how to add conditional html component react code example

Example 1: conditional style react

class App extends Component {
  constructor() {
    super()
    this.state = { isRed: true }
  }

  render() {
    const isRed = this.state.isRed

    return <p style={{ color: isRed ? 'red' : 'blue' }}>Example Text</p>
  }
}

Example 2: conditional rendering react

function Mailbox(props) {
  const unreadMessages = props.unreadMessages;
  return (
    <div>
      <h1>Hello!</h1>
      {unreadMessages.length > 0 &&        <h2>          You have {unreadMessages.length} unread messages.        </h2>      }    </div>
  );
}

const messages = ['React', 'Re: React', 'Re:Re: React'];
ReactDOM.render(
  <Mailbox unreadMessages={messages} />,
  document.getElementById('root')
);