From dbfcea3a62ec26588f329695dd26b2d2df4632a8 Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Thu, 20 Jul 2017 00:33:12 +0100
Subject: [PATCH 1/6] Inline traverseAllChildren into ReactChildren

---
 src/isomorphic/children/ReactChildren.js      | 201 +++++++++++++++-
 .../children/traverseAllChildren.js           | 214 ------------------
 2 files changed, 200 insertions(+), 215 deletions(-)
 delete mode 100644 src/isomorphic/children/traverseAllChildren.js

diff --git a/src/isomorphic/children/ReactChildren.js b/src/isomorphic/children/ReactChildren.js
index 91787952cf3..044513d2d5b 100644
--- a/src/isomorphic/children/ReactChildren.js
+++ b/src/isomorphic/children/ReactChildren.js
@@ -15,16 +15,215 @@ var PooledClass = require('PooledClass');
 var ReactElement = require('ReactElement');
 
 var emptyFunction = require('fbjs/lib/emptyFunction');
-var traverseAllChildren = require('traverseAllChildren');
+var invariant = require('fbjs/lib/invariant');
 
 var twoArgumentPooler = PooledClass.twoArgumentPooler;
 var fourArgumentPooler = PooledClass.fourArgumentPooler;
 
+if (__DEV__) {
+  var warning = require('fbjs/lib/warning');
+  var {getStackAddendum} = require('ReactDebugCurrentFrame');
+}
+
+var ITERATOR_SYMBOL = typeof Symbol === 'function' && Symbol.iterator;
+var FAUX_ITERATOR_SYMBOL = '@@iterator'; // Before Symbol spec.
+// The Symbol used to tag the ReactElement type. If there is no native Symbol
+// nor polyfill, then a plain number is used for performance.
+var REACT_ELEMENT_TYPE =
+  (typeof Symbol === 'function' && Symbol.for && Symbol.for('react.element')) ||
+  0xeac7;
+
+var SEPARATOR = '.';
+var SUBSEPARATOR = ':';
+
+/**
+ * Escape and wrap key so it is safe to use as a reactid
+ *
+ * @param {string} key to be escaped.
+ * @return {string} the escaped key.
+ */
+function escape(key: string): string {
+  var escapeRegex = /[=:]/g;
+  var escaperLookup = {
+    '=': '=0',
+    ':': '=2',
+  };
+  var escapedString = ('' + key).replace(escapeRegex, function(match) {
+    return escaperLookup[match];
+  });
+
+  return '$' + escapedString;
+}
+
+/**
+ * TODO: Test that a single child and an array with one item have the same key
+ * pattern.
+ */
+
+var didWarnAboutMaps = false;
+
 var userProvidedKeyEscapeRegex = /\/+/g;
 function escapeUserProvidedKey(text) {
   return ('' + text).replace(userProvidedKeyEscapeRegex, '$&/');
 }
 
