Add a base service worker to cache the audio and font files

public/scripts/movim_base.js

@@ -54,3 +54,12 @@ window.addEventListener('mouseover', onFocusedFunction);
 window.addEventListener('focus', onFocusedFunction);
 window.addEventListener('blur', function() { isFocused = false; });
 window.addEventListener('touchstart', function() { isTouch = true; }, { once: true });
+
+/**
+ * Register a service worker for the Progressive Web App
+ */
+if ('serviceWorker' in navigator) {
+    navigator.serviceWorker
+      .register('/scripts/movim_sw.js')
+      .then(() => { console.log('Service Worker Registered'); });
+  }

public/scripts/movim_sw.js

@@ -0,0 +1,48 @@
+self.addEventListener('install', (e) => {
+    e.waitUntil(
+        caches.open('movim').then((cache) => cache.addAll([
+            // Audio
+            '/theme/audio/call.ogg',
+            '/theme/audio/message.ogg',
+
+            // Fonts
+            '/theme/fonts/MaterialIcons/font.css',
+            '/theme/fonts/MaterialIcons/MaterialIconsRegular.woff2',
+            '/theme/fonts/Roboto/font.css',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmSU5fCRc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmSU5fABc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmSU5fCBc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmSU5fBxc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmSU5fCxc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmSU5fChc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmSU5fBBc4.woff2',
+            '/theme/fonts/Roboto/KFOmCnqEu92Fr1Mu72xKOzY.woff2',
+            '/theme/fonts/Roboto/KFOmCnqEu92Fr1Mu5mxKOzY.woff2',
+            '/theme/fonts/Roboto/KFOmCnqEu92Fr1Mu7mxKOzY.woff2',
+            '/theme/fonts/Roboto/KFOmCnqEu92Fr1Mu4WxKOzY.woff2',
+            '/theme/fonts/Roboto/KFOmCnqEu92Fr1Mu7WxKOzY.woff2',
+            '/theme/fonts/Roboto/KFOmCnqEu92Fr1Mu7GxKOzY.woff2',
+            '/theme/fonts/Roboto/KFOmCnqEu92Fr1Mu4mxK.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmEU9fCRc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmEU9fABc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmEU9fCBc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmEU9fBxc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmEU9fCxc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmEU9fChc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmEU9fBBc4.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmWUlfCRc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmWUlfABc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmWUlfCBc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmWUlfBxc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmWUlfCxc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmWUlfChc4EsA.woff2',
+            '/theme/fonts/Roboto/KFOlCnqEu92Fr1MmWUlfBBc4.woff2',
+        ])),
+    );
+});
+
+self.addEventListener('fetch', (e) => {
+    e.respondWith(
+        caches.match(e.request).then((response) => response || fetch(e.request)),
+    );
+});