service-worker.js

// Listen for install event, set callback
self.addEventListener('install', function(event) {
    // Perform some task
    event.waitUntil(
      caches.open('pdinstall-static-v4').then(function(cache) {
        return cache.addAll([
          '/lib/images/icon-192.png',
          '/lib/images/icon-512.png',
          '/lib/style/calendar.css',
          '/lib/style/main.css',
          '/lib/scripts/swiped-events.js'
          // '/index.html',
          // '/'
        ]);
      })
    );
});

self.addEventListener('activate', function(event) {
  event.waitUntil(
    caches.keys().then(function(cacheNames) {
      return Promise.all(
        cacheNames.filter(function(cacheName) {
          // Return true if you want to remove this cache,
          // but remember that caches are shared across
          // the whole origin
          // return true;
        })
        .map(function(cacheName) {
          return caches.delete(cacheName);
        })
      );
    })
  );
});

self.addEventListener('fetch', function(event) {
  event.respondWith(
    caches.open('pdinstall-dynamic').then(function(cache) {
      return cache.match(event.request).then(function (response) {
        return fetch(event.request)
        .then(function(response) {
          if (event.request.method == 'POST') {
            return response;
          }
          cache.put(event.request, response.clone());
          return response;
        })
        .catch(() => {
          return response;
        });
      });
    })
  );
});