From 5abfe0274d7845db499eb8997507f7f3f6891b8a Mon Sep 17 00:00:00 2001
From: HcySunYang <HcySunYang@outlook.com>
Date: Sun, 19 Jul 2020 23:41:58 +0800
Subject: [PATCH 1/2] fix(compiler-core): event handler of Multi-line writing
 should be processed correctly

---
 .../__tests__/transforms/vOn.spec.ts          | 50 +++++++++++++++++++
 packages/compiler-core/src/transforms/vOn.ts  |  2 +-
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/packages/compiler-core/__tests__/transforms/vOn.spec.ts b/packages/compiler-core/__tests__/transforms/vOn.spec.ts
index 873734226ab..7051b95597e 100644
--- a/packages/compiler-core/__tests__/transforms/vOn.spec.ts
+++ b/packages/compiler-core/__tests__/transforms/vOn.spec.ts
@@ -271,6 +271,56 @@ describe('compiler: transform v-on', () => {
     })
   })
 
+  test('should NOT wrap as function if expression is already function expression (Multi-line writing)', () => {
+    const { node } = parseWithVOn(
+      `<div @click="
+      $event => {
+        foo($event)
+      }
+    "/>`
+    )
+    expect((node.codegenNode as VNodeCall).props).toMatchObject({
+      properties: [
+        {
+          key: { content: `onClick` },
+          value: {
+            type: NodeTypes.SIMPLE_EXPRESSION,
+            content: `
+      $event => {
+        foo($event)
+      }
+    `
+          }
+        }
+      ]
+    })
+  })
+
+  test('should NOT wrap as function if expression is already function expression (Multi-line writing + function keyword)', () => {
+    const { node } = parseWithVOn(
+      `<div @click="
+      function($event) {
+        foo($event)
+      }
+    "/>`
+    )
+    expect((node.codegenNode as VNodeCall).props).toMatchObject({
+      properties: [
+        {
+          key: { content: `onClick` },
+          value: {
+            type: NodeTypes.SIMPLE_EXPRESSION,
+            content: `
+      function($event) {
+        foo($event)
+      }
+    `
+          }
+        }
+      ]
+    })
+  })
+
   test('should NOT wrap as function if expression is complex member expression', () => {
     const { node } = parseWithVOn(`<div @click="a['b' + c]"/>`)
     expect((node.codegenNode as VNodeCall).props).toMatchObject({
diff --git a/packages/compiler-core/src/transforms/vOn.ts b/packages/compiler-core/src/transforms/vOn.ts
index c577d52d4cf..75759708bd3 100644
--- a/packages/compiler-core/src/transforms/vOn.ts
+++ b/packages/compiler-core/src/transforms/vOn.ts
@@ -16,7 +16,7 @@ import { validateBrowserExpression } from '../validateExpression'
 import { isMemberExpression, hasScopeRef } from '../utils'
 import { CAPITALIZE } from '../runtimeHelpers'
 
-const fnExpRE = /^([\w$_]+|\([^)]*?\))\s*=>|^function(?:\s+[\w$]+)?\s*\(/
+const fnExpRE = /^\s*([\w$_]+|\([^)]*?\))\s*=>|^\s*function(?:\s+[\w$]+)?\s*\(/
 
 export interface VOnDirectiveNode extends DirectiveNode {
   // v-on without arg is handled directly in ./transformElements.ts due to it affecting

From a797c7d3dcad05ff5f41a8a0eea86b609942e686 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Sun, 19 Jul 2020 11:48:05 -0400
Subject: [PATCH 2/2] Update vOn.spec.ts

---
 packages/compiler-core/__tests__/transforms/vOn.spec.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/compiler-core/__tests__/transforms/vOn.spec.ts b/packages/compiler-core/__tests__/transforms/vOn.spec.ts
index 7051b95597e..19c44c3daee 100644
--- a/packages/compiler-core/__tests__/transforms/vOn.spec.ts
+++ b/packages/compiler-core/__tests__/transforms/vOn.spec.ts
@@ -271,7 +271,7 @@ describe('compiler: transform v-on', () => {
     })
   })
 
-  test('should NOT wrap as function if expression is already function expression (Multi-line writing)', () => {
+  test('should NOT wrap as function if expression is already function expression (with newlines)', () => {
     const { node } = parseWithVOn(
       `<div @click="
       $event => {
@@ -296,7 +296,7 @@ describe('compiler: transform v-on', () => {
     })
   })
 
-  test('should NOT wrap as function if expression is already function expression (Multi-line writing + function keyword)', () => {
+  test('should NOT wrap as function if expression is already function expression (with newlines + function keyword)', () => {
     const { node } = parseWithVOn(
       `<div @click="
       function($event) {