add offline functionality by making this a PWA

- added favicons
- added manifest
- split javascript into main.js and elevators.js

sw.js

@@ -0,0 +1,96 @@
+const version = '0.6.0'
+const consolePrefix = `[SW v${version}]  `
+
+const cacheName = `hvvstuhl-${version}`;
+const contentToCache = [
+    '/',
+    '/index.html',
+    '/about.html',
+    '/main.js',
+    '/elevators.js',
+    '/style.css',
+    '/icons/192.png',
+    '/icons/512.png',
+    '/icons/512-maskable.png',
+    '/icons/512-transparent.png',
+    '/icons/favicon.ico',
+    '/icons/favicon.svg',
+    '/icons/favicon-maskable.svg',
+    '/icons/favicon-transparent.svg',
+    '/md_icons/bicycle.svg',
+    '/md_icons/braille.svg',
+    '/md_icons/door_sliding.svg',
+    '/md_icons/elevator.svg',
+    '/md_icons/elevator-slash.svg',
+    '/md_icons/fit_width.svg',
+    '/md_icons/height.svg',
+    '/md_icons/info.svg',
+    '/md_icons/load.svg',
+    '/md_icons/location.svg',
+    '/md_icons/location-searching.svg',
+    '/md_icons/speaker.svg',
+    '/md_icons/up-down.svg',
+    '/md_icons/wheelchair.svg',
+    '/md_icons/width.svg',
+];
+
+// Service worker Install: Cache all files
+self.addEventListener("install", (e) => {
+    console.log("[Service Worker] Wird installiert....");
+    e.waitUntil(
+        (async () => {
+            const cache = await caches.open(cacheName);
+            console.log("[Service Worker]   Cache wird aufgebaut...");
+            await cache.addAll(contentToCache);
+            console.log("[Service Worker]   FERTIG");
+        })(),
+    );
+});
+
+
+// delete old caches
+const deleteCache = async (key) => {
+    await caches.delete(key);
+};
+const deleteOldCaches = async () => {
+    const keyList = await caches.keys();
+    const cachesToDelete = keyList.filter((key) => key !== cacheName);
+    await Promise.all(cachesToDelete.map(deleteCache));
+};
+self.addEventListener("activate", (event) => {
+    event.waitUntil(
+        (async () => {
+            await deleteOldCaches()
+            await clients.claim();
+        })(),
+    );
+});
+
+
+
+// Respond with data from cache when offline
+self.addEventListener("fetch", (e) => {
+    e.respondWith(
+        (async () => {
+            const path = new URL(e.request.url).pathname
+
+            if(contentToCache.includes(path)){
+                console.log(`${consolePrefix}Anfrage: ${path}`);
+
+                const r = await caches.match(e.request);
+                if (r) {
+                    console.log(`${consolePrefix}  Im Cache gefunden.`);
+                    return r;
+                }
+                const response = await fetch(e.request);
+                const cache = await caches.open(cacheName);
+                console.log(`${consolePrefix}  Nicht gefunden. Aktualisiere Cache: ${path}`);
+                await cache.put(e.request, response.clone());
+                return response;
+            }else{
+                console.log(`${consolePrefix}Anfrage übersprungen: ${e.request.url}`);
+                return await fetch(e.request);
+            }
+        })(),
+    );
+});