title: TypeError: item.map is not a function
body: <p>I'm using react and redux and I'm trying a simple example.
  If I clicked the button, then the number should increment by 1. 
  But when I currently click the button you'll see the following error, <code>TypeError: item.map is not a function</code>. Is there a problem with my code?</p>
  
  <pre><code>class Menu extends Component {
    componentDidMount() {
      this.props.getItems();
    }
  
    plus = () =&gt;{
      this.props.getplus();
    }
  
    render() {
      const {item } = this.props.item
      return (
        &lt;div&gt;
          {item.map(items =&gt; {
            &lt;buttom onClick={this.plus}&gt; + &lt;/button&gt;  &lt;div&gt;{count}&lt;/div&gt;     
          }               
        &lt;/div&gt;
      )
     }
  
   const mapStateToProps = (state) =&gt; ({
     item: state.item
   })
  
  export default connect(mapStateToProps , { getItems, getplus }) (Menu);
  </code></pre>
  
  <p>itemAction.js</p>
  
  <pre><code>export const getItems = () =&gt;{
    return {
      type: GET_ITEMS
    }
  }
  
  export const getplus = () =&gt; {
    return {
      type: PLUS_ITEMS
    }
  }
  </code></pre>
  
  <p>Reducer.js</p>
  
  <pre><code>const initialState = {
    item: [
      {
        count:0
      },
    ],
  }
  
  export default function (state = initialState, action) {
    switch(action.type){
      case GET_ITEMS:
        return {
          ...state
        }
        default:
          return state;
     case PLUS_ITEMS:
       return {
         item: state.item.count++
       }
     }
   }
  </code></pre>