feat: [#1373] Adds support for the :has pseudo selector

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

@@ -308,21 +308,43 @@ export default class SelectorItem {
 				}
 				return element.isConnected && element.id === hash.slice(1) ? { priorityWeight: 10 } : null;
 			case 'is':
-				let priorityWeight = 0;
+				let priorityWeightForIs = 0;
 				for (const selectorItem of pseudo.selectorItems) {
 					const match = selectorItem.match(element);
-					if (match) {
-						priorityWeight = match.priorityWeight;
+					if (match && priorityWeightForIs < match.priorityWeight) {
+						priorityWeightForIs = match.priorityWeight;
 					}
 				}
-				return priorityWeight ? { priorityWeight } : null;
+				return priorityWeightForIs ? { priorityWeight: priorityWeightForIs } : null;
 			case 'where':
 				for (const selectorItem of pseudo.selectorItems) {
 					if (selectorItem.match(element)) {
 						return { priorityWeight: 0 };
 					}
 				}
 				return null;
+			case 'has':
+				let priorityWeightForHas = 0;
+				if (pseudo.arguments.startsWith('+')) {
+					const nextSibling = element.nextElementSibling;
+					if (!nextSibling) {
+						return null;
+					}
+					for (const selectorItem of pseudo.selectorItems) {
+						const match = selectorItem.match(nextSibling);
+						if (match && priorityWeightForHas < match.priorityWeight) {
+							priorityWeightForHas = match.priorityWeight;
+						}
+					}
+				} else {
+					for (const selectorItem of pseudo.selectorItems) {
+						const match = this.matchChildOfElement(selectorItem, element);
+						if (match && priorityWeightForHas < match.priorityWeight) {
+							priorityWeightForHas = match.priorityWeight;
+						}
+					}
+				}
+				return priorityWeightForHas ? { priorityWeight: priorityWeightForHas } : null;
 			case 'focus':
 			case 'focus-visible':
 				return element[PropertySymbol.ownerDocument].activeElement === element
@@ -394,6 +416,29 @@ export default class SelectorItem {
 		return { priorityWeight };
 	}
 
+	/**
+	 * Matches a selector item against children of an element.
+	 *
+	 * @param selectorItem Selector item.
+	 * @param element Element.
+	 * @returns Result.
+	 */
+	private matchChildOfElement(
+		selectorItem: SelectorItem,
+		element: Element
+	): { priorityWeight: number } | null {
+		for (const child of element[PropertySymbol.elementArray]) {
+			const match = selectorItem.match(child);
+			if (match) {
+				return match;
+			}
+			const childMatch = this.matchChildOfElement(selectorItem, child);
+			if (childMatch) {
+				return childMatch;
+			}
+		}
+	}
+
 	/**
 	 * Returns the selector string.
 	 *

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

@@ -313,9 +313,8 @@ export default class SelectorParser {
 				};
 			case 'is':
 			case 'where':
-				const selectorGroups = this.getSelectorGroups(args, options);
 				const selectorItems = [];
-				for (const group of selectorGroups) {
+				for (const group of this.getSelectorGroups(args, options)) {
 					selectorItems.push(group[0]);
 				}
 				return {
@@ -324,6 +323,25 @@ export default class SelectorParser {
 					selectorItems,
 					nthFunction: null
 				};
+			case 'has':
+				const hasSelectorItems = [];
+
+				// 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,
+						options
+					)) {
+						hasSelectorItems.push(group[0]);
+					}
+				}
+
+				return {
+					name: lowerName,
+					arguments: args,
+					selectorItems: hasSelectorItems,
+					nthFunction: null
+				};
 			default:
 				return { name: lowerName, arguments: args, selectorItems: null, nthFunction: null };
 		}

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

@@ -1087,6 +1087,30 @@ describe('QuerySelector', () => {
 			expect(document.querySelectorAll(':focus')[0]).toBe(div);
 			expect(document.querySelectorAll(':focus-visible')[0]).toBe(div);
 		});
+
+		it('Returns element matching selector with CSS pseudo ":has()"', () => {
+			const container = document.createElement('div');
+			container.innerHTML = `
+                <span><video attr="value1"></video></span>
+                <span><b><video></video></b></span>
+                <video></video>
+                <h1></h1>
+                <h2></h2>
+            `;
+			expect(Array.from(container.querySelectorAll('span:has(video)'))).toEqual([
+				container.children[0],
+				container.children[1]
+			]);
+			expect(Array.from(container.querySelectorAll('span:has(video[attr="value1"])'))).toEqual([
+				container.children[0]
+			]);
+			expect(Array.from(container.querySelectorAll('span:has(+video)'))).toEqual([
+				container.children[1]
+			]);
+			expect(Array.from(container.querySelectorAll('h1:has(+h2)'))).toEqual([
+				container.children[3]
+			]);
+		});
 	});
 
 	describe('querySelector', () => {
@@ -1399,6 +1423,21 @@ describe('QuerySelector', () => {
 			expect(container.querySelector(':where(span[attr1="val,ue1"])')).toBe(null);
 		});
 
+		it('Returns element matching selector with CSS pseudo ":has()"', () => {
+			const container = document.createElement('div');
+			container.innerHTML = `
+                <span><video attr="value1"></video></span>
+                <span><b><video></video></b></span>
+                <video></video>
+                <h1></h1>
+                <h2></h2>
+            `;
+			expect(container.querySelector('span:has(video)')).toBe(container.children[0]);
+			expect(container.querySelector('span:has(video[attr="value1"])')).toBe(container.children[0]);
+			expect(container.querySelector('span:has(+video)')).toBe(container.children[1]);
+			expect(container.querySelector('h1:has(+h2)')).toBe(container.children[3]);
+		});
+
 		it('Remove new line from selector and trim selector before parse', () => {
 			const container = document.createElement('div');
 
@@ -1540,6 +1579,22 @@ describe('QuerySelector', () => {
 			expect(element.matches(':where(div)')).toBe(false);
 		});
 
+		it('Returns element matching selector with CSS pseudo ":has()"', () => {
+			const container = document.createElement('div');
+			container.innerHTML = `
+                <span><video attr="value1"></video></span>
+                <span><b><video></video></b></span>
+                <video></video>
+                <h1></h1>
+                <h2></h2>
+            `;
+			expect(container.children[0].matches('span:has(video)')).toBe(true);
+			expect(container.children[0].matches(':has(video[attr="value1"])')).toBe(true);
+			expect(container.children[1].matches('span:has(+video)')).toBe(true);
+			expect(container.children[3].matches(':has(+h2)')).toBe(true);
+			expect(container.children[3].matches('h1:has(+h2)')).toBe(true);
+		});
+
 		it('Returns true for selector with CSS pseudo ":focus" and ":focus-visible"', () => {
 			document.body.innerHTML = QuerySelectorHTML;
 			const span = <HTMLElement>document.querySelector('span.class1');