functional components react

import React from 'react'; const App = () => {  const greeting = 'Hello Function Component!';   return <Headline value={greeting} />;}; const Headline = ({ value }) =>  <h1>{value}</h1>; export default App;

function Comment(props) {
  return (
    <div className="Comment">
      <div className="UserInfo">
        <img className="Avatar"
          src={props.author.avatarUrl}
          alt={props.author.name}
        />
        <div className="UserInfo-name">
          {props.author.name}
        </div>
      </div>
      <div className="Comment-text">
        {props.text}
      </div>
      <div className="Comment-date">
        {formatDate(props.date)}
      </div>
    </div>
  );
}

const MySubComponent = (props) => {
    if (props.display) {
        return <p>This text is displayed</p>
    }
}

class MyComponent extends React.Component {
    render() {
        return (
            <MySubComponent display={true} />
        )
    }
}