fix(dom): Remove all links as part of removeChild

which fixes weird side effects when trying to `appendChild` the same node later

lib/dom.js

@@ -591,48 +591,65 @@ function _onRemoveAttribute(doc,el,newAttr,remove){
 	}
 }
 
+/**
+ * Updates `el.childNodes` by either appending `newChild`
+ * or updating the indexed items, by iterating from `el.firstChild` over all `nextSibling`s
+ * and updating the `length` accordingly.
+ *
+ * @param {Document} doc
+ * @param {Node} el
+ * @param {Node} [newChild]
+ * @private
+ */
 function _onUpdateChild(doc,el,newChild){
 	if(doc && doc._inc){
 		doc._inc++;
 		//update childNodes
 		var cs = el.childNodes;
-		if(newChild){
+		if (newChild) {
 			cs[cs.length++] = newChild;
-		}else{
-			//console.log(1)
+		} else {
 			var child = el.firstChild;
 			var i = 0;
-			while(child){
+			while (child) {
 				cs[i++] = child;
-				child =child.nextSibling;
+				child = child.nextSibling;
 			}
 			cs.length = i;
+			delete cs[cs.length];
 		}
 	}
 }
 
 /**
- * attributes;
- * children;
- * 
- * writeable properties:
- * nodeValue,Attr:value,CharacterData:data
- * prefix
+ * Removes the connections between `parentNode` and `child`
+ * and any existing `child.previousSibling` or `child.nextSibling`.
+ *
+ * @see https://github.com/xmldom/xmldom/issues/135
+ * @see https://github.com/xmldom/xmldom/issues/145
+ *
+ * @param {Node} parentNode
+ * @param {Node} child
+ * @returns {Node} the child that was removed.
+ * @private
  */
 function _removeChild(parentNode,child){
 	var previous = child.previousSibling;
 	var next = child.nextSibling;
-	if(previous){
+	if (previous) {
 		previous.nextSibling = next;
-	}else{
-		parentNode.firstChild = next
+	} else {
+		parentNode.firstChild = next;
 	}
-	if(next){
+	if (next) {
 		next.previousSibling = previous;
-	}else{
+	} else {
 		parentNode.lastChild = previous;
 	}
-	_onUpdateChild(parentNode.ownerDocument,parentNode);
+	child.parentNode = null;
+	child.previousSibling = null;
+	child.nextSibling = null;
+	_onUpdateChild(parentNode.ownerDocument, parentNode);
 	return child;
 }
 /**
@@ -679,25 +696,20 @@ function _insertBefore(parentNode,newChild,nextChild){
 	return newChild;
 }
 function _appendSingleChild(parentNode,newChild){
-	var cp = newChild.parentNode;
-	if(cp){
-		var pre = parentNode.lastChild;
-		cp.removeChild(newChild);//remove and update
-		var pre = parentNode.lastChild;
+	if (newChild.parentNode) {
+		newChild.parentNode.removeChild(newChild);
 	}
-	var pre = parentNode.lastChild;
 	newChild.parentNode = parentNode;
-	newChild.previousSibling = pre;
+	newChild.previousSibling = parentNode.lastChild;
 	newChild.nextSibling = null;
-	if(pre){
-		pre.nextSibling = newChild;
-	}else{
+	if (newChild.previousSibling) {
+		newChild.previousSibling.nextSibling = newChild;
+	} else {
 		parentNode.firstChild = newChild;
 	}
 	parentNode.lastChild = newChild;
-	_onUpdateChild(parentNode.ownerDocument,parentNode,newChild);
+	_onUpdateChild(parentNode.ownerDocument, parentNode, newChild);
 	return newChild;
-	//console.log("__aa",parentNode.lastChild.nextSibling == null)
 }
 Document.prototype = {
 	//implementation : null,

test/dom/element.test.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const { DOMParser, DOMImplementation, XMLSerializer } = require('../../lib')
+const { Node } = require('../../lib/dom')
 
 describe('Document', () => {
 	// See: http://jsfiddle.net/bigeasy/ShcXP/1/
@@ -175,6 +176,38 @@ describe('Document', () => {
 		})
 	})
 
+	it('appendElement and removeElement', () => {
+		const dom = new DOMParser().parseFromString(`<root><A/><B/><C/></root>`)
+		const doc = dom.documentElement
+		const arr = []
+		while (doc.firstChild) {
+			const node = doc.removeChild(doc.firstChild)
+			arr.push(node)
+			expect(node.parentNode).toBeNull()
+			expect(node.previousSibling).toBeNull()
+			expect(node.nextSibling).toBeNull()
+			expect(node.ownerDocument).toBe(dom)
+			expect(doc.firstChild).not.toBe(node)
+			const expectedLength = 3 - arr.length
+			expect(doc.childNodes).toHaveLength(expectedLength)
+			expect(doc.childNodes.item(expectedLength)).toBeNull()
+		}
+		expect(arr).toHaveLength(3)
+		while (arr.length) {
+			const node = arr.shift()
+			expect(doc.appendChild(node)).toBe(node)
+			expect(node.parentNode).toBe(doc)
+			const expectedLength = 3 - arr.length
+			expect(doc.childNodes).toHaveLength(expectedLength)
+			expect(doc.childNodes.item(expectedLength - 1)).toBe(node)
+			if (expectedLength > 1) {
+				expect(node.previousSibling).not.toBeInstanceOf(Node)
+				expect(node.previousSibling.nextSibling).toBe(node)
+			}
+		}
+		expect(doc.childNodes.toString()).toBe(`<A/><B/><C/>`)
+	})
+
 	xit('nested append failed', () => {})
 
 	xit('self append failed', () => {})