fix: [#1689] HTMLElement.dataset should return undefined for properti…

…es not found (#1738)
capricorn86 · Feb 24, 2025 · 33f1beb · 33f1beb
1 parent 6c5e0f9
commit 33f1beb
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Showing 4 changed files with 19 additions and 3 deletions.
diff --git a/packages/happy-dom/src/dom/DOMStringMap.ts b/packages/happy-dom/src/dom/DOMStringMap.ts
@@ -25,11 +25,11 @@ export default class DOMStringMap {
 		// Documentation for Proxy:
 		// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy
 		return new Proxy(this, {
-			get(_target, property: string): string {
+			get(_target, property: string): string | void {
 				const attribute = element.getAttribute(
 					'data-' + DOMStringMapUtility.camelCaseToKebab(property)
 				);
-				if (attribute) {
+				if (attribute !== null) {
 					return attribute;
 				}
 			},

diff --git a/packages/happy-dom/src/nodes/element/Element.ts b/packages/happy-dom/src/nodes/element/Element.ts
@@ -741,7 +741,7 @@ export default class Element
 	 *
 	 * @param name Name.
 	 */
-	public getAttribute(name: string): string {
+	public getAttribute(name: string): string | null {
 		const attribute = this[PropertySymbol.attributes].getNamedItem(name);
 		if (attribute) {
 			return attribute[PropertySymbol.value];

diff --git a/packages/happy-dom/test/nodes/element/Element.test.ts b/packages/happy-dom/test/nodes/element/Element.test.ts
@@ -1774,6 +1774,13 @@ describe('Element', () => {
 		});
 	});
 
+	describe('getAttribute()', () => {
+		it('Returns null when cannot find attribute.', () => {
+			element.setAttribute('key2', '');
+			expect(element.getAttribute('random')).toEqual(null);
+		});
+	});
+
 	describe('getAttributeNames()', () => {
 		it('Returns attribute names.', () => {
 			element.setAttributeNS(NAMESPACE_URI, 'global:local1', 'value1');

diff --git a/packages/happy-dom/test/nodes/html-element/HTMLElement.test.ts b/packages/happy-dom/test/nodes/html-element/HTMLElement.test.ts
@@ -334,6 +334,15 @@ describe('HTMLElement', () => {
 			const button = <HTMLElement>main.querySelector('button');
 			expect(button.closest('[data-test]')).toBe(div);
 		});
+
+		it('Handles empty string values correctly', () => {
+			element.setAttribute('data-test-empty', '');
+			const dataset = element.dataset;
+			expect(dataset.testEmpty).toBe('');
+			expect(dataset.nonExistentKey).toBeUndefined();
+			dataset.testEmptyAlso = '';
+			expect(dataset.testEmptyAlso).toBe('');
+		});
 	});
 
 	describe('get dir()', () => {