UIManagerStatTracker

Reviewed By: @astreet

Differential Revision: D2442406

Libraries/ReactNative/ReactNativeBaseComponent.js

@@ -35,6 +35,8 @@ type ReactNativeBaseComponentViewConfig = {
   uiViewClassName: string;
 }
 
+// require('UIManagerStatTracker').install(); // uncomment to enable
+
 /**
  * @constructor ReactNativeBaseComponent
  * @extends ReactComponent

Libraries/ReactNative/UIManagerStatTracker.js

@@ -0,0 +1,57 @@
+/**
+ * Copyright (c) 2015-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 UIManagerStatTracker
+ * @flow
+ */
+'use strict';
+
+var RCTUIManager = require('NativeModules').UIManager;
+
+var installed = false;
+var UIManagerStatTracker = {
+  install: function() {
+    if (installed) {
+      return;
+    }
+    installed = true;
+    var statLogHandle;
+    var stats = {};
+    function printStats() {
+      console.log({UIManagerStatTracker: stats});
+      statLogHandle = null;
+    }
+    function incStat(key: string, increment: number) {
+      stats[key] = (stats[key] || 0) + increment;
+      if (!statLogHandle) {
+        statLogHandle = setImmediate(printStats);
+      }
+    }
+    var createViewOrig = RCTUIManager.createView;
+    RCTUIManager.createView = function(tag, className, rootTag, props) {
+      incStat('createView', 1);
+      incStat('setProp', Object.keys(props || []).length);
+      createViewOrig(tag, className, rootTag, props);
+    };
+    var updateViewOrig = RCTUIManager.updateView;
+    RCTUIManager.updateView = function(tag, className, props) {
+      incStat('updateView', 1);
+      incStat('setProp', Object.keys(props || []).length);
+      updateViewOrig(tag, className, props);
+    };
+    var manageChildrenOrig = RCTUIManager.manageChildren;
+    RCTUIManager.manageChildren = function(tag, moveFrom, moveTo, addTags, addIndices, remove) {
+      incStat('manageChildren', 1);
+      incStat('move', Object.keys(moveFrom || []).length);
+      incStat('remove', Object.keys(remove || []).length);
+      manageChildrenOrig(tag, moveFrom, moveTo, addTags, addIndices, remove);
+    };
+  },
+};
+
+module.exports = UIManagerStatTracker;