Added service worker

app/client/main.js

@@ -1,3 +1,4 @@
 import '/imports/ui/vueSetup.js';
 import '/imports/ui/styles/stylesIndex.js';
 import '/imports/client/config.js';
+import '/imports/client/serviceWorker.js';

app/imports/client/serviceWorker.js

@@ -0,0 +1,5 @@
+Meteor.startup(() => {
+  navigator.serviceWorker.register('/sw.js')
+  .then()
+  .catch(error => console.log('ServiceWorker registration failed: ', error));
+});

app/public/sw.js

@@ -0,0 +1,95 @@
+const HTMLToCache = '/';
+const version = 'MSW V0.3';
+
+self.addEventListener('install', (event) => {
+  event.waitUntil(caches.open(version).then((cache) => {
+    cache.add(HTMLToCache).then(self.skipWaiting());
+  }));
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+  caches.keys().then(cacheNames => Promise.all(cacheNames.map((cacheName) => {
+    if (version !== cacheName) return caches.delete(cacheName);
+  }))).then(self.clients.claim())
+  );
+});
+
+self.addEventListener('fetch', (event) => {
+  // only processes http:// & https:// requests, prevents chrome-extention:// errors
+  if (event.request.url.startsWith('http')){
+
+    const requestToFetch = event.request.clone();
+    event.respondWith(
+    caches.match(event.request.clone()).then((cached) => {
+      // We don't return cached HTML (except if fetch failed)
+      if (cached) {
+        const resourceType = cached.headers.get('content-type');
+        // We only return non css/js/html cached response e.g images
+        if (!hasHash(event.request.url) && !/text\/html/.test(resourceType)) {
+          return cached;
+        }
+
+        // If the CSS/JS didn't change since it's been cached, return the cached version
+        if (hasHash(event.request.url) && hasSameHash(event.request.url, cached.url)) {
+          return cached;
+        }
+      }
+      return fetch(requestToFetch).then((response) => {
+        const clonedResponse = response.clone();
+        const contentType = clonedResponse.headers.get('content-type');
+
+        if (!clonedResponse || clonedResponse.status !== 200 || clonedResponse.type !== 'basic'
+        || /\/sockjs\//.test(event.request.url)) {
+          return response;
+        }
+
+        if (/html/.test(contentType)) {
+          caches.open(version).then(cache => cache.put(HTMLToCache, clonedResponse));
+        } else {
+          // Delete old version of a file
+          if (hasHash(event.request.url)) {
+            caches.open(version).then(cache => cache.keys().then(keys => keys.forEach((asset) => {
+              if (new RegExp(removeHash(event.request.url)).test(removeHash(asset.url))) {
+                cache.delete(asset);
+              }
+            })));
+          }
+
+          caches.open(version).then(cache => cache.put(event.request, clonedResponse));
+        }
+        return response;
+      }).catch(() => {
+        if (hasHash(event.request.url)) return caches.match(event.request.url);
+        // If the request URL hasn't been served from cache and isn't sockjs we suppose it's HTML
+        else if (!/\/sockjs\//.test(event.request.url)) return caches.match(HTMLToCache);
+        // Only for sockjs
+        return new Response('No connection to the server', {
+          status: 503,
+          statusText: 'No connection to the server',
+          headers: new Headers({ 'Content-Type': 'text/plain' }),
+        });
+      });
+    })
+    );
+
+  }
+
+});
+
+function removeHash(element) {
+  if (typeof element === 'string') return element.split('?hash=')[0];
+}
+
+function hasHash(element) {
+  if (typeof element === 'string') return /\?hash=.*/.test(element);
+}
+
+function hasSameHash(firstUrl, secondUrl) {
+  if (typeof firstUrl === 'string' && typeof secondUrl === 'string') {
+    return /\?hash=(.*)/.exec(firstUrl)[1] === /\?hash=(.*)/.exec(secondUrl)[1];
+  }
+}
+
+// Service worker created by Ilan Schemoul alias NitroBAY as a specific Service Worker for Meteor
+// Please see https://github.com/NitroBAY/meteor-service-worker for the official project source