sw.js

var CACHE_NAME = 'wavesafrica-org-cache-v1';

self.addEventListener('fetch', function(event) {
  event.respondWith(
    caches.match(event.request)
      .then(function(response) {
        // Cache hit - return response
        if (response) {
          return response;
        }

        return fetch(event.request).then(
          function(response) {
            // Check if we received a valid response
            if(!response || response.status !== 200 || response.type !== 'basic') {
              return response;
            }

            // IMPORTANT: Clone the response. A response is a stream
            // and because we want the browser to consume the response
            // as well as the cache consuming the response, we need
            // to clone it so we have two streams.
            var responseToCache = response.clone();

            caches.open(CACHE_NAME)
              .then(function(cache) {
                cache.put(event.request, responseToCache);
              });

            return response;
          }
        );
      })
    );
});

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

addEventListener('message', e => {
  if (e.data === 'skipWaiting') {
    skipWaiting();
  }
});