---
id: 5a24c314108439a4d4036148
title: Connect Redux to the Messages App
challengeType: 6
isRequired: false
---

## Description
<section id='description'>
Now that you understand how to use <code>connect</code> to connect React to Redux, you can apply what you've learned to your React component that handles messages.
In the last lesson, the component you connected to Redux was named <code>Presentational</code>, and this wasn't arbitrary. This term <i>generally</i> refers to React components that are not directly connected to Redux. They are simply responsible for the presentation of UI and do this as a function of the props they receive. By contrast, container components are connected to Redux. These are typically responsible for dispatching actions to the store and often pass store state to child components as props.
</section>

## Instructions
<section id='instructions'>
The code editor has all the code you've written in this section so far. The only change is that the React component is renamed to <code>Presentational</code>. Create a new component held in a constant called <code>Container</code> that uses <code>connect</code> to connect the <code>Presentational</code> component to Redux. Then, in the <code>AppWrapper</code>, render the React Redux <code>Provider</code> component. Pass <code>Provider</code> the Redux <code>store</code> as a prop and render <code>Container</code> as a child. Once everything is setup, you will see the messages app rendered to the page again.
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: The <code>AppWrapper</code> should render to the page.
    testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return mockedComponent.find('AppWrapper').length === 1; })(), 'The <code>AppWrapper</code> should render to the page.');
  - text: The <code>Presentational</code> component should render an <code>h2</code>, <code>input</code>, <code>button</code>, and <code>ul</code> elements.
    testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return mockedComponent.find('Presentational').length === 1; })(), 'The <code>Presentational</code> component should render an <code>h2</code>, <code>input</code>, <code>button</code>, and <code>ul</code> elements.');
  - text: The <code>Presentational</code> component should render an <code>h2</code>, <code>input</code>, <code>button</code>, and <code>ul</code> elements.
    testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); const PresentationalComponent = mockedComponent.find('Presentational'); return ( PresentationalComponent.find('div').length === 1 && PresentationalComponent.find('h2').length === 1 && PresentationalComponent.find('button').length === 1 && PresentationalComponent.find('ul').length === 1 ); })(), 'The <code>Presentational</code> component should render an <code>h2</code>, <code>input</code>, <code>button</code>, and <code>ul</code> elements.');
  - text: The <code>Presentational</code> component should receive <code>messages</code> from the Redux store as a prop.
    testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); const PresentationalComponent = mockedComponent.find('Presentational'); const props = PresentationalComponent.props(); return Array.isArray(props.messages); })(), 'The <code>Presentational</code> component should receive <code>messages</code> from the Redux store as a prop.');
  - text: The <code>Presentational</code> component should receive the <code>submitMessage</code> action creator as a prop.
    testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); const PresentationalComponent = mockedComponent.find('Presentational'); const props = PresentationalComponent.props(); return typeof props.submitNewMessage === 'function'; })(), 'The <code>Presentational</code> component should receive the <code>submitMessage</code> action creator as a prop.');

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='jsx-seed'>

```jsx
// Redux:
const ADD = 'ADD';

const addMessage = (message) => {
  return {
    type: ADD,
    message: message
  }
};

const messageReducer = (state = [], action) => {
  switch (action.type) {
    case ADD:
      return [
        ...state,
        action.message
      ];
    default:
      return state;
  }
};

const store = Redux.createStore(messageReducer);

// React:
class Presentational extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      input: '',
      messages: []
    }
    this.handleChange = this.handleChange.bind(this);
    this.submitMessage = this.submitMessage.bind(this);
  }
  handleChange(event) {
    this.setState({
      input: event.target.value
    });
  }
  submitMessage() {
    const currentMessage = this.state.input;
    this.setState({
      input: '',
      messages: this.state.messages.concat(currentMessage)
    });
  }
  render() {
    return (
      <div>
        <h2>Type in a new Message:</h2>
        <input
          value={this.state.input}
          onChange={this.handleChange}/><br/>
        <button onClick={this.submitMessage}>Submit</button>
        <ul>
          {this.state.messages.map( (message, idx) => {
              return (
                 <li key={idx}>{message}</li>
              )
            })
          }
        </ul>
      </div>
    );
  }
};

// React-Redux:
const mapStateToProps = (state) => {
  return { messages: state }
};

const mapDispatchToProps = (dispatch) => {
  return {
    submitNewMessage: (newMessage) => {
       dispatch(addMessage(newMessage))
    }
  }
};

const Provider = ReactRedux.Provider;
const connect = ReactRedux.connect;

// define the Container component here:


class AppWrapper extends React.Component {
  constructor(props) {
    super(props);
  }
  render() {
    // complete the return statement:
    return (null);
  }
};
```

</div>


### After Test
<div id='jsx-teardown'>

```js
ReactDOM.render(<AppWrapper />, document.getElementById('root'))
```

</div>

</section>

## Solution
<section id='solution'>


```js
// Redux:
const ADD = 'ADD';

const addMessage = (message) => {
  return {
    type: ADD,
    message: message
  }
};

const messageReducer = (state = [], action) => {
  switch (action.type) {
    case ADD:
      return [
        ...state,
        action.message
      ];
    default:
      return state;
  }
};

const store = Redux.createStore(messageReducer);

// React:
class Presentational extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      input: '',
      messages: []
    }
 this.handleChange = this.handleChange.bind(this);
 this.submitMessage = this.submitMessage.bind(this);
  }
  handleChange(event) {
    this.setState({
      input: event.target.value
    });
  }
  submitMessage() {
    const currentMessage = this.state.input;
    this.setState({
      input: '',
      messages: this.state.messages.concat(currentMessage)
    });
  }
  render() {
    return (
      <div>
        <h2>Type in a new Message:</h2>
        <input
          value={this.state.input}
          onChange={this.handleChange}/><br/>
        <button onClick={this.submitMessage}>Submit</button>
        <ul>
          {this.state.messages.map( (message, idx) => {
              return (
                 <li key={idx}>{message}</li>
              )
            })
          }
        </ul>
      </div>
    );
  }
};

// React-Redux:
const mapStateToProps = (state) => {
  return { messages: state }
};

const mapDispatchToProps = (dispatch) => {
  return {
    submitNewMessage: (newMessage) => {
       dispatch(addMessage(newMessage))
    }
  }
};

const Provider = ReactRedux.Provider;
const connect = ReactRedux.connect;

// define the Container component here:
const Container = connect(mapStateToProps, mapDispatchToProps)(Presentational);

class AppWrapper extends React.Component {
  constructor(props) {
    super(props);
  }
  render() {
    // complete the return statement:
    return (
      <Provider store={store}>
        <Container/>
      </Provider>
    );
  }
};
```

</section>