1class MyComponent extends React.Component{
2    constructor(props){
3        super(props);
4    };
5    render(){
6        return(
7            <div>
8              <h1>
9              	My First React Component!
10              </h1>
11            </div>
12        );
13    }
14};
15

1function app() {
2    return (
3        <div>   
4            <h1>Hello World</h1>;
5        </div>
6    );
7}

1import React from 'react'; const App = () => {  const greeting = 'Hello Function Component!';   return <Headline value={greeting} />;}; const Headline = ({ value }) =>  <h1>{value}</h1>; export default App;

1function Comment(props) {
2  return (
3    <div className="Comment">
4      <div className="UserInfo">
5        <img className="Avatar"
6          src={props.author.avatarUrl}
7          alt={props.author.name}
8        />
9        <div className="UserInfo-name">
10          {props.author.name}
11        </div>
12      </div>
13      <div className="Comment-text">
14        {props.text}
15      </div>
16      <div className="Comment-date">
17        {formatDate(props.date)}
18      </div>
19    </div>
20  );
21}

1function Welcome(props) {  return <h1>Hello, {props.name}</h1>;
2}
3
4const element = <Welcome name="Sara" />;ReactDOM.render(
5  element,
6  document.getElementById('root')
7);

1const MySubComponent = (props) => {
2    if (props.display) {
3        return <p>This text is displayed</p>
4    }
5}
6
7class MyComponent extends React.Component {
8    render() {
9        return (
10            <MySubComponent display={true} />
11        )
12    }
13}
14