From 8c23f992309eda75c0b914d9da6660a117cd393d Mon Sep 17 00:00:00 2001
From: dmitry-vakhnenko <33278950+dmitry-vakhnenko@users.noreply.github.com>
Date: Sun, 21 Jan 2018 00:59:16 +0300
Subject: [PATCH 1/5] Use native bind

Simple refactor bind function for easy revert.
Custom bind implementation performance is lower than native.

https://jsperf.com/vue-bind-perf
---
 src/shared/util.js | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/src/shared/util.js b/src/shared/util.js
index a0bc957ee93..1cea2897e0a 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -174,20 +174,10 @@ export const hyphenate = cached((str: string): string => {
 })
 
 /**
- * Simple bind, faster than native
+ * Bind funciton context
  */
 export function bind (fn: Function, ctx: Object): Function {
-  function boundFn (a) {
-    const l: number = arguments.length
-    return l
-      ? l > 1
-        ? fn.apply(ctx, arguments)
-        : fn.call(ctx, a)
-      : fn.call(ctx)
-  }
-  // record original fn length
-  boundFn._length = fn.length
-  return boundFn
+  return fn.bind(ctx)
 }
 
 /**

From 46965bed990888f0d6ea11e14c202d4c05f10ad3 Mon Sep 17 00:00:00 2001
From: dmitry-vakhnenko <33278950+dmitry-vakhnenko@users.noreply.github.com>
Date: Sun, 21 Jan 2018 02:23:15 +0300
Subject: [PATCH 2/5] use bind polyfill if Function.bind not exits

---
 src/shared/util.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/shared/util.js b/src/shared/util.js
index 1cea2897e0a..508eee2185e 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -177,6 +177,21 @@ export const hyphenate = cached((str: string): string => {
  * Bind funciton context
  */
 export function bind (fn: Function, ctx: Object): Function {
+  if(!Function.prototype.bind) {
+    function boundFn (a) {
+      const l = arguments.length
+      return l
+        ? l > 1
+          ? fn.apply(ctx, arguments)
+          : fn.call(ctx, a)
+        : fn.call(ctx)
+    }
+    // record original fn length
+    boundFn._length = fn.length
+    
+    return boundFn
+  }
+  
   return fn.bind(ctx)
 }
 

From 454a201f9961b13115921c882ea00c4f98ea9805 Mon Sep 17 00:00:00 2001
From: dmitry-vakhnenko <33278950+dmitry-vakhnenko@users.noreply.github.com>
Date: Sun, 21 Jan 2018 02:25:18 +0300
Subject: [PATCH 3/5] Update util.js

---
 src/shared/util.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/shared/util.js b/src/shared/util.js
index 508eee2185e..2ade6583308 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -174,7 +174,7 @@ export const hyphenate = cached((str: string): string => {
 })
 
 /**
- * Bind funciton context
+ * Bind function context
  */
 export function bind (fn: Function, ctx: Object): Function {
   if(!Function.prototype.bind) {

From 2a48f51a6bd1302557dcd50bad896ca6591af328 Mon Sep 17 00:00:00 2001
From: dmitry-vakhnenko <33278950+dmitry-vakhnenko@users.noreply.github.com>
Date: Mon, 22 Jan 2018 18:00:21 +0300
Subject: [PATCH 4/5] Update util.js

---
 src/shared/util.js | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/shared/util.js b/src/shared/util.js
index 2ade6583308..e62c166ef40 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -176,25 +176,26 @@ export const hyphenate = cached((str: string): string => {
 /**
  * Bind function context
  */
-export function bind (fn: Function, ctx: Object): Function {
-  if(!Function.prototype.bind) {
-    function boundFn (a) {
-      const l = arguments.length
-      return l
-        ? l > 1
-          ? fn.apply(ctx, arguments)
-          : fn.call(ctx, a)
-        : fn.call(ctx)
-    }
-    // record original fn length
-    boundFn._length = fn.length
-    
-    return boundFn
+function ownBind (fn: Function, ctx: Object): Function {
+  function boundFn (a) {
+    const l = arguments.length
+    return l
+      ? l > 1
+        ? fn.apply(ctx, arguments)
+        : fn.call(ctx, a)
+      : fn.call(ctx)
   }
-  
+
+  boundFn._length = fn.length
+  return boundFn
+}
+
+function nativeBind(fn: Function, ctx: Object): Function {
   return fn.bind(ctx)
 }
 
+export const bind = Function.prototype.bind ? nativeBind : ownBind
+
 /**
  * Convert an Array-like object to a real Array.
  */

From 368c5f9caf493d0657e863d24ab3049e454bfb1e Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Thu, 8 Mar 2018 10:07:13 -0500
Subject: [PATCH 5/5] Update util.js

---
 src/shared/util.js | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/shared/util.js b/src/shared/util.js
index e62c166ef40..3a7664b76e9 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -174,9 +174,13 @@ export const hyphenate = cached((str: string): string => {
 })
 
 /**
- * Bind function context
+ * Simple bind polyfill for environments that do not support it... e.g.
+ * PhantomJS 1.x. Technically we don't need this anymore since native bind is
+ * now more performant in most browsers, but removing it would be breaking for
+ * code that was able to run in PhantomJS 1.x, so this must be kept for
+ * backwards compatibility.
  */
-function ownBind (fn: Function, ctx: Object): Function {
+function polyfillBind (fn: Function, ctx: Object): Function {
   function boundFn (a) {
     const l = arguments.length
     return l
@@ -190,11 +194,13 @@ function ownBind (fn: Function, ctx: Object): Function {
   return boundFn
 }
 
-function nativeBind(fn: Function, ctx: Object): Function {
+function nativeBind (fn: Function, ctx: Object): Function {
   return fn.bind(ctx)
 }
 
-export const bind = Function.prototype.bind ? nativeBind : ownBind
+export const bind = Function.prototype.bind
+  ? nativeBind
+  : polyfillBind
 
 /**
  * Convert an Array-like object to a real Array.