+/**
+ * @param {?*} children Children tree container.
+ * @param {!string} nameSoFar Name of the key path so far.
+ * @param {!function} callback Callback to invoke with each child found.
+ * @param {?*} traverseContext Used to pass information throughout the traversal
+ * process.
+ * @return {!number} The number of children in this subtree.
+ */
+function traverseAllChildrenImpl(
+  children,
+  nameSoFar,
+  callback,
+  traverseContext,
+) {
+  var type = typeof children;
+
+  if (type === 'undefined' || type === 'boolean') {
+    // All of the above are perceived as null.
+    children = null;
+  }
+
+  if (
+    children === null ||
+    type === 'string' ||
+    type === 'number' ||
+    // The following is inlined from ReactElement. This means we can optimize
+    // some checks. React Fiber also inlines this logic for similar purposes.
+    (type === 'object' && children.$$typeof === REACT_ELEMENT_TYPE)
+  ) {
+    callback(
+      traverseContext,
+      children,
+      // If it's the only child, treat the name as if it was wrapped in an array
+      // so that it's consistent if the number of children grows.
+      nameSoFar === '' ? SEPARATOR + getComponentKey(children, 0) : nameSoFar,
+    );
+    return 1;
+  }
+
+  var child;
+  var nextName;
+  var subtreeCount = 0; // Count of children found in the current subtree.
+  var nextNamePrefix = nameSoFar === '' ? SEPARATOR : nameSoFar + SUBSEPARATOR;
+
+  if (Array.isArray(children)) {
+    for (var i = 0; i < children.length; i++) {
+      child = children[i];
+      nextName = nextNamePrefix + getComponentKey(child, i);
+      subtreeCount += traverseAllChildrenImpl(
+        child,
+        nextName,
+        callback,
+        traverseContext,
+      );
+    }
+  } else {
+    var iteratorFn =
+      (ITERATOR_SYMBOL && children[ITERATOR_SYMBOL]) ||
+      children[FAUX_ITERATOR_SYMBOL];
+    if (typeof iteratorFn === 'function') {
+      if (__DEV__) {
+        // Warn about using Maps as children
+        if (iteratorFn === children.entries) {
+          warning(
+            didWarnAboutMaps,
+            'Using Maps as children is unsupported and will likely yield ' +
+              'unexpected results. Convert it to a sequence/iterable of keyed ' +
+              'ReactElements instead.%s',
+            getStackAddendum(),
+          );
+          didWarnAboutMaps = true;
+        }
+      }
+
+      var iterator = iteratorFn.call(children);
+      var step;
+      var ii = 0;
+      while (!(step = iterator.next()).done) {
+        child = step.value;
+        nextName = nextNamePrefix + getComponentKey(child, ii++);
+        subtreeCount += traverseAllChildrenImpl(
+          child,
+          nextName,
+          callback,
+          traverseContext,
+        );
+      }
+    } else if (type === 'object') {
+      var addendum = '';
+      if (__DEV__) {
+        addendum =
+          ' If you meant to render a collection of children, use an array ' +
+          'instead.' +
+          getStackAddendum();
+      }
+      var childrenString = '' + children;
+      invariant(
+        false,
+        'Objects are not valid as a React child (found: %s).%s',
+        childrenString === '[object Object]'
+          ? 'object with keys {' + Object.keys(children).join(', ') + '}'
+          : childrenString,
+        addendum,
+      );
+    }
+  }
+
+  return subtreeCount;
+}
+
+/**
+ * Traverses children that are typically specified as `props.children`, but
+ * might also be specified through attributes:
+ *
+ * - `traverseAllChildren(this.props.children, ...)`
+ * - `traverseAllChildren(this.props.leftPanelChildren, ...)`
+ *
+ * The `traverseContext` is an optional argument that is passed through the
+ * entire traversal. It can be used to store accumulations or anything else that
+ * the callback might find relevant.
+ *
+ * @param {?*} children Children tree object.
+ * @param {!function} callback To invoke upon traversing each child.
+ * @param {?*} traverseContext Context for traversal.
+ * @return {!number} The number of children in this subtree.
+ */
+function traverseAllChildren(children, callback, traverseContext) {
+  if (children == null) {
+    return 0;
+  }
+
+  return traverseAllChildrenImpl(children, '', callback, traverseContext);
+}
+
+/**
+ * Generate a key string that identifies a component within a set.
+ *
+ * @param {*} component A component that could contain a manual key.
+ * @param {number} index Index that is used if a manual key is not provided.
+ * @return {string}
+ */
+function getComponentKey(component, index) {
+  // Do some typechecking here since we call this blindly. We want to ensure
+  // that we don't block potential future ES APIs.
+  if (
+    typeof component === 'object' &&
+    component !== null &&
+    component.key != null
+  ) {
+    // Explicit key
+    return escape(component.key);
+  }
+  // Implicit key determined by the index in the set
+  return index.toString(36);
+}
+
+
 /**
  * PooledClass representing the bookkeeping associated with performing a child
  * traversal. Allows avoiding binding callbacks.
diff --git a/src/isomorphic/children/traverseAllChildren.js b/src/isomorphic/children/traverseAllChildren.js
deleted file mode 100644
index 9ae26509b22..00000000000
--- a/src/isomorphic/children/traverseAllChildren.js
+++ /dev/null
@@ -1,214 +0,0 @@
-/**
- * Copyright 2013-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- *
- * @providesModule traverseAllChildren
- */
-
-'use strict';
-
-var invariant = require('fbjs/lib/invariant');
-
-var ITERATOR_SYMBOL = typeof Symbol === 'function' && Symbol.iterator;
-var FAUX_ITERATOR_SYMBOL = '@@iterator'; // Before Symbol spec.
-// The Symbol used to tag the ReactElement type. If there is no native Symbol
-// nor polyfill, then a plain number is used for performance.
-var REACT_ELEMENT_TYPE =
