Implement a helper function to destroy an array of resources

.changeset/plenty-pots-tell.md

@@ -0,0 +1,5 @@
+---
+"@open-pioneer/core": minor
+---
+
+Add `destroyResources(resources)` to destroy an array of resources.

src/packages/core/index.ts

@@ -9,6 +9,6 @@ export {
     rethrowAbortError
 } from "./error";
 export { EventEmitter, type EventSource, type EventNames } from "./events";
-export { destroyResource, type Resource } from "./resources";
+export { destroyResource, destroyResources, type Resource } from "./resources";
 export { createLogger, type Logger, type LogLevel, type LogMethod } from "./Logger";
 export { createManualPromise, type ManualPromise } from "./utils";

src/packages/core/resources.test.ts

@@ -0,0 +1,43 @@
+// SPDX-FileCopyrightText: 2023 Open Pioneer project (https://github.com/open-pioneer)
+// SPDX-License-Identifier: Apache-2.0
+import { expect, it } from "vitest";
+import { destroyResources, Resource } from "./resources";
+
+it("destroys all resources in the array", () => {
+    const events: string[] = [];
+    const resources: Resource[] = [
+        {
+            destroy() {
+                events.push("destroyed 1");
+            }
+        },
+        {
+            destroy() {
+                events.push("destroyed 2");
+            }
+        }
+    ];
+
+    destroyResources(resources);
+    expect(events).toEqual(["destroyed 2", "destroyed 1"]); // reverse order
+});
+
+it("handles cycles correctly", () => {
+    const events: string[] = [];
+    const resources: Resource[] = [
+        {
+            destroy() {
+                events.push("destroyed 1");
+                destroyResources(resources); // still only destroys each resource only once
+            }
+        },
+        {
+            destroy() {
+                events.push("destroyed 2");
+            }
+        }
+    ];
+
+    destroyResources(resources);
+    expect(events).toEqual(["destroyed 2", "destroyed 1"]);
+});

src/packages/core/resources.ts

@@ -27,3 +27,19 @@ export function destroyResource<R extends Resource>(resource: R | undefined): un
     resource?.destroy();
     return undefined;
 }
+
+/**
+ * A helper function that invokes `destroy()` on each resource in the given array.
+ *
+ * This function destroys the resources in reverse order (starting from the last element).
+ * This is done to reverse the order of construction.
+ *
+ * The array will be cleared by this function.
+ */
+export function destroyResources<R extends Resource>(resources: R[]): void {
+    // `destroy()` might call us in a cycle, so we modify the array in place.
+    let resource: Resource | undefined;
+    while ((resource = resources.pop())) {
+        resource.destroy();
+    }
+}