From a3601e9fa73d10f524ed3bdf3ae44df8847c1230 Mon Sep 17 00:00:00 2001
From: ysj16 <504427021@qq.com>
Date: Fri, 20 Mar 2020 23:29:44 +0800
Subject: [PATCH] perf(transform-vif): don't need to createBlock for a
 component (#853)

---
 .../__tests__/transforms/vIf.spec.ts          | 19 ++++++++++++++++++-
 packages/compiler-core/src/transforms/vIf.ts  |  7 ++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/packages/compiler-core/__tests__/transforms/vIf.spec.ts b/packages/compiler-core/__tests__/transforms/vIf.spec.ts
index 35de11686..0513ff4e3 100644
--- a/packages/compiler-core/__tests__/transforms/vIf.spec.ts
+++ b/packages/compiler-core/__tests__/transforms/vIf.spec.ts
@@ -12,7 +12,8 @@ import {
   SimpleExpressionNode,
   ConditionalExpression,
   IfConditionalExpression,
-  VNodeCall
+  VNodeCall,
+  ElementTypes
 } from '../../src/ast'
 import { ErrorCodes } from '../../src/errors'
 import { CompilerOptions, generate } from '../../src'
@@ -77,6 +78,22 @@ describe('compiler: v-if', () => {
       expect(node.branches[0].children[2].type).toBe(NodeTypes.ELEMENT)
       expect((node.branches[0].children[2] as ElementNode).tag).toBe(`p`)
     })
+  
+    test('component v-if', () => {
+      const { node } = parseWithIfTransform(`<Component v-if="ok"></Component>`)
+      expect(node.type).toBe(NodeTypes.IF)
+      expect(node.branches.length).toBe(1)
+      expect((node.branches[0].children[0] as ElementNode).tag).toBe(
+        `Component`
+      )
+      expect((node.branches[0].children[0] as ElementNode).tagType).toBe(
+        ElementTypes.COMPONENT
+      )
+      expect(
+        ((node.branches[0].children[0] as ElementNode)!
+          .codegenNode as VNodeCall)!.isBlock
+      ).toBe(false)
+    })
 
     test('v-if + v-else', () => {
       const { node } = parseWithIfTransform(`<div v-if="ok"/><p v-else/>`)
diff --git a/packages/compiler-core/src/transforms/vIf.ts b/packages/compiler-core/src/transforms/vIf.ts
index 5394cb8fd..cb0d6bd38 100644
--- a/packages/compiler-core/src/transforms/vIf.ts
+++ b/packages/compiler-core/src/transforms/vIf.ts
@@ -212,7 +212,12 @@ function createChildrenCodegenNode(
     const vnodeCall = (firstChild as ElementNode)
       .codegenNode as BlockCodegenNode
     // Change createVNode to createBlock.
-    if (vnodeCall.type === NodeTypes.VNODE_CALL) {
+    if (
+      vnodeCall.type === NodeTypes.VNODE_CALL &&
+      // component vnodes are always tracked and its children are
+      // compiled into slots so no need to make it a block
+      (firstChild as ElementNode).tagType !== ElementTypes.COMPONENT
+    ) {
       vnodeCall.isBlock = true
       helper(OPEN_BLOCK)
       helper(CREATE_BLOCK)