feat: v-memo

packages/runtime-core/src/vnode.ts

@@ -182,6 +182,9 @@ export interface VNode<
 
   // application root node only
   appContext: AppContext | null
+
+  // v-for memo
+  memo?: any[]
 }
 
 // Since v-if and v-for are the two possible ways node structure can dynamically
@@ -221,7 +224,7 @@ export function closeBlock() {
 // Only tracks when this value is > 0
 // We are not using a simple boolean because this value may need to be
 // incremented/decremented by nested usage of v-once (see below)
-let isBlockTreeEnabled = 1
+export let isBlockTreeEnabled = 1
 
 /**
  * Block tracking sometimes needs to be disabled, for example during the
@@ -692,7 +695,7 @@ export function normalizeVNode(child: VNodeChild): VNode {
 
 // optimized normalization for template-compiled render fns
 export function cloneIfMounted(child: VNode): VNode {
-  return child.el === null ? child : cloneVNode(child)
+  return child.el === null || child.memo ? child : cloneVNode(child)
 }
 
 export function normalizeChildren(vnode: VNode, children: unknown) {