Vanilla javascript toggle sidebar body overlay.

vanilla-js-toggle-sidebar-body-overlay.js

<script>	
	let burger = document.querySelector('.burger');
	let close = document.querySelector('.close');
	let sidenav = document.querySelector('#sidenav');
	let overlay = document.querySelector('#overlay');

	let classOpen = [sidenav, overlay];

	burger.addEventListener('click', function(e){
		classOpen.forEach(e => e.classList.add('active'));
	});

	let classCloseClick = [overlay, close];

	classCloseClick.forEach(function(el) {
		el.addEventListener('click', function(els) {
			classOpen.forEach(els => els.classList.remove('active'));
		});
	});
</script>