fix(): jest should not count PerformanceObserver as an open handle

CHANGELOG.md

@@ -25,6 +25,7 @@
 
 ### Fixes
 
+- `[jest-core]` Don't report PerformanceObserver as open handle ([#11123](https://github.com/facebook/jest/pull/11123))
 - `[babel-plugin-jest-hoist]` Add `__dirname` and `__filename` to whitelisted globals ([#10903](https://github.com/facebook/jest/pull/10903))
 - `[expect]` [**BREAKING**] Revise `expect.not.objectContaining()` to be the inverse of `expect.objectContaining()`, as documented. ([#10708](https://github.com/facebook/jest/pull/10708))
 - `[expect]` [**BREAKING**] Make `toContain` more strict with the received type ([#10119](https://github.com/facebook/jest/pull/10119) & [#10929](https://github.com/facebook/jest/pull/10929))

packages/jest-core/src/__tests__/collectHandles.test.js

@@ -0,0 +1,35 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+
+import {PerformanceObserver} from 'perf_hooks';
+import collectHandles from '../collectHandles';
+
+describe('collectHandles', () => {
+  it('should collect Timeout', () => {
+    const handleCollector = collectHandles();
+
+    const interval = setInterval(() => {}, 100);
+
+    const openHandles = handleCollector();
+
+    expect(openHandles.length).toEqual(1);
+    expect(openHandles[0].message).toContain('Timeout');
+
+    clearInterval(interval);
+  });
+
+  it('should not collect the PerformanceObserver open handle', () => {
+    const handleCollector = collectHandles();
+    const obs = new PerformanceObserver((list, observer) => {});
+    obs.observe({entryTypes: ['mark']});
+
+    const openHandles = handleCollector();
+
+    expect(openHandles.length).toEqual(0);
+  });
+});

packages/jest-core/src/collectHandles.ts

@@ -57,7 +57,8 @@ export default function collectHandles(): () => Array<Error> {
       if (
         type === 'PROMISE' ||
         type === 'TIMERWRAP' ||
-        type === 'ELDHISTOGRAM'
+        type === 'ELDHISTOGRAM' ||
+        type === 'PerformanceObserver'
       ) {
         return;
       }