diff --git a/Examples/2048/Game2048.js b/Examples/2048/Game2048.js
index a6e041ceb..9fd6052c9 100644
--- a/Examples/2048/Game2048.js
+++ b/Examples/2048/Game2048.js
@@ -150,7 +150,7 @@ class Game2048 extends React.Component {
   startX: number;
   startY: number;
 
-  constructor(props) {
+  constructor(props: {}) {
     super(props);
     this.state = {
       board: new GameBoard(),
diff --git a/Examples/UIExplorer/ExampleTypes.js b/Examples/UIExplorer/ExampleTypes.js
new file mode 100644
index 000000000..7f6ff08d8
--- /dev/null
+++ b/Examples/UIExplorer/ExampleTypes.js
@@ -0,0 +1,30 @@
+/**
+ * The examples provided by Facebook are for non-commercial testing and
+ * evaluation purposes only.
+ *
+ * Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * @providesModule ExampleTypes
+ * @flow
+ */
+
+export type Example = {
+  title: string,
+  render: () => ?ReactElement<any, any, any>,
+  description?: string,
+};
+
+export type ExampleModule = {
+  title: string;
+  description: string;
+  examples: Array<Example>;
+  external?: bool;
+};
+
diff --git a/Examples/UIExplorer/MapViewExample.js b/Examples/UIExplorer/MapViewExample.js
index ab6bd0717..e8dae25ac 100644
--- a/Examples/UIExplorer/MapViewExample.js
+++ b/Examples/UIExplorer/MapViewExample.js
@@ -168,7 +168,7 @@ var MapViewExample = React.createClass({
         />
         <MapRegionInput
           onChange={this._onRegionInputChanged}
-          region={this.state.mapRegionInput}
+          region={this.state.mapRegionInput || undefined}
         />
       </View>
     );
diff --git a/Examples/UIExplorer/PointerEventsExample.js b/Examples/UIExplorer/PointerEventsExample.js
index 035f75814..cd402c471 100644
--- a/Examples/UIExplorer/PointerEventsExample.js
+++ b/Examples/UIExplorer/PointerEventsExample.js
@@ -181,7 +181,13 @@ var BoxOnlyExample = React.createClass({
   }
 });
 
-var exampleClasses = [
+type ExampleClass = {
+  Component: ReactClass<any, any, any>,
+  title: string,
+  description: string,
+};
+
+var exampleClasses: Array<ExampleClass> = [
   {
     Component: NoneExample,
     title: '`none`',
diff --git a/Examples/UIExplorer/UIExplorerList.js b/Examples/UIExplorer/UIExplorerList.js
index dd2336df5..948ac6f08 100644
--- a/Examples/UIExplorer/UIExplorerList.js
+++ b/Examples/UIExplorer/UIExplorerList.js
@@ -30,6 +30,8 @@ var {
 var { TestModule } = React.addons;
 var Settings = require('Settings');
 
+import type { Example, ExampleModule } from 'ExampleTypes';
+
 var createExamplePage = require('./createExamplePage');
 
 var COMPONENTS = [
@@ -107,9 +109,17 @@ COMPONENTS.concat(APIS).forEach((Example) => {
   }
 });
 
-class UIExplorerList extends React.Component {
+type Props = {
+  navigator: Array<{title: string, component: ReactClass<any,any,any>}>,
+  onExternalExampleRequested: Function,
+};
 
-  constructor(props) {
+
+
+class UIExplorerList extends React.Component {
+  props: Props;
+
+  constructor(props: Props) {
     super(props);
     this.state = {
       dataSource: ds.cloneWithRowsAndSections({
@@ -149,7 +159,7 @@ class UIExplorerList extends React.Component {
     );
   }
 
-  _renderSectionHeader(data, section) {
+  _renderSectionHeader(data: any, section: string) {
     return (
       <View style={styles.sectionHeader}>
         <Text style={styles.sectionHeaderTitle}>
@@ -159,7 +169,7 @@ class UIExplorerList extends React.Component {
     );
   }
 
-  _renderRow(example, i) {
+  _renderRow(example: ExampleModule, i: number) {
     return (
       <View key={i}>
         <TouchableHighlight onPress={() => this._onPressRow(example)}>
@@ -177,7 +187,7 @@ class UIExplorerList extends React.Component {
     );
   }
 
-  _search(text) {
+  _search(text: mixed) {
     var regex = new RegExp(text, 'i');
     var filter = (component) => regex.test(component.title);
 
@@ -191,7 +201,7 @@ class UIExplorerList extends React.Component {
     Settings.set({searchText: text});
   }
 
-  _onPressRow(example) {
+  _onPressRow(example: ExampleModule) {
     if (example.external) {
       this.props.onExternalExampleRequested(example);
       return;
diff --git a/Examples/UIExplorer/createExamplePage.js b/Examples/UIExplorer/createExamplePage.js
index c65ea7bf3..3d5a1ac88 100644
--- a/Examples/UIExplorer/createExamplePage.js
+++ b/Examples/UIExplorer/createExamplePage.js
@@ -23,16 +23,7 @@ var UIExplorerPage = require('./UIExplorerPage');
 
 var invariant = require('invariant');
 
-class Example extends React.Component {
-  title: string;
-  description: string;
-}
-
-type ExampleModule = {
-  title: string;
-  description: string;
-  examples: Array<Example>;
-};
+import type { Example, ExampleModule } from 'ExampleTypes';
 
 var createExamplePage = function(title: ?string, exampleModule: ExampleModule)
   : ReactClass<any, any, any> {
@@ -44,7 +35,7 @@ var createExamplePage = function(title: ?string, exampleModule: ExampleModule)
       description: exampleModule.description,
     },
 
-    getBlock: function(example, i) {
+    getBlock: function(example: Example, i) {
       // Hack warning: This is a hack because the www UI explorer requires
       // renderComponent to be called.
       var originalRender = React.render;
diff --git a/Libraries/CameraRoll/CameraRoll.js b/Libraries/CameraRoll/CameraRoll.js
index 6acc949e5..0d008ae75 100644
--- a/Libraries/CameraRoll/CameraRoll.js
+++ b/Libraries/CameraRoll/CameraRoll.js
@@ -92,6 +92,8 @@ var getPhotosReturnChecker = createStrictShapeTypeChecker({
 });
 
 class CameraRoll {
+
+  static GroupTypesOptions: Array<string>;
   /**
    * Saves the image with tag `tag` to the camera roll.
    *
diff --git a/Libraries/Utilities/PixelRatio.js b/Libraries/Utilities/PixelRatio.js
index e6c96b7fa..a3e4d9e77 100644
--- a/Libraries/Utilities/PixelRatio.js
+++ b/Libraries/Utilities/PixelRatio.js
@@ -67,9 +67,9 @@ class PixelRatio {
   static getPixelSizeForLayoutSize(layoutSize: number): number {
     return Math.round(layoutSize * PixelRatio.get());
   }
+
+  // No-op for iOS, but used on the web. Should not be documented.
+  static startDetecting() {}
 }
 
-// No-op for iOS, but used on the web. Should not be documented.
-PixelRatio.startDetecting = function() {};
-
 module.exports = PixelRatio;