React and Redux - Extract Local State into Redux

JavaScript
1

Tell us what’s happening:

I have completed the challenge but from why the submitNewMessage Function is using on submitMessage … please someon explain the use of this term here

Your code so far

// 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:
const Provider = ReactRedux.Provider;
const connect = ReactRedux.connect;

// Change code below this line
class Presentational extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      input: ''
    }
    this.handleChange = this.handleChange.bind(this);
    this.submitMessage = this.submitMessage.bind(this);
  }
  handleChange(event) {
    this.setState({
      input: event.target.value
    });
  }
  submitMessage() {
   this.props.submitNewMessage(this.state.input);
   this.setState({
      input : ''
   })
  }
  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.props.messages.map( (message, idx) => {
              return (
                 <li key={idx}>{message}</li>
              )
            })
          }
        </ul>
      </div>
    );
  }
};
// Change code above this line

const mapStateToProps = (state) => {
  return {messages: state}
};

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

const Container = connect(mapStateToProps, mapDispatchToProps)(Presentational);

class AppWrapper extends React.Component {
  render() {
    return (
      <Provider store={store}>
        <Container/>
      </Provider>
    );
  }
};

Your browser information:

User Agent is: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Challenge Information:

React and Redux - Extract Local State into Redux

1 Like
2

Not sure if I understand the question.

The reason why submitNewMessage is not used directly as the handler and is called inside submitMessage is so the click handler can reset the state of the controlled input as well. The submitMessage handler does two things, call the submitNewMessage handler that was passed as a prop and reset the Presentational component local state for the input element.

3

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