fix(ext/node): add stubs for perf_hooks.PerformaceObserver (#23958)

Fixes https://github.com/denoland/deno/issues/23943

2 files changed, 12 insertions, 4 deletions

diff --git a/ext/node/polyfills/perf_hooks.ts b/ext/node/polyfills/perf_hooks.ts
index 44ab88f98..b58321ffa 100644
--- a/ext/node/polyfills/perf_hooks.ts
+++ b/ext/node/polyfills/perf_hooks.ts
@@ -9,8 +9,15 @@ import {
   PerformanceEntry,
 } from "ext:deno_web/15_performance.js";
 
-// FIXME(bartlomieju)
-const PerformanceObserver = undefined;
+class PerformanceObserver {
+  observe() {
+    notImplemented("PerformanceObserver.observe");
+  }
+  disconnect() {
+    notImplemented("PerformanceObserver.disconnect");
+  }
+}
+
 const constants = {};
 
 const performance:
diff --git a/tests/unit_node/perf_hooks_test.ts b/tests/unit_node/perf_hooks_test.ts
index d6f58d1cf..86c4aee4c 100644
--- a/tests/unit_node/perf_hooks_test.ts
+++ b/tests/unit_node/perf_hooks_test.ts
@@ -1,6 +1,6 @@
 // Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
 import * as perfHooks from "node:perf_hooks";
-import { performance } from "node:perf_hooks";
+import { performance, PerformanceObserver } from "node:perf_hooks";
 import { assertEquals, assertThrows } from "@std/assert/mod.ts";
 
 Deno.test({
@@ -44,9 +44,10 @@ Deno.test({
 });
 
 Deno.test({
-  name: "[perf_hooks] PerformanceEntry",
+  name: "[perf_hooks] PerformanceEntry & PerformanceObserver",
   fn() {
     assertEquals<unknown>(perfHooks.PerformanceEntry, PerformanceEntry);
+    assertEquals<unknown>(perfHooks.PerformanceObserver, PerformanceObserver);
   },
 });