From 50c81d5fe68096fec9e4c5ff6c6cee73cd07704e Mon Sep 17 00:00:00 2001
From: Ben Alpert <balpert@fb.com>
Date: Wed, 25 Nov 2015 18:23:31 -0800
Subject: [PATCH] Make createClass 10-15% faster on complex specs

---
 src/isomorphic/classic/class/ReactClass.js | 33 +++++++++++-----------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/src/isomorphic/classic/class/ReactClass.js b/src/isomorphic/classic/class/ReactClass.js
index c606d625c2..441f3484f1 100644
--- a/src/isomorphic/classic/class/ReactClass.js
+++ b/src/isomorphic/classic/class/ReactClass.js
@@ -414,7 +414,7 @@ function validateTypeDef(Constructor, typeDef, location) {
   }
 }
 
-function validateMethodOverride(proto, name) {
+function validateMethodOverride(isAlreadyDefined, name) {
   var specPolicy = ReactClassInterface.hasOwnProperty(name) ?
     ReactClassInterface[name] :
     null;
@@ -431,7 +431,7 @@ function validateMethodOverride(proto, name) {
   }
 
   // Disallow defining methods more than once unless explicitly allowed.
-  if (proto.hasOwnProperty(name)) {
+  if (isAlreadyDefined) {
     invariant(
       specPolicy === SpecPolicy.DEFINE_MANY ||
       specPolicy === SpecPolicy.DEFINE_MANY_MERGED,
@@ -465,6 +465,7 @@ function mixSpecIntoComponent(Constructor, spec) {
   );
 
   var proto = Constructor.prototype;
+  var autoBindPairs = proto.__reactAutoBindPairs;
 
   // By handling mixins before any other properties, we ensure the same
   // chaining order is applied to methods with DEFINE_MANY policy, whether
@@ -484,7 +485,8 @@ function mixSpecIntoComponent(Constructor, spec) {
     }
 
     var property = spec[name];
-    validateMethodOverride(proto, name);
+    var isAlreadyDefined = proto.hasOwnProperty(name);
+    validateMethodOverride(isAlreadyDefined, name);
 
     if (RESERVED_SPEC_KEYS.hasOwnProperty(name)) {
       RESERVED_SPEC_KEYS[name](Constructor, property);
@@ -495,7 +497,6 @@ function mixSpecIntoComponent(Constructor, spec) {
       // 2. Overridden methods (that were mixed in).
       var isReactClassMethod =
         ReactClassInterface.hasOwnProperty(name);
-      var isAlreadyDefined = proto.hasOwnProperty(name);
       var isFunction = typeof property === 'function';
       var shouldAutoBind =
         isFunction &&
@@ -504,10 +505,7 @@ function mixSpecIntoComponent(Constructor, spec) {
         spec.autobind !== false;
 
       if (shouldAutoBind) {
-        if (!proto.__reactAutoBindMap) {
-          proto.__reactAutoBindMap = {};
-        }
-        proto.__reactAutoBindMap[name] = property;
+        autoBindPairs.push(name, property);
         proto[name] = property;
       } else {
         if (isAlreadyDefined) {
@@ -700,14 +698,14 @@ function bindAutoBindMethod(component, method) {
  * @param {object} component Component whose method is going to be bound.
  */
 function bindAutoBindMethods(component) {
-  for (var autoBindKey in component.__reactAutoBindMap) {
-    if (component.__reactAutoBindMap.hasOwnProperty(autoBindKey)) {
-      var method = component.__reactAutoBindMap[autoBindKey];
-      component[autoBindKey] = bindAutoBindMethod(
-        component,
-        method
-      );
-    }
+  var pairs = component.__reactAutoBindPairs;
+  for (var i = 0; i < pairs.length; i += 2) {
+    var autoBindKey = pairs[i];
+    var method = pairs[i + 1];
+    component[autoBindKey] = bindAutoBindMethod(
+      component,
+      method
+    );
   }
 }
 
@@ -812,7 +810,7 @@ var ReactClass = {
       }
 
       // Wire up auto-binding
-      if (this.__reactAutoBindMap) {
+      if (this.__reactAutoBindPairs.length) {
         bindAutoBindMethods(this);
       }
 
@@ -846,6 +844,7 @@ var ReactClass = {
     };
     Constructor.prototype = new ReactClassComponent();
     Constructor.prototype.constructor = Constructor;
+    Constructor.prototype.__reactAutoBindPairs = [];
 
     injectedMixins.forEach(
       mixSpecIntoComponent.bind(null, Constructor)