sw.js

const CACHE_VERSION = "{{COMMIT_SHA}}"; // value will be set by CD
const urlsToCache = ["{{CACHE_URLS}}"]; // value will be set by CD

urlsToCache.push('/')
urlsToCache.push('/datenschutz.html')


var CURRENT_CACHES = {
  prefetch: 'frustrated-cache-v' + CACHE_VERSION
};

self.addEventListener('install', function(event) {
  var now = Date.now();

  console.log('Handling install event. Resources to prefetch:', urlsToCache);
event.waitUntil(
    caches.open(CURRENT_CACHES.prefetch).then(function(cache) {
      var cachePromises = urlsToCache.map(function(urlToPrefetch) {
        var url = new URL(urlToPrefetch, location.href);
        url.search += (url.search ? '&' : '?') + 'cache-bust=' + now;

        var request = new Request(url, {
          mode: 'no-cors'
        });
        return fetch(request).then(function(response) {
          if (response.status >= 400) {
            throw new Error('request for ' + urlToPrefetch +
              ' failed with status ' + response.statusText);
          }
          // Use the original URL without the cache-busting parameter as the key for cache.put().
          return cache.put(urlToPrefetch, response);
        }).catch(function(error) {
          console.error('Not caching ' + urlToPrefetch + ' due to ' + error);
        });
      });

      return Promise.all(cachePromises).then(function() {
        console.log('Pre-fetching complete.');
      });
    }).catch(function(error) {
      console.error('Pre-fetching failed:', error);
    })
  );
});



self.addEventListener('activate', function(event) {
  var expectedCacheNames = Object.keys(CURRENT_CACHES).map(function(key) {
    return CURRENT_CACHES[key];
  });
  event.waitUntil(
    caches.keys().then(function(cacheNames) {
      return Promise.all(
        cacheNames.map(function(cacheName) {
          if (expectedCacheNames.indexOf(cacheName) === -1) {
            // If this cache name isn't present in the array of "expected" cache names, then delete it.
            console.log('Deleting out of date cache:', cacheName);
            return caches.delete(cacheName);
          }
        })
      );
    })
  );
});

self.addEventListener('fetch', function(event) {
  event.respondWith(
    caches.match(event.request).then(function(response) {
      return response || fetch(event.request);
    })
  );
});