service-worker.js

self.addEventListener('install', event => {
	event.waitUntil(async function installWaitUntil() {
		// Cache everything the app should need to run offline
		const cache = await caches.open('static-assets-v1');
		await cache.addAll([
			'index.html',
			'main.css',
			'landing-page.css',
			'main.js',
			'images/screenshot.png',
			'images/n26_csv_date_selector.png',
			'images/n26_download_csv_button.png',
			'images/n26_online_banking_link.png',
			'timeline.css',
			'timeline.js',
			'table.css',
			'table.js',
			'range-slider.css',
			'range-slider.js',
			'sampleCsv.js',
		]);
	}());
});

self.addEventListener('fetch', event => {
	event.respondWith(async function fetchRespondWith() {
		const cache = await caches.open('static-assets-v1');

		// Start fetching from network (but don't await it)
		const networkResponse = fetch(event.request).then(networkResponse => {
			cache.put(event.request, networkResponse.clone());
			return networkResponse;
		});

		// If there's a cached response, use that immediately while the fetch
		// completes and updates the cache in the background.
		const cachedResponse = await cache.match(event.request);
		if (cachedResponse) {
			return cachedResponse;
		}

		return networkResponse;
	}());
});