packages/happy-dom/src/query-selector/QuerySelector.ts

@@ -16,6 +16,11 @@ type IDocumentPositionAndElement = {
 	element: IElement;
 };
 
+/**
+ * Invalid Selector RegExp.
+ */
+const INVALID_SELECTOR_REGEXP = /^[.#\[]?\d/;
+
 /**
  * Utility for query selection in an HTML element.
  *
@@ -35,14 +40,20 @@ export default class QuerySelector {
 	): INodeList<IElement> {
 		if (selector === '') {
 			throw new Error(
-				"Failed to execute 'querySelectorAll' on 'Element': The provided selector is empty."
+				`Failed to execute 'querySelectorAll' on '${node.constructor.name}': The provided selector is empty.`
 			);
 		}
 
 		if (selector === null || selector === undefined) {
 			return new NodeList<IElement>();
 		}
 
+		if (INVALID_SELECTOR_REGEXP.test(selector)) {
+			throw new Error(
+				`Failed to execute 'querySelectorAll' on '${node.constructor.name}': '${selector}' is not a valid selector.`
+			);
+		}
+
 		const groups = SelectorParser.getSelectorGroups(selector);
 		let matches: IDocumentPositionAndElement[] = [];
 
@@ -79,17 +90,23 @@ export default class QuerySelector {
 	public static querySelector(
 		node: IElement | IDocument | IDocumentFragment,
 		selector: string
-	): IElement {
+	): IElement | null {
 		if (selector === '') {
 			throw new Error(
-				"Failed to execute 'querySelector' on 'Element': The provided selector is empty."
+				`Failed to execute 'querySelector' on '${node.constructor.name}': The provided selector is empty.`
 			);
 		}
 
 		if (selector === null || selector === undefined) {
 			return null;
 		}
 
+		if (INVALID_SELECTOR_REGEXP.test(selector)) {
+			throw new Error(
+				`Failed to execute 'querySelector' on '${node.constructor.name}': '${selector}' is not a valid selector.`
+			);
+		}
+
 		for (const items of SelectorParser.getSelectorGroups(selector)) {
 			const match =
 				node[PropertySymbol.nodeType] === NodeTypeEnum.elementNode
@@ -112,12 +129,22 @@ export default class QuerySelector {
 	 * @returns Result.
 	 */
 	public static match(element: IElement, selector: string): ISelectorMatch | null {
+		if (!selector) {
+			return null;
+		}
+
 		if (selector === '*') {
 			return {
 				priorityWeight: 1
 			};
 		}
 
+		if (INVALID_SELECTOR_REGEXP.test(selector)) {
+			throw new Error(
+				`Failed to execute 'match' on '${element.constructor.name}': '${selector}' is not a valid selector.`
+			);
+		}
+
 		for (const items of SelectorParser.getSelectorGroups(selector)) {
 			const result = this.matchSelector(element, element, items.reverse());
 

packages/happy-dom/test/query-selector/QuerySelector.test.ts

@@ -975,6 +975,22 @@ describe('QuerySelector', () => {
 
 			expect(elements.length).toBe(0);
 		});
+
+		it('Throws an error when providing an invalid selector', () => {
+			const div = document.createElement('div');
+			expect(() => div.querySelectorAll('1')).toThrowError(
+				"Failed to execute 'querySelectorAll' on 'HTMLElement': '1' is not a valid selector."
+			);
+			expect(() => div.querySelectorAll('[1')).toThrowError(
+				"Failed to execute 'querySelectorAll' on 'HTMLElement': '[1' is not a valid selector."
+			);
+			expect(() => div.querySelectorAll('.1')).toThrowError(
+				"Failed to execute 'querySelectorAll' on 'HTMLElement': '.1' is not a valid selector."
+			);
+			expect(() => div.querySelectorAll('#1')).toThrowError(
+				"Failed to execute 'querySelectorAll' on 'HTMLElement': '#1' is not a valid selector."
+			);
+		});
 	});
 
 	describe('querySelector', () => {
@@ -1126,5 +1142,21 @@ describe('QuerySelector', () => {
 			expect(element === div.children[0]).toBe(true);
 			expect(element2 === div.children[0]).toBe(true);
 		});
+
+		it('Throws an error when providing an invalid selector', () => {
+			const div = document.createElement('div');
+			expect(() => div.querySelector('1')).toThrowError(
+				"Failed to execute 'querySelector' on 'HTMLElement': '1' is not a valid selector."
+			);
+			expect(() => div.querySelector('[1')).toThrowError(
+				"Failed to execute 'querySelector' on 'HTMLElement': '[1' is not a valid selector."
+			);
+			expect(() => div.querySelector('.1')).toThrowError(
+				"Failed to execute 'querySelector' on 'HTMLElement': '.1' is not a valid selector."
+			);
+			expect(() => div.querySelector('#1')).toThrowError(
+				"Failed to execute 'querySelector' on 'HTMLElement': '#1' is not a valid selector."
+			);
+		});
 	});
 });