sw-update-hook.js

if (typeof window!=='undefined' && navigator.serviceWorker && navigator.serviceWorker.controller) {
	let reloadOnNext = false;

	let pushState = history.pushState;
	history.pushState = function(state, title, url) {
		if (reloadOnNext===true) location.href = url;
		else pushState.call(this, state, title, url);
	};

	navigator.serviceWorker.controller.addEventListener('statechange', e => {
		if (e.target.state==='redundant') {
			reloadOnNext = true;
		}
	});

	setInterval( () => {
		navigator.serviceWorker.ready.then( reg => reg.update() );
	}, 3e4);
}