feat: