JAVASCRIPT

react extends component construtor super props

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      header: "Header from state...",
      content: "Content from state..."
    }
  }
render() {
  return (
  <>
      <h1>{this.state.header}</h1>
      <h2>{this.state.content}</h2>
      </>
    );
}
}
ReactDOM.render(
<App />,
document.getElementById ('mountNode'));

react extends component this.props

class App extends React.Component {

render() {
  return (
  <>
      <h1>{this.props.headerProps}</h1>
      <h2>{this.props.contentProps}</h2>
      </>
    );
}
}
ReactDOM.render(
<App headerProps = "Header Props" contentProps="Content PROPS"/>,
document.getElementById ('mountNode'));