title: Expected the reducer to be a function - React Native, Redux
body: <p>I learning react native and redux and I'm having a problem in my code that i can't solve. 
  when I running my code on iPhone simulator (iOS 10.3) I'm getting the error: "Expected the reducer to be a function".</p>
  
  <p>Here is all of my code (very short, very basic):</p>
  
  <p>src/app.js:</p>
  
  <pre><code>import React from 'react';
  import { View } from 'react-native';
  import { Provider } from 'react-redux';
  import { createStore } from 'redux';
  import reducers from './reducers';
  import {Header} from 'native-base';
  
  const App = () =&gt; {
    return(
      &lt;Provider store={createStore(reducers)}&gt;
        &lt;View&gt;
          &lt;Header /&gt;
        &lt;/View&gt;
      &lt;/Provider&gt;
    )
  }
  
  export default App;
  </code></pre>
  
  <p>src/reducers/index.js:</p>
  
  <pre><code>import { combineReducers } from 'redux';
  
  export default combineReducers({
      libraries: () =&gt; []
  });
  </code></pre>
  
  <p>index.ios.js:</p>
  
  <pre><code>import {AppRegistry} from 'react-native';
  import App from './src/app';
  
  AppRegistry.registerComponent('project', () =&gt;  App);
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/kOwKS.png" rel="nofollow noreferrer">the exact error message</a></p>
  
  <p>Thank you all, 
     Roei.</p>