From 5bfd8cfdd9d4e123dac3962016fd6c1c2757aab0 Mon Sep 17 00:00:00 2001
From: Anton Korzunov <thekashey@gmail.com>
Date: Mon, 4 Jun 2018 21:27:02 +1000
Subject: [PATCH] Dont reload function properties, revert #949, fixes #995,
 #978, #969, #984

---
 src/proxy/inject.js            | 17 +++++------
 test/proxy/consistency.test.js | 53 +++++++++++++++++++++++++++++-----
 2 files changed, 54 insertions(+), 16 deletions(-)

diff --git a/src/proxy/inject.js b/src/proxy/inject.js
index 94ad20957..834a97edb 100644
--- a/src/proxy/inject.js
+++ b/src/proxy/inject.js
@@ -81,12 +81,13 @@ function mergeComponents(
 
         const nextString = String(nextAttr)
         const injectedBefore = injectedMembers[key]
-        const isFunction =
-          nextString.indexOf('function') >= 0 || nextString.indexOf('=>') >= 0
+        const isArrow = nextString.indexOf('=>') >= 0
+        const isFunction = nextString.indexOf('function') >= 0 || isArrow
+        const referToThis = nextString.indexOf('this') >= 0
         if (
           nextString !== String(prevAttr) ||
           (injectedBefore && nextString !== String(injectedBefore)) ||
-          isFunction
+          (isArrow && referToThis)
         ) {
           if (!hasRegenerate) {
             if (!isFunction) {
@@ -150,15 +151,13 @@ function inject(target, currentGeneration, injectedMembers) {
     Object.keys(injectedMembers).forEach(key => {
       try {
         if (hasRegenerate) {
+          const usedThis =
+            String(injectedMembers[key]).match(/_this([\d])/gi) || []
           target[REGENERATE_METHOD](
             key,
             `(function REACT_HOT_LOADER_SANDBOX () {
-          var _this  = this; // common babel transpile
-          var _this2 = this; // common babel transpile
-          var _this3 = this; // common babel transpile
-          var _this4 = this; // common babel transpile
-          var _this5 = this; // common babel transpile
-          var _this6 = this; // common babel transpile
+          ${usedThis.map(name => `var ${name} = this;`)}
+
           return ${injectedMembers[key]};
           }).call(this)`,
           )
diff --git a/test/proxy/consistency.test.js b/test/proxy/consistency.test.js
index bc6b90b43..c2ee3484e 100644
--- a/test/proxy/consistency.test.js
+++ b/test/proxy/consistency.test.js
@@ -268,14 +268,35 @@ describe('consistency', () => {
         /* eslint-enable */
       })
 
-      it('should reflect external dependencies', () => {
+      it('should reflect external dependencies(broken, regression)', () => {
         /* eslint-disable */
         const externalValue = 42
+        let gen = 0
+        const generator2 = () => {
+          const g = gen++
+          return () => g
+        }
+        const generator3 = () => {
+          const g = gen++
+          return () => g
+        }
         class BaseClass extends React.Component {
-          arrow = () => externalValue
+          secret1 = 1
+          secret2 = generator2()
+          secret3 = generator3()
+          arrow1 = () => externalValue
+          arrow2 = () => this.secret1 + externalValue
 
           render() {
-            return this.arrow()
+            return (
+              this.arrow1() +
+              ':' +
+              this.arrow2() +
+              ':' +
+              this.secret2() +
+              ':' +
+              this.secret3()
+            )
           }
 
           __reactstandin__regenerateByEval(key, code) {
@@ -286,15 +307,27 @@ describe('consistency', () => {
         const proxy = createProxy(BaseClass)
         const Proxy = proxy.get()
         const instance = new Proxy()
-        expect(instance.render()).toBe(42)
+        expect(instance.render()).toBe(42 + ':' + 43 + ':' + 0 + ':' + 1)
 
         {
           const externalValue = 24
           class Update1Class extends React.Component {
-            arrow = () => externalValue
+            secret = 1
+            secret2 = generator2()
+            secret3 = generator3()
+            arrow1 = () => externalValue
+            arrow2 = () => this.secret1 + externalValue
 
             render() {
-              return this.arrow()
+              return (
+                this.arrow1() +
+                ':' +
+                this.arrow2() +
+                ':' +
+                this.secret2() +
+                ':' +
+                this.secret3()
+              )
             }
 
             __reactstandin__regenerateByEval(key, code) {
@@ -306,7 +339,13 @@ describe('consistency', () => {
         }
         /* eslint-enable */
 
-        expect(instance.render()).toBe(24)
+        // Arrow1 function refer to external variable
+        // Will not be updated
+        // while Arrow2 function will
+
+        // secret 3 should not be regenrated
+        // secret 4(this inside) should be regenrated
+        expect(instance.render()).toMatch(/([\d]+):25:0:1/)
       })
 
       it('should stand-for all class members', () => {