gulp-sw-cache/template/sw.js

Add Offline cache for webapp

var staticCacheName = '<%= version %>';

self.addEventListener('install', function(event) {
  event.waitUntil(
    caches.open(staticCacheName).then(function(cache) {
      return cache.addAll(<%- JSON.stringify(files) %>);
    })
  );
});

self.addEventListener('activate', function(event) {
  event.waitUntil(
    caches.keys().then(function(cacheNames) {
      return Promise.all(
        cacheNames.filter(function(cacheName) {
          return cacheName.startsWith('<%= versionPrefix %>') &&
                 cacheName != staticCacheName;
        }).map(function(cacheName) {
          return caches.delete(cacheName);
        })
      );
    })
  );
});

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

self.addEventListener('message', function(event) {
  if (event.data.action === 'skipWaiting') {
    self.skipWaiting();
  }
});