React: Use Advanced JavaScript in React Render Method

const inputStyle = {
  width: 235,
  margin: 5
}

class MagicEightBall extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      userInput: '',
      randomIndex: ''
    }
    this.ask = this.ask.bind(this);
    this.handleChange = this.handleChange.bind(this);
  }
  ask() {
    if (this.state.userInput) {
      this.setState({
        randomIndex: Math.floor(Math.random() * 20),
        userInput: ''
      });
    }
  }
  handleChange(event) {
    this.setState({
      userInput: event.target.value
    });
  }
  render() {
    const possibleAnswers = [
      'It is certain',
      'It is decidedly so',
      'Without a doubt', 
      'Yes, definitely',
      'You may rely on it',
      'As I see it, yes',
      'Outlook good',
      'Yes',
      'Signs point to yes',
      'Reply hazy try again',
      'Ask again later',
      'Better not tell you now',
      'Cannot predict now',
      'Concentrate and ask again',
      'Don\'t count on it', 
      'My reply is no',
      'My sources say no',
      'Most likely',
      'Outlook not so good',
      'Very doubtful'
    ];
    const answer = possibleAnswers[this.state.randomIndex] // << change code here
    return (
      <div>
        <input
          type="text"
          value={this.state.userInput}
          onChange={this.handleChange}
          style={inputStyle} /><br />
        <button onClick={this.ask}>
          Ask the Magic Eight Ball!
        </button><br />
        <h3>Answer:</h3>
        <p>
          { /* change code below this line */ }
          { answer }
          { /* change code above this line */ }
        </p>
      </div>
    );
  }
};