,
  * is replaced with a function that throws a {@link DeveloperError}, except for the object's
@@ -40,9 +61,12 @@ function destroyObject(object, message) {
     //>>includeEnd('debug');
   }
 
-  for (const key in object) {
-    if (typeof object[key] === "function") {
-      object[key] = throwOnDestroyed;
+  for (const prototype of getPrototypeChain(object)) {
+    const descriptors = Object.getOwnPropertyDescriptors(prototype);
+    for (const key in descriptors) {
+      if (descriptors[key].writable && typeof object[key] === "function") {
+        object[key] = throwOnDestroyed;
+      }
     }
   }
 

packages/engine/Specs/Core/destroyObjectSpec.js

@@ -0,0 +1,77 @@
+import { destroyObject } from "../../index.js";
+
+describe("Core/destroyObject", function () {
+  it("destroys prototype-based class", function () {
+    function Parent() {}
+    Parent.prototype.isDestroyed = () => false;
+    Parent.prototype.inheritedFn = () => true;
+
+    function Child() {}
+    Child.prototype = new Parent();
+    Child.prototype.instanceFn = () => true;
+    Child.staticFn = () => true;
+
+    Object.defineProperty(Child.prototype, "getterFn", {
+      get: () => {
+        // destroyObject must not execute getters on the target object;
+        // doing so may throw errors if the getter accesses properties
+        // that have already been removed.
+        throw new Error("Getter must not be called.");
+      },
+    });
+
+    const object = new Child();
+
+    expect(object.isDestroyed()).toBe(false);
+    expect(() => object.inheritedFn()).not.toThrowDeveloperError();
+    expect(() => object.instanceFn()).not.toThrowDeveloperError();
+    expect(() => Child.staticFn()).not.toThrowDeveloperError();
+
+    destroyObject(object);
+
+    expect(object.isDestroyed()).toBe(true);
+    expect(() => object.inheritedFn()).toThrowDeveloperError();
+    expect(() => object.instanceFn()).toThrowDeveloperError();
+    expect(() => Child.staticFn()).not.toThrowDeveloperError();
+  });
+
+  it("destroys ES6 class", function () {
+    class Parent {
+      isDestroyed() {
+        return false;
+      }
+      inheritedFn() {
+        return true;
+      }
+    }
+
+    class Child extends Parent {
+      instanceFn() {
+        return true;
+      }
+      staticFn() {
+        return true;
+      }
+      get getterFn() {
+        // destroyObject must not execute getters on the target object;
+        // doing so may throw errors if the getter accesses properties
+        // that have already been removed.
+        throw new Error("Getter must not be called.");
+      }
+    }
+
+    const object = new Child();
+
+    expect(object.isDestroyed()).toBe(false);
+    expect(() => object.inheritedFn()).not.toThrowDeveloperError();
+    expect(() => object.instanceFn()).not.toThrowDeveloperError();
+    expect(() => Child.staticFn()).not.toThrowDeveloperError();
+
+    destroyObject(object);
+
+    expect(object.isDestroyed()).toBe(true);
+    expect(() => object.inheritedFn()).toThrowDeveloperError();
+    expect(() => object.instanceFn()).toThrowDeveloperError();
+    expect(() => Child.staticFn()).not.toThrowDeveloperError();
+  });
+});