diff --git a/packages/happy-dom/src/nodes/html-element/HTMLElement.ts b/packages/happy-dom/src/nodes/html-element/HTMLElement.ts
index 262eb88a5..a37ada029 100644
--- a/packages/happy-dom/src/nodes/html-element/HTMLElement.ts
+++ b/packages/happy-dom/src/nodes/html-element/HTMLElement.ts
@@ -251,10 +251,9 @@ export default class HTMLElement extends Element implements IHTMLElement {
},
deleteProperty: (dataset: { [key: string]: string }, key: string) => {
const name = 'data-' + DatasetUtility.camelCaseToKebab(key);
- const exists = !!attributes[name];
- delete attributes[name];
- delete dataset[key];
- return exists;
+ const result1 = delete attributes[name];
+ const result2 = delete dataset[key];
+ return result1 && result2;
},
ownKeys: (dataset: { [key: string]: string }) => {
// According to Mozilla we have to update the dataset object (target) to contain the same keys as what we return: