diff --git a/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts b/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts
index 11409bfca..c7d90faec 100644
--- a/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts
+++ b/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts
@@ -57,7 +57,7 @@ export default class CookieStringUtility {
 					cookie.domain = value;
 					break;
 				case 'path':
-					cookie.path = value.startsWith('/') ? value : `/${value}`;
+					cookie.path = value[0] === '/' ? value : `/${value}`;
 					break;
 				case 'httponly':
 					cookie.httpOnly = true;
diff --git a/packages/happy-dom/src/css/utilities/CSSParser.ts b/packages/happy-dom/src/css/utilities/CSSParser.ts
index c8b31baab..c9f474a4c 100644
--- a/packages/happy-dom/src/css/utilities/CSSParser.ts
+++ b/packages/happy-dom/src/css/utilities/CSSParser.ts
@@ -88,7 +88,7 @@ export default class CSSParser {
 					newRule.parentStyleSheet = parentStyleSheet;
 					cssRules.push(newRule);
 					parentRule = newRule;
-				} else if (selectorText.startsWith('@')) {
+				} else if (selectorText[0] === '@') {
 					// Unknown rule.
 					// We will create a new rule to let it grab its content, but we will not add it to the cssRules array.
 					const newRule = new CSSRule(PropertySymbol.illegalConstructor, window);
diff --git a/packages/happy-dom/src/nodes/html-hyperlink-element/HTMLHyperlinkElementUtility.ts b/packages/happy-dom/src/nodes/html-hyperlink-element/HTMLHyperlinkElementUtility.ts
index f5f85e3a4..a923e0f03 100644
--- a/packages/happy-dom/src/nodes/html-hyperlink-element/HTMLHyperlinkElementUtility.ts
+++ b/packages/happy-dom/src/nodes/html-hyperlink-element/HTMLHyperlinkElementUtility.ts
@@ -299,7 +299,7 @@ export default class HTMLHyperlinkElementUtility {
 	 */
 	public getHash(): string {
 		const href = this.element.getAttribute('href');
-		if (href.startsWith('#')) {
+		if (href[0] === '#') {
 			return href;
 		}
 		let url: URL;
diff --git a/packages/happy-dom/src/query-selector/SelectorItem.ts b/packages/happy-dom/src/query-selector/SelectorItem.ts
index 5c407543b..81b7cdf1f 100644
--- a/packages/happy-dom/src/query-selector/SelectorItem.ts
+++ b/packages/happy-dom/src/query-selector/SelectorItem.ts
@@ -330,7 +330,7 @@ export default class SelectorItem {
 				return null;
 			case 'has':
 				let priorityWeightForHas = 0;
-				if (pseudo.arguments.startsWith('+')) {
+				if (pseudo.arguments[0] === '+') {
 					const nextSibling = element.nextElementSibling;
 					if (!nextSibling) {
 						return null;
diff --git a/packages/happy-dom/src/query-selector/SelectorParser.ts b/packages/happy-dom/src/query-selector/SelectorParser.ts
index eb960dcd1..88590a45f 100644
--- a/packages/happy-dom/src/query-selector/SelectorParser.ts
+++ b/packages/happy-dom/src/query-selector/SelectorParser.ts
@@ -329,7 +329,7 @@ export default class SelectorParser {
 				// The ":has()" pseudo selector doesn't allow for it to be nested inside another ":has()" pseudo selector, as it can lead to cyclic querying.
 				if (!args.includes(':has(')) {
 					for (const group of this.getSelectorGroups(
-						args.startsWith('+') ? args.replace('+', '') : args,
+						args[0] === '+' ? args.replace('+', '') : args,
 						options
 					)) {
 						hasSelectorItems.push(group[0]);