chore: [#1615] Continues on implementation

packages/happy-dom/src/html-parser/HTMLParser.ts

@@ -453,6 +453,7 @@ export default class HTMLParser {
 					parentConfig.moveForbiddenDescendant &&
 					!parentConfig.moveForbiddenDescendant.exclude.includes(lowerTagName)
 				) {
+					// We add the element before the first element that is not forbidden.
 					let before: Node | null = this.currentNode;
 					while (before) {
 						if (
@@ -471,6 +472,7 @@ export default class HTMLParser {
 					if (before && before.parentNode) {
 						before.parentNode.insertBefore(this.nextElement, before);
 					} else {
+						// If there is no element that is not forbidden, we append the element
 						before.appendChild(this.nextElement);
 					}
 					this.startTagIndex = this.markupRegExp.lastIndex;

packages/happy-dom/test/nodes/html-element/HTMLElement.test.ts

@@ -565,18 +565,17 @@ describe('HTMLElement', () => {
 			element.appendChild(child1);
 			element.appendChild(child2);
 
-			const rootNode = (document.body[PropertySymbol.rootNode] = document.createElement('div'));
-			const formNode = (document.body[PropertySymbol.formNode] = document.createElement('form'));
-			const selectNode = (document.body[PropertySymbol.selectNode] =
-				document.createElement('select'));
-			const textAreaNode = (document.body[PropertySymbol.textAreaNode] =
-				document.createElement('textarea'));
-
 			document.body.appendChild(element);
 
 			const attribute1 = document.createAttribute('test');
 			attribute1.value = 'test';
 			element.attributes.setNamedItem(attribute1);
+
+			const rootNode = (element[PropertySymbol.rootNode] = document.createElement('div'));
+			const formNode = (element[PropertySymbol.formNode] = document.createElement('form'));
+			const selectNode = (element[PropertySymbol.selectNode] = document.createElement('select'));
+			const textAreaNode = (element[PropertySymbol.textAreaNode] =
+				document.createElement('textarea'));
 			const mutationListeners = element[PropertySymbol.mutationListeners];
 			const isValue = (element[PropertySymbol.isValue] = 'test');
 
@@ -592,10 +591,14 @@ describe('HTMLElement', () => {
 
 			expect(customElement.childNodes.length).toBe(2);
 			expect(customElement.childNodes[0]).toBe(child1);
+			expect(customElement.childNodes[0].parentNode).toBe(customElement);
 			expect(customElement.childNodes[1]).toBe(child2);
+			expect(customElement.childNodes[1].parentNode).toBe(customElement);
 			expect(customElement.children.length).toBe(2);
 			expect(customElement.children[0]).toBe(child1);
+			expect(customElement.children[0].parentNode).toBe(customElement);
 			expect(customElement.children[1]).toBe(child2);
+			expect(customElement.children[1].parentNode).toBe(customElement);
 			expect(customElement[PropertySymbol.rootNode] === rootNode).toBe(true);
 			expect(customElement[PropertySymbol.formNode] === formNode).toBe(true);
 			expect(customElement[PropertySymbol.selectNode] === selectNode).toBe(true);