From e00852c526f128e750752df706a5eacca6d03f41 Mon Sep 17 00:00:00 2001
From: David Ortner <david@ortner.se>
Date: Tue, 14 May 2024 18:38:55 +0200
Subject: [PATCH] fix: [#1336] Adds check for if Window and MutationObserver
 has been destroyed when triggering listeners

---
 .../src/mutation-observer/MutationListener.ts | 10 ++++--
 .../MutationObserver.test.ts                  | 35 ++++++++++++++++---
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/packages/happy-dom/src/mutation-observer/MutationListener.ts b/packages/happy-dom/src/mutation-observer/MutationListener.ts
index 789300c5d..6a3fdeb0a 100644
--- a/packages/happy-dom/src/mutation-observer/MutationListener.ts
+++ b/packages/happy-dom/src/mutation-observer/MutationListener.ts
@@ -13,7 +13,7 @@ export default class MutationListener {
 	#window: BrowserWindow;
 	#observer: MutationObserver;
 	#callback: (record: MutationRecord[], observer: MutationObserver) => void;
-	#records: MutationRecord[] = [];
+	#records: MutationRecord[] | null = [];
 	#immediate: NodeJS.Immediate | null = null;
 
 	/**
@@ -46,13 +46,19 @@ export default class MutationListener {
 	 * @param record Record.
 	 */
 	public report(record: MutationRecord): void {
+		if (!this.#records) {
+			return;
+		}
+
 		this.#records.push(record);
+
 		if (this.#immediate) {
 			this.#window.cancelAnimationFrame(this.#immediate);
 		}
+
 		this.#immediate = this.#window.requestAnimationFrame(() => {
 			const records = this.#records;
-			if (records.length > 0) {
+			if (records?.length > 0) {
 				this.#records = [];
 				this.#callback(records, this.#observer);
 			}
diff --git a/packages/happy-dom/test/mutation-observer/MutationObserver.test.ts b/packages/happy-dom/test/mutation-observer/MutationObserver.test.ts
index 3afc3a02a..095c02dd0 100644
--- a/packages/happy-dom/test/mutation-observer/MutationObserver.test.ts
+++ b/packages/happy-dom/test/mutation-observer/MutationObserver.test.ts
@@ -307,13 +307,40 @@ describe('MutationObserver', () => {
 			const observer = new MutationObserver((mutationRecords) => {
 				records = mutationRecords;
 			});
-			observer.observe(div, { attributes: true });
+			const span = document.createElement('span');
+			const text = document.createTextNode('old');
 
-			window.close();
+			span.appendChild(text);
+			div.appendChild(span);
 
-			div.setAttribute('attr', 'value');
+			document.body.appendChild(div);
 
-			await new Promise((resolve) => setTimeout(resolve, 1));
+			observer.observe(div, {
+				attributes: true,
+				childList: true,
+				subtree: true,
+				characterData: true,
+				attributeOldValue: true,
+				characterDataOldValue: true
+			});
+
+			text.textContent = 'new1';
+			div.setAttribute('attr', 'value1');
+
+			await Promise.all([
+				window.happyDOM.close(),
+				(async () => {
+					text.textContent = 'new2';
+					div.setAttribute('attr', 'value2');
+				})(),
+				new Promise((resolve) => setTimeout(resolve, 10))
+			]);
+
+			text.textContent = 'new3';
+			div.removeChild(span);
+			div.setAttribute('attr', 'value3');
+
+			await new Promise((resolve) => setTimeout(resolve, 10));
 
 			expect(records).toEqual([]);
 		});