-  (typeof Symbol === 'function' && Symbol.for && Symbol.for('react.element')) ||
-  0xeac7;
-
-if (__DEV__) {
-  var warning = require('fbjs/lib/warning');
-  var {getStackAddendum} = require('ReactDebugCurrentFrame');
-}
-
-var SEPARATOR = '.';
-var SUBSEPARATOR = ':';
-
-/**
- * Escape and wrap key so it is safe to use as a reactid
- *
- * @param {string} key to be escaped.
- * @return {string} the escaped key.
- */
-function escape(key: string): string {
-  var escapeRegex = /[=:]/g;
-  var escaperLookup = {
-    '=': '=0',
-    ':': '=2',
-  };
-  var escapedString = ('' + key).replace(escapeRegex, function(match) {
-    return escaperLookup[match];
-  });
-
-  return '$' + escapedString;
-}
-
-/**
- * TODO: Test that a single child and an array with one item have the same key
- * pattern.
- */
-
-var didWarnAboutMaps = false;
-
-/**
- * Generate a key string that identifies a component within a set.
- *
- * @param {*} component A component that could contain a manual key.
- * @param {number} index Index that is used if a manual key is not provided.
- * @return {string}
- */
-function getComponentKey(component, index) {
-  // Do some typechecking here since we call this blindly. We want to ensure
-  // that we don't block potential future ES APIs.
-  if (
-    typeof component === 'object' &&
-    component !== null &&
-    component.key != null
-  ) {
-    // Explicit key
-    return escape(component.key);
-  }
-  // Implicit key determined by the index in the set
-  return index.toString(36);
-}
-
-/**
- * @param {?*} children Children tree container.
- * @param {!string} nameSoFar Name of the key path so far.
- * @param {!function} callback Callback to invoke with each child found.
- * @param {?*} traverseContext Used to pass information throughout the traversal
- * process.
- * @return {!number} The number of children in this subtree.
- */
-function traverseAllChildrenImpl(
-  children,
-  nameSoFar,
-  callback,
-  traverseContext,
-) {
-  var type = typeof children;
-
-  if (type === 'undefined' || type === 'boolean') {
-    // All of the above are perceived as null.
-    children = null;
-  }
-
-  if (
-    children === null ||
-    type === 'string' ||
-    type === 'number' ||
-    // The following is inlined from ReactElement. This means we can optimize
-    // some checks. React Fiber also inlines this logic for similar purposes.
-    (type === 'object' && children.$$typeof === REACT_ELEMENT_TYPE)
-  ) {
-    callback(
-      traverseContext,
-      children,
-      // If it's the only child, treat the name as if it was wrapped in an array
-      // so that it's consistent if the number of children grows.
-      nameSoFar === '' ? SEPARATOR + getComponentKey(children, 0) : nameSoFar,
-    );
-    return 1;
-  }
-
-  var child;
-  var nextName;
-  var subtreeCount = 0; // Count of children found in the current subtree.
-  var nextNamePrefix = nameSoFar === '' ? SEPARATOR : nameSoFar + SUBSEPARATOR;
-
-  if (Array.isArray(children)) {
-    for (var i = 0; i < children.length; i++) {
-      child = children[i];
-      nextName = nextNamePrefix + getComponentKey(child, i);
-      subtreeCount += traverseAllChildrenImpl(
-        child,
-        nextName,
-        callback,
-        traverseContext,
-      );
-    }
-  } else {
-    var iteratorFn =
-      (ITERATOR_SYMBOL && children[ITERATOR_SYMBOL]) ||
-      children[FAUX_ITERATOR_SYMBOL];
-    if (typeof iteratorFn === 'function') {
-      if (__DEV__) {
-        // Warn about using Maps as children
-        if (iteratorFn === children.entries) {
-          warning(
-            didWarnAboutMaps,
-            'Using Maps as children is unsupported and will likely yield ' +
-              'unexpected results. Convert it to a sequence/iterable of keyed ' +
-              'ReactElements instead.%s',
-            getStackAddendum(),
-          );
-          didWarnAboutMaps = true;
-        }
-      }
-
-      var iterator = iteratorFn.call(children);
-      var step;
-      var ii = 0;
-      while (!(step = iterator.next()).done) {
-        child = step.value;
-        nextName = nextNamePrefix + getComponentKey(child, ii++);
-        subtreeCount += traverseAllChildrenImpl(
-          child,
-          nextName,
-          callback,
-          traverseContext,
-        );
-      }
-    } else if (type === 'object') {
-      var addendum = '';
-      if (__DEV__) {
-        addendum =
-          ' If you meant to render a collection of children, use an array ' +
-          'instead.' +
-          getStackAddendum();
-      }
-      var childrenString = '' + children;
-      invariant(
-        false,
-        'Objects are not valid as a React child (found: %s).%s',
-        childrenString === '[object Object]'
-          ? 'object with keys {' + Object.keys(children).join(', ') + '}'
-          : childrenString,
-        addendum,
-      );
-    }
-  }
-
-  return subtreeCount;
-}
-
-/**
- * Traverses children that are typically specified as `props.children`, but
- * might also be specified through attributes:
- *
- * - `traverseAllChildren(this.props.children, ...)`
- * - `traverseAllChildren(this.props.leftPanelChildren, ...)`
- *
- * The `traverseContext` is an optional argument that is passed through the
- * entire traversal. It can be used to store accumulations or anything else that
- * the callback might find relevant.
- *
- * @param {?*} children Children tree object.
- * @param {!function} callback To invoke upon traversing each child.
- * @param {?*} traverseContext Context for traversal.
- * @return {!number} The number of children in this subtree.
- */
-function traverseAllChildren(children, callback, traverseContext) {
-  if (children == null) {
-    return 0;
-  }
-
-  return traverseAllChildrenImpl(children, '', callback, traverseContext);
-}
-
-module.exports = traverseAllChildren;

