Function diffElementNodes

src/diff/index.js:411–609

* Diff two virtual nodes representing DOM element * @param {PreactElement} dom The DOM element representing the virtual nodes * being diffed * @param {VNode} newVNode The new virtual node * @param {VNode} oldVNode The old virtual node * @param {object} globalContext The current context object

(
	dom,
	newVNode,
	oldVNode,
	globalContext,
	namespace,
	excessDomChildren,
	commitQueue,
	isHydrating,
	refQueue
)

 * @returns {PreactElement}
 */
function diffElementNodes(
	dom,
	newVNode,
	oldVNode,
	globalContext,
	namespace,
	excessDomChildren,
	commitQueue,
	isHydrating,
	refQueue
) {
	let oldProps = oldVNode.props || EMPTY_OBJ;
	let newProps = newVNode.props;
	let nodeType = /** @type {string} */ (newVNode.type);
	/** @type {any} */
	let i;
	/** @type {{ __html?: string }} */
	let newHtml;
	/** @type {{ __html?: string }} */
	let oldHtml;
	/** @type {ComponentChildren} */
	let newChildren;
	let value;
	let inputValue;
	let checked;

	// Tracks entering and exiting namespaces when descending through the tree.
	if (nodeType == 'svg') namespace = SVG_NAMESPACE;
	else if (nodeType == 'math') namespace = MATH_NAMESPACE;
	else if (!namespace) namespace = XHTML_NAMESPACE;

	if (excessDomChildren != NULL) {
		for (i = 0; i < excessDomChildren.length; i++) {
			value = excessDomChildren[i];

			// if newVNode matches an element in excessDomChildren or the `dom`
			// argument matches an element in excessDomChildren, remove it from
			// excessDomChildren so it isn't later removed in diffChildren
			if (
				value &&
				'setAttribute' in value == !!nodeType &&
				(nodeType ? value.localName == nodeType : value.nodeType == 3)
			) {
				dom = value;
				excessDomChildren[i] = NULL;
				break;
			}
		}
	}

	if (dom == NULL) {
		if (nodeType == NULL) {
			return document.createTextNode(newProps);
		}

		dom = document.createElementNS(
			namespace,
			nodeType,