Release 1.2.1

https://github.com/react-navigation/react-navigation/issues/3279

flow/react-navigation.js

@@ -705,7 +705,7 @@ declare module 'react-navigation' {
       toString: () => string,
     },
     init: {
-      (payload: { params?: NavigationParams }): NavigationInitAction,
+      (payload?: { params?: NavigationParams }): NavigationInitAction,
       toString: () => string,
     },
     navigate: {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-navigation",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Routing and navigation for your React Native apps",
   "main": "src/react-navigation.js",
   "repository": {

src/navigators/__tests__/StackNavigator-test.js

@@ -1,15 +1,22 @@
 import React, { Component } from 'react';
-import { View } from 'react-native';
+import { StyleSheet, View } from 'react-native';
 import renderer from 'react-test-renderer';
 
 import StackNavigator from '../StackNavigator';
 
+const styles = StyleSheet.create({
+  header: {
+    opacity: 0.5,
+  },
+});
+
 class HomeScreen extends Component {
   static navigationOptions = ({ navigation }) => ({
     title: `Welcome ${
       navigation.state.params ? navigation.state.params.user : 'anonymous'
     }`,
     gesturesEnabled: true,
+    headerStyle: [{ backgroundColor: 'red' }, styles.header],
   });
 
   render() {

src/routers/StackRouter.js

@@ -392,21 +392,28 @@ export default (routeConfigs, stackConfig = {}) => {
           // undefined on either the state or the action
           return state;
         }
-        const resetAction = action;
+        const newStackActions = action.actions;
 
         return {
           ...state,
-          routes: resetAction.actions.map(childAction => {
-            const router = childRouters[childAction.routeName];
+          routes: newStackActions.map(newStackAction => {
+            const router = childRouters[newStackAction.routeName];
+
             let childState = {};
+
             if (router) {
+              const childAction =
+                newStackAction.action ||
+                NavigationActions.init({ params: newStackAction.params });
+
               childState = router.getStateForAction(childAction);
             }
+
             return {
-              params: childAction.params,
+              params: newStackAction.params,
               ...childState,
-              routeName: childAction.routeName,
-              key: childAction.key || generateKey(),
+              routeName: newStackAction.routeName,
+              key: newStackAction.key || generateKey(),
             };
           }),
           index: action.index,

src/views/Header/Header.js

@@ -441,10 +441,7 @@ class Header extends React.PureComponent {
 
     const { options } = this.props.getScreenDetails(scene);
     const { headerStyle = {} } = options;
-    const headerStyleObj =
-      typeof headerStyle === 'number'
-        ? StyleSheet.flatten(headerStyle)
-        : headerStyle;
+    const headerStyleObj = StyleSheet.flatten(headerStyle);
     const appBarHeight = getAppBarHeight(isLandscape);
 
     const {