From 8005895db4ce72ee708d545459bea09186a53c6c Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Thu, 20 Jul 2017 01:02:53 +0100
Subject: [PATCH 2/6] Remove ForEachBookKeeping

---
 src/isomorphic/children/ReactChildren.js | 29 ++++--------------------
 1 file changed, 5 insertions(+), 24 deletions(-)

diff --git a/src/isomorphic/children/ReactChildren.js b/src/isomorphic/children/ReactChildren.js
index 044513d2d5b..201f7c032df 100644
--- a/src/isomorphic/children/ReactChildren.js
+++ b/src/isomorphic/children/ReactChildren.js
@@ -223,27 +223,6 @@ function getComponentKey(component, index) {
   return index.toString(36);
 }
 
-
-/**
- * PooledClass representing the bookkeeping associated with performing a child
- * traversal. Allows avoiding binding callbacks.
- *
- * @constructor ForEachBookKeeping
- * @param {!function} forEachFunction Function to perform traversal with.
- * @param {?*} forEachContext Context to perform context with.
- */
-function ForEachBookKeeping(forEachFunction, forEachContext) {
-  this.func = forEachFunction;
-  this.context = forEachContext;
-  this.count = 0;
-}
-ForEachBookKeeping.prototype.destructor = function() {
-  this.func = null;
-  this.context = null;
-  this.count = 0;
-};
-PooledClass.addPoolingTo(ForEachBookKeeping, twoArgumentPooler);
-
 function forEachSingleChild(bookKeeping, child, name) {
   var {func, context} = bookKeeping;
   func.call(context, child, bookKeeping.count++);
@@ -265,12 +244,14 @@ function forEachChildren(children, forEachFunc, forEachContext) {
   if (children == null) {
     return children;
   }
-  var traverseContext = ForEachBookKeeping.getPooled(
+  var traverseContext = MapBookKeeping.getPooled(
+    null,
+    null,
     forEachFunc,
     forEachContext,
   );
   traverseAllChildren(children, forEachSingleChild, traverseContext);
-  ForEachBookKeeping.release(traverseContext);
+  MapBookKeeping.release(traverseContext);
 }
 
 /**
@@ -363,7 +344,7 @@ function mapChildren(children, func, context) {
   return result;
 }
 
-function forEachSingleChildDummy(traverseContext, child, name) {
+function forEachSingleChildDummy() {
   return null;
 }
 

From cd36b0aa5ea12fbe3d768deff315175c99e77a11 Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Thu, 20 Jul 2017 01:27:50 +0100
Subject: [PATCH 3/6] Inline traversal pooling logic into ReactChildren

