service-worker.js

const CACHE_NAME = 'app-cache-v1';
const FILES_TO_CACHE = [
  // i was caching things, but that meant that when I updated the app (frequently) those updates wouldnt send...
        '/img/android-chrome-192x192.png',
        '/img/android-chrome-512x512.png',
        '/img/apple-touch-icon.png'
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      return cache.addAll(FILES_TO_CACHE);
    })
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((keyList) => {
      return Promise.all(
        keyList.map((key) => {
          if (key !== CACHE_NAME) {
            return caches.delete(key);
          }
        })
      );
    })
  );
  self.clients.claim();
});

self.addEventListener('fetch', (event) => {
  if (event.request.url.includes('leaderboard.json')) { // fetch new versions of leaderboard, every time.
    event.respondWith(fetch(event.request));
  } else {
    event.respondWith(
      caches.match(event.request).then((response) => {
        return response || fetch(event.request);
      })
    );
  }
});