import React, { useEffect } from 'react' import ReactDOM from 'react-dom' const App = () => { // This effect runs once, after the first render useEffect(() => { document.title = "This is a title" }, []) return <h1>Hello, World!</h1> }; ReactDOM.render( <App />, document.getElementById('root') );
import React from 'react' import ReactDOM from 'react-dom' class Doc extends React.Component{ componentDidMount(){ document.title = "dfsdfsdfsd" } render(){ return( <b> test </b> ) } } ReactDOM.render( <Doc />, document.getElementById('container') );