---
 scripts/rollup/packaging.js                   |  2 +-
 scripts/rollup/results.json                   | 24 +++----
 src/isomorphic/children/ReactChildren.js      | 71 +++++++++++--------
 .../shared/utils/PooledClass.js               |  0
 4 files changed, 53 insertions(+), 44 deletions(-)
 rename src/{ => renderers}/shared/utils/PooledClass.js (100%)

diff --git a/scripts/rollup/packaging.js b/scripts/rollup/packaging.js
index 7ec7b2e8a8c..4e9fe72d169 100644
--- a/scripts/rollup/packaging.js
+++ b/scripts/rollup/packaging.js
@@ -24,7 +24,7 @@ const facebookWWWSrcDependencies = [
 
 // these files need to be copied to the react-native build
 const reactNativeSrcDependencies = [
-  'src/shared/utils/PooledClass.js',
+  'src/renderers/shared/utils/PooledClass.js',
   'src/renderers/shared/fiber/isomorphic/ReactTypes.js',
   'src/renderers/native/ReactNativeTypes.js',
 ];
diff --git a/scripts/rollup/results.json b/scripts/rollup/results.json
index 5a081e22d97..241be63bb88 100644
--- a/scripts/rollup/results.json
+++ b/scripts/rollup/results.json
@@ -1,28 +1,28 @@
 {
   "bundleSizes": {
     "react.development.js (UMD_DEV)": {
-      "size": 69376,
-      "gzip": 17780
+      "size": 65151,
+      "gzip": 16692
     },
     "react.production.min.js (UMD_PROD)": {
-      "size": 7585,
-      "gzip": 3002
+      "size": 6489,
+      "gzip": 2704
     },
     "react.development.js (NODE_DEV)": {
-      "size": 59667,
-      "gzip": 15411
+      "size": 55446,
+      "gzip": 14337
     },
     "react.production.min.js (NODE_PROD)": {
-      "size": 6451,
-      "gzip": 2576
+      "size": 5352,
+      "gzip": 2269
     },
     "React-dev.js (FB_DEV)": {
-      "size": 56905,
-      "gzip": 14622
+      "size": 52704,
+      "gzip": 13552
     },
     "React-prod.js (FB_PROD)": {
-      "size": 27099,
-      "gzip": 7215
+      "size": 24229,
+      "gzip": 6612
     },
     "react-dom.development.js (UMD_DEV)": {
       "size": 624799,
diff --git a/src/isomorphic/children/ReactChildren.js b/src/isomorphic/children/ReactChildren.js
index 201f7c032df..69ec5a5a7a3 100644
--- a/src/isomorphic/children/ReactChildren.js
+++ b/src/isomorphic/children/ReactChildren.js
@@ -11,15 +11,11 @@
 
 'use strict';
 
-var PooledClass = require('PooledClass');
 var ReactElement = require('ReactElement');
 
 var emptyFunction = require('fbjs/lib/emptyFunction');
 var invariant = require('fbjs/lib/invariant');
 
-var twoArgumentPooler = PooledClass.twoArgumentPooler;
-var fourArgumentPooler = PooledClass.fourArgumentPooler;
-
 if (__DEV__) {
   var warning = require('fbjs/lib/warning');
   var {getStackAddendum} = require('ReactDebugCurrentFrame');
@@ -244,40 +240,53 @@ function forEachChildren(children, forEachFunc, forEachContext) {
   if (children == null) {
     return children;
   }
-  var traverseContext = MapBookKeeping.getPooled(
+  var traverseContext = getPooledTraverseContext(
     null,
     null,
     forEachFunc,
     forEachContext,
   );
   traverseAllChildren(children, forEachSingleChild, traverseContext);
-  MapBookKeeping.release(traverseContext);
+  releaseTraverseContext(traverseContext);
 }
 
