fix(compiler-core): should pre-convert text nodes in all non-element cases

packages/compiler-core/src/transforms/transformText.ts

@@ -6,7 +6,8 @@ import {
   InterpolationNode,
   CompoundExpressionNode,
   createCallExpression,
-  CallExpression
+  CallExpression,
+  ElementTypes
 } from '../ast'
 import { CREATE_TEXT } from '../runtimeHelpers'
 import { PatchFlags, PatchFlagNames } from '@vue/shared'
@@ -53,9 +54,20 @@ export const transformText: NodeTransform = (node, context) => {
         }
       }
 
-      if (hasText && children.length > 1) {
+      if (
-        // when an element has mixed text/element children, convert text nodes
+        !hasText ||
-        // into createTextVNode(text) calls.
+        // if this is a plain element with a single text child, leave it as-is
+        // since the runtime has dedicated fast path for this by directly
+        // setting textContent of the element.
+        (node.type === NodeTypes.ELEMENT &&
+          node.tagType === ElementTypes.ELEMENT &&
+          children.length === 1)
+      ) {
+        return
+      }
+
+      // pre-convert text nodes into createTextVNode(text) calls to avoid
+      // runtime normalization.
       for (let i = 0; i < children.length; i++) {
         const child = children[i]
         if (isText(child) || child.type === NodeTypes.COMPOUND_EXPRESSION) {
@@ -84,5 +96,4 @@ export const transformText: NodeTransform = (node, context) => {
       }
     }
   }
-  }
 }