test(vue-model-api): test eviction from Cache after garbage collection

Author: Oleksandr Dzhychko

vue-model-api/package.json

@@ -14,7 +14,7 @@
   ],
   "scripts": {
     "build": "tsc --build",
-    "test": "jest",
+    "test": "node --expose-gc node_modules/.bin/jest",
     "prettier": "prettier . --check",
     "prettier:fix": "npm run prettier -- --write"
   },

vue-model-api/src/internal/Cache.test.ts

@@ -1,5 +1,6 @@
 import type { INodeJS } from "@modelix/ts-model-api";
 import { Cache } from "./Cache";
+import { runGarbageCollection } from "./runGarbageCollection";
 
 test("wrapper is added to cache", () => {
   const cache = new Cache<{ id: string }>();
@@ -17,3 +18,16 @@ test("wrapper is added to cache", () => {
   const wrapped2 = cache.memoize(node, wrap2);
   expect(wrapped2.id).toBe("aWrapper1");
 });
+
+test("wrapper is removed from cache after garbage collection", async () => {
+  const iNode = {
+    getReference() {
+      return "myKey";
+    },
+  } as INodeJS;
+  const cache = new Cache();
+  cache.memoize(iNode, () => ({}));
+  expect(cache.get(iNode)).not.toBeUndefined();
+  await runGarbageCollection();
+  expect(cache.get(iNode)).toBeUndefined();
+});

vue-model-api/src/internal/runGarbageCollection.test.ts

@@ -0,0 +1,7 @@
+import { runGarbageCollection } from "./runGarbageCollection";
+
+test("test garbage collection invocation", async () => {
+  const weakRef = new WeakRef({});
+  await runGarbageCollection();
+  expect(weakRef.deref()).toBeUndefined();
+});

vue-model-api/src/internal/runGarbageCollection.ts

@@ -0,0 +1,16 @@
+/**
+ * Force garbage collection to run.
+ * See https://github.com/orgs/nodejs/discussions/36467
+ **/
+export async function runGarbageCollection() {
+  // Enqueue a micro task is needed to run before garbage collection
+  // See https://github.com/orgs/nodejs/discussions/36467#discussioncomment-3367722
+  await new Promise((resolve) => setTimeout(resolve, 0));
+  if (global.gc) {
+    global.gc();
+  } else {
+    fail(
+      "Garbage collection unavailable. Pass --expose-gc when launching node to enable forced garbage collection.",
+    );
+  }
+}

vue-model-api/tsconfig.json

@@ -1,7 +1,7 @@
 {
   "extends": "@tsconfig/recommended/tsconfig.json",
   "include": ["src/**/*.ts"],
-  "exclude": ["src/**/*.test.ts"],
+  "exclude": ["src/**/*.test.ts", "src/**/runGarbageCollection.ts"],
   "compilerOptions": {
     "composite": true,
     "rootDir": "src",