-/**
- * PooledClass representing the bookkeeping associated with performing a child
- * mapping. Allows avoiding binding callbacks.
- *
- * @constructor MapBookKeeping
- * @param {!*} mapResult Object containing the ordered map of results.
- * @param {!function} mapFunction Function to perform mapping with.
- * @param {?*} mapContext Context to perform mapping with.
- */
-function MapBookKeeping(mapResult, keyPrefix, mapFunction, mapContext) {
-  this.result = mapResult;
-  this.keyPrefix = keyPrefix;
-  this.func = mapFunction;
-  this.context = mapContext;
-  this.count = 0;
+var POOL_SIZE = 10;
+var traverseContextPool = [];
+function getPooledTraverseContext(
+  mapResult,
+  keyPrefix,
+  mapFunction,
+  mapContext,
+) {
+  if (traverseContextPool.length) {
+    var traverseContext = traverseContextPool.pop();
+    traverseContext.result = mapResult;
+    traverseContext.keyPrefix = keyPrefix;
+    traverseContext.func = mapFunction;
+    traverseContext.context = mapContext;
+    traverseContext.count = 0;
+    return traverseContext;
+  } else {
+    return {
+      result: mapResult,
+      keyPrefix: keyPrefix,
+      func: mapFunction,
+      context: mapContext,
+      count: 0,
+    };
+  }
+}
+
+function releaseTraverseContext(traverseContext) {
+  traverseContext.result = null;
+  traverseContext.keyPrefix = null;
+  traverseContext.func = null;
+  traverseContext.context = null;
+  traverseContext.count = 0;
+  if (traverseContextPool.length < POOL_SIZE) {
+    traverseContextPool.push(traverseContext);
+  }
 }
-MapBookKeeping.prototype.destructor = function() {
-  this.result = null;
-  this.keyPrefix = null;
-  this.func = null;
-  this.context = null;
-  this.count = 0;
-};
-PooledClass.addPoolingTo(MapBookKeeping, fourArgumentPooler);
 
 function mapSingleChildIntoContext(bookKeeping, child, childKey) {
   var {result, keyPrefix, func, context} = bookKeeping;
@@ -312,14 +321,14 @@ function mapIntoWithKeyPrefixInternal(children, array, prefix, func, context) {
   if (prefix != null) {
     escapedPrefix = escapeUserProvidedKey(prefix) + '/';
   }
-  var traverseContext = MapBookKeeping.getPooled(
+  var traverseContext = getPooledTraverseContext(
     array,
     escapedPrefix,
     func,
     context,
   );
   traverseAllChildren(children, mapSingleChildIntoContext, traverseContext);
-  MapBookKeeping.release(traverseContext);
+  releaseTraverseContext(traverseContext);
 }
 
 /**
diff --git a/src/shared/utils/PooledClass.js b/src/renderers/shared/utils/PooledClass.js
similarity index 100%
rename from src/shared/utils/PooledClass.js
rename to src/renderers/shared/utils/PooledClass.js

From c88787d6199c936796bf8c1c812eff71a03bb64f Mon Sep 17 00:00:00 2001
From: Dan Abramov <gaearon@fb.com>
Date: Thu, 20 Jul 2017 15:44:53 +0100
Subject: [PATCH 4/6] Reuse emptyFunction for dummy callback

---
 src/isomorphic/children/ReactChildren.js | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/isomorphic/children/ReactChildren.js b/src/isomorphic/children/ReactChildren.js
index 69ec5a5a7a3..5be236cc235 100644
--- a/src/isomorphic/children/ReactChildren.js
+++ b/src/isomorphic/children/ReactChildren.js
@@ -353,10 +353,6 @@ function mapChildren(children, func, context) {
   return result;
 }
 
-function forEachSingleChildDummy() {
-  return null;
-}
-
 /**
  * Count the number of children that are typically specified as
  * `props.children`.
@@ -367,7 +363,7 @@ function forEachSingleChildDummy() {
  * @return {number} The number of children.
  */
 function countChildren(children, context) {
-  return traverseAllChildren(children, forEachSingleChildDummy, null);
+  return traverseAllChildren(children, emptyFunction.thatReturnsNull, null);
 }
 
 /**

From ab9a5733874709de6d17647adab3360c83a69b5a Mon Sep 17 00:00:00 2001
From: Dan Abramov <gaearon@fb.com>
Date: Thu, 20 Jul 2017 15:52:11 +0100
Subject: [PATCH 5/6] Move code around

---
 src/isomorphic/children/ReactChildren.js | 76 ++++++++++++------------
 1 file changed, 38 insertions(+), 38 deletions(-)

diff --git a/src/isomorphic/children/ReactChildren.js b/src/isomorphic/children/ReactChildren.js
index 5be236cc235..dd70a5d9684 100644
--- a/src/isomorphic/children/ReactChildren.js
+++ b/src/isomorphic/children/ReactChildren.js
@@ -63,6 +63,44 @@ function escapeUserProvidedKey(text) {
   return ('' + text).replace(userProvidedKeyEscapeRegex, '$&/');
 }
 
+var POOL_SIZE = 10;
+var traverseContextPool = [];
+function getPooledTraverseContext(
+  mapResult,
+  keyPrefix,
+  mapFunction,
+  mapContext,
+) {
+  if (traverseContextPool.length) {
+    var traverseContext = traverseContextPool.pop();
+    traverseContext.result = mapResult;
+    traverseContext.keyPrefix = keyPrefix;
+    traverseContext.func = mapFunction;
+    traverseContext.context = mapContext;
+    traverseContext.count = 0;
+    return traverseContext;
+  } else {
+    return {
+      result: mapResult,
+      keyPrefix: keyPrefix,
+      func: mapFunction,
+      context: mapContext,
+      count: 0,
+    };
+  }
+}
+
+function releaseTraverseContext(traverseContext) {
+  traverseContext.result = null;
+  traverseContext.keyPrefix = null;
+  traverseContext.func = null;
+  traverseContext.context = null;
+  traverseContext.count = 0;
+  if (traverseContextPool.length < POOL_SIZE) {
+    traverseContextPool.push(traverseContext);
+  }
+}
+
 /**
  * @param {?*} children Children tree container.
  * @param {!string} nameSoFar Name of the key path so far.
@@ -250,44 +288,6 @@ function forEachChildren(children, forEachFunc, forEachContext) {
   releaseTraverseContext(traverseContext);
 }
 
-var POOL_SIZE = 10;
-var traverseContextPool = [];
-function getPooledTraverseContext(
-  mapResult,
-  keyPrefix,
-  mapFunction,
-  mapContext,
-) {
-  if (traverseContextPool.length) {
-    var traverseContext = traverseContextPool.pop();
-    traverseContext.result = mapResult;
-    traverseContext.keyPrefix = keyPrefix;
-    traverseContext.func = mapFunction;
-    traverseContext.context = mapContext;
-    traverseContext.count = 0;
-    return traverseContext;
-  } else {
-    return {
-      result: mapResult,
-      keyPrefix: keyPrefix,
-      func: mapFunction,
-      context: mapContext,
-      count: 0,
-    };
-  }
-}
-
-function releaseTraverseContext(traverseContext) {
-  traverseContext.result = null;
-  traverseContext.keyPrefix = null;
-  traverseContext.func = null;
-  traverseContext.context = null;
-  traverseContext.count = 0;
-  if (traverseContextPool.length < POOL_SIZE) {
-    traverseContextPool.push(traverseContext);
-  }
-}
-
 function mapSingleChildIntoContext(bookKeeping, child, childKey) {
   var {result, keyPrefix, func, context} = bookKeeping;
 

From 5d8cd2ac4d7b98ffb0b587d6f2d03cd95a20a559 Mon Sep 17 00:00:00 2001
From: Dan Abramov <gaearon@fb.com>
Date: Thu, 20 Jul 2017 15:54:17 +0100
Subject: [PATCH 6/6] Record sizes

---
 scripts/rollup/results.json | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/scripts/rollup/results.json b/scripts/rollup/results.json
index 241be63bb88..a55a0d0f6c4 100644
--- a/scripts/rollup/results.json
+++ b/scripts/rollup/results.json
@@ -1,28 +1,28 @@
 {
   "bundleSizes": {
     "react.development.js (UMD_DEV)": {
-      "size": 65151,
-      "gzip": 16692
+      "size": 65104,
+      "gzip": 16679
     },
     "react.production.min.js (UMD_PROD)": {
-      "size": 6489,
-      "gzip": 2704
+      "size": 6478,
+      "gzip": 2700
     },
     "react.development.js (NODE_DEV)": {
-      "size": 55446,
-      "gzip": 14337
+      "size": 55397,
+      "gzip": 14325
     },
     "react.production.min.js (NODE_PROD)": {
-      "size": 5352,
-      "gzip": 2269
+      "size": 5343,
+      "gzip": 2268
     },
     "React-dev.js (FB_DEV)": {
-      "size": 52704,
-      "gzip": 13552
+      "size": 52655,
+      "gzip": 13543
     },
     "React-prod.js (FB_PROD)": {
-      "size": 24229,
-      "gzip": 6612
+      "size": 24178,
+      "gzip": 6601
     },
     "react-dom.development.js (UMD_DEV)": {
       "size": 624799,