class DisplayMessages extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      input: '',
      messages: []
    }
    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  };

  handleChange(e) {
    this.setState({
      input: e.target.value
    })
  }

  handleSubmit(e) {
    e.preventDefault();
    this.setState({
      messages: this.state.messages.concat(this.state.input),
      input: ''
    });
  }

  render() {
    const listMessages = this.state.messages.map((message, index) =>
      <li key={index}>{message}</li>
    );
    return (
      <div>
        <h2>Type in a new Message:</h2>
        { /* render an input, button, and ul here */ }
        <input type="text" onChange={this.handleChange} value={this.state.input} />
        <button type="submit" onClick={this.handleSubmit} value="submit">Click</button>

        <ul>{listMessages}</ul>
      </div>
    );
  }
};