import 7b usebeforeunload 7d from 27react beforeunload

1window.addEventListener('beforeunload', (event) => {
2  event.returnValue = `Are you sure you want to leave?`;
3});
4

1let formChanged = false;
2myForm.addEventListener('change', () => formChanged = true);
3window.addEventListener('beforeunload', (event) => {
4  if (formChanged) {
5    event.returnValue = 'You have unfinished changes!';
6  }
7});
8

1useBeforeunload(() => "You'll lose your data!");
2

1import { useBeforeunload } from 'react-beforeunload';
2

1useBeforeunload((event) => event.preventDefault());
2