packages/happy-dom/src/custom-element/CustomElementRegistry.ts

@@ -2,6 +2,8 @@ import DOMException from '../exception/DOMException.js';
 import * as PropertySymbol from '../PropertySymbol.js';
 import HTMLElement from '../nodes/html-element/HTMLElement.js';
 import Node from '../nodes/node/Node.js';
+import IBrowserWindow from '../window/IBrowserWindow.js';
+import NamespaceURI from '../config/NamespaceURI.js';
 
 /**
  * Custom elements registry.
@@ -12,6 +14,16 @@ export default class CustomElementRegistry {
 	} = {};
 	public [PropertySymbol.registedClass]: Map<typeof HTMLElement, string> = new Map();
 	public [PropertySymbol.callbacks]: { [k: string]: (() => void)[] } = {};
+	#window: IBrowserWindow;
+
+	/**
+	 * Constructor.
+	 *
+	 * @param window Window.
+	 */
+	constructor(window: IBrowserWindow) {
+		this.#window = window;
+	}
 
 	/**
 	 * Defines a custom element class.
@@ -44,6 +56,31 @@ export default class CustomElementRegistry {
 			);
 		}
 
+		const tagName = name.toUpperCase();
+
+		elementClass[PropertySymbol.ownerDocument] = this.#window.document;
+
+		Object.defineProperty(elementClass.prototype, 'localName', {
+			configurable: true,
+			get: function () {
+				return this[PropertySymbol.localName] || name;
+			}
+		});
+
+		Object.defineProperty(elementClass.prototype, 'tagName', {
+			configurable: true,
+			get: function () {
+				return this[PropertySymbol.tagName] || tagName;
+			}
+		});
+
+		Object.defineProperty(elementClass.prototype, 'namespaceURI', {
+			configurable: true,
+			get: function () {
+				return this[PropertySymbol.namespaceURI] || NamespaceURI.html;
+			}
+		});
+
 		this[PropertySymbol.registry][name] = {
 			elementClass,
 			extends: options && options.extends ? options.extends.toLowerCase() : null
@@ -113,6 +150,18 @@ export default class CustomElementRegistry {
 		return this[PropertySymbol.registedClass].get(elementClass) || null;
 	}
 
+	/**
+	 * Destroys the registry.
+	 */
+	public [PropertySymbol.destroy](): void {
+		for (const entity of Object.values(this[PropertySymbol.registry])) {
+			entity.elementClass[PropertySymbol.ownerDocument] = null;
+		}
+		this[PropertySymbol.registry] = {};
+		this[PropertySymbol.registedClass] = new Map();
+		this[PropertySymbol.callbacks] = {};
+	}
+
 	/**
 	 * Validates the correctness of custom element tag names.
 	 *

packages/happy-dom/src/nodes/document/Document.ts

@@ -1122,7 +1122,7 @@ export default class Document extends Node implements IDocument {
 			];
 
 		if (customElement) {
-			const element = NodeFactory.createNode<IHTMLElement>(this, customElement.elementClass);
+			const element = new customElement.elementClass();
 			element[PropertySymbol.tagName] = qualifiedName.toUpperCase();
 			element[PropertySymbol.localName] = qualifiedName;
 			element[PropertySymbol.namespaceURI] = namespaceURI;

packages/happy-dom/src/nodes/node/Node.ts

@@ -297,7 +297,7 @@ export default class Node extends EventTarget implements INode {
 	 * @param otherNode Node to test with.
 	 * @returns "true" if this node contains the other node.
 	 */
-	public contains(otherNode: INode | undefined): boolean {
+	public contains(otherNode: INode): boolean {
 		if (otherNode === undefined) {
 			return false;
 		}

packages/happy-dom/src/window/BrowserWindow.ts

@@ -520,7 +520,7 @@ export default class BrowserWindow extends EventTarget implements IBrowserWindow
 
 		this.#browserFrame = browserFrame;
 
-		this.customElements = new CustomElementRegistry();
+		this.customElements = new CustomElementRegistry(this);
 		this.navigator = new Navigator(this);
 		this.history = new History();
 		this.screen = new Screen();
@@ -1274,6 +1274,10 @@ export default class BrowserWindow extends EventTarget implements IBrowserWindow
 			this.document.removeChild(node);
 		}
 
+		if (this.customElements[PropertySymbol.destroy]) {
+			this.customElements[PropertySymbol.destroy]();
+		}
+
 		this.document[PropertySymbol.activeElement] = null;
 		this.document[PropertySymbol.nextActiveElement] = null;
 		this.document[PropertySymbol.currentScript] = null;

packages/happy-dom/test/custom-element/CustomElementRegistry.test.ts

@@ -6,6 +6,7 @@ import Window from '../../src/window/Window.js';
 import DOMException from '../../src/exception/DOMException.js';
 import { beforeEach, describe, it, expect } from 'vitest';
 import * as PropertySymbol from '../../src/PropertySymbol.js';
+import NamespaceURI from '../../src/config/NamespaceURI.js';
 
 describe('CustomElementRegistry', () => {
 	let customElements;
@@ -15,7 +16,7 @@ describe('CustomElementRegistry', () => {
 	beforeEach(() => {
 		window = new Window();
 		document = window.document;
-		customElements = new CustomElementRegistry();
+		customElements = new CustomElementRegistry(window);
 		CustomElement.observedAttributesCallCount = 0;
 	});
 
@@ -37,6 +38,16 @@ describe('CustomElementRegistry', () => {
 			expect(customElements[PropertySymbol.registry]['custom-element'].extends).toBe('ul');
 		});
 
+		it('Can construct CustomElement instance using "new".', () => {
+			customElements.define('custom-element', CustomElement);
+			const customElement = new CustomElement();
+			expect(customElement).toBeInstanceOf(CustomElement);
+			expect(customElement.ownerDocument).toBe(document);
+			expect(customElement.localName).toBe('custom-element');
+			expect(customElement.tagName).toBe('CUSTOM-ELEMENT');
+			expect(customElement.namespaceURI).toBe(NamespaceURI.html);
+		});
+
 		it('Throws an error if tag name does not contain "-".', () => {
 			expect(() => customElements.define('element', CustomElement)).toThrow(
 				new DOMException(