title: TypeError: Cannot read property 'any' of undefined React
body: <p>I'm new to React and I'm trying to make small app by following a Udemy tutorial. The application contains a form. When I import <a href="https://github.com/erikras/redux-form" rel="nofollow noreferrer">redux-form</a> library into my project, I got the below console error.</p>
  
  <p><a href="https://i.stack.imgur.com/oMu9R.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/oMu9R.png" alt="enter image description here"></a> 
  <a href="https://i.stack.imgur.com/JfgN3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JfgN3.png" alt="enter image description here"></a></p>
  
  <p><strong>package.json</strong></p>
  
  <pre><code>"dependencies": {
      "axios": "^0.18.0",
      "babel-preset-stage-1": "^6.1.18",
      "lodash": "^3.10.1",
      "react": "16.3.2",
      "react-countdown-now": "^1.3.0",
      "react-dom": "16.3.2",
      "react-redux": "5.0.7",
      "react-router": "^3.2.0",
      "redux": "4.0.0",
      "redux-form": "^4.1.3",
      "redux-promise": "^0.5.3"
    }
  </code></pre>
  
  <p>post_new.js contains the form.</p>
  
  <pre><code>import React, { Component } from 'react';
  import { reduxForm } from 'redux-form';
  
  class PostsNew extends Component {
      render() {
          return (
              &lt;form onSubmit={handleSubmit}&gt;
                  &lt;h3&gt;Create a new post&lt;/h3&gt;
                  &lt;div className="form-group"&gt;
                      &lt;label&gt;Title&lt;/label&gt;
                      &lt;input type="text" className="form-control" /&gt;
                  &lt;/div&gt;
                  &lt;div className="form-group"&gt;
                      &lt;label&gt;Categories&lt;/label&gt;
                      &lt;input type="text" className="form-control"/&gt;
                  &lt;/div&gt; 
                  &lt;div className="form-group"&gt;
                      &lt;label&gt;Content&lt;/label&gt;
                      &lt;textarea className="form-control"/&gt;
                  &lt;/div&gt;
  
                  &lt;button type="submit" className="btn btn-primary"&gt;Submit&lt;/button&gt;
              &lt;/form&gt;    
          );
      }
  }
  export default reduxForm(
      {
          form: 'PostsNewForm',
          fields: ['title','categories','content']
      }
  )(PostsNew);
  </code></pre>
  
  <p>also imported <code>redux-form</code> in reducers _> index.js</p>
  
  <pre><code>import { combineReducers } from 'redux';
  import PostReducer from './reducer_posts';
  import { reducer as formReducer } from 'redux-form';
  
  const rootReducer = combineReducers({
    posts: PostReducer,
    form: formReducer
  });
  
  export default rootReducer;
  </code></pre>