Rework children diffing to run in multiple phases

jsx-runtime/src/index.js

@@ -53,6 +53,8 @@ function createVNode(type, props, key, isStaticChildren, __source, __self) {
 		_hydrating: null,
 		constructor: undefined,
 		_original: --vnodeId,
+		_flags: 0,
+		_index: -1,
 		__source,
 		__self
 	};

mangle.json

@@ -54,6 +54,10 @@
       "$_dom": "__e",
       "$_hydrating": "__h",
       "$_component": "__c",
+      "$_flags": "__u",
+      "$_insert": "__r",
+      "$_matched": "__s",
+      "$_index": "__i",
       "$__html": "__html",
       "$_parent": "__",
       "$_pendingError": "__E",

src/component.js

@@ -103,7 +103,7 @@ export function getDomSibling(vnode, childIndex) {
 			// Since updateParentDomPointers keeps _dom pointer correct,
 			// we can rely on _dom to tell us if this subtree contains a
 			// rendered DOM node, and what the first rendered DOM node is
-			return sibling._nextDom || sibling._dom;
+			return sibling._dom;
 		}
 	}
 

src/constants.js

@@ -1,4 +1,14 @@
+/** Indicates that this node needs to be inserted while patching children */
+export const INSERT_VNODE = 1 << 16;
+export const MATCHED = 1 << 17;
+
+/** Reset all mode flags */
+export const RESET_MODE = ~(INSERT_VNODE | MATCHED);
+
 export const EMPTY_OBJ = {};
+export const EMPTY_VNODE = /** @type {import('./internal').VNode} */ (
+	EMPTY_OBJ
+);
 export const EMPTY_ARR = [];
 export const IS_NON_DIMENSIONAL =
 	/acit|ex(?:s|g|n|p|$)|rph|grid|ows|mnc|ntw|ine[ch]|zoo|^ord|itera/i;

src/create-element.js

@@ -72,7 +72,11 @@ export function createVNode(type, props, key, ref, original) {
 		_component: null,
 		_hydrating: null,
 		constructor: undefined,
-		_original: original == null ? ++vnodeId : original
+		_original: original == null ? ++vnodeId : original,
+		// TODO: Consolidate new VNode fields and add mangle.json entries for new
+		// ones that stay
+		_flags: 0,
+		_index: -1
 	};
 
 	// Only invoke the vnode hook if this was *not* a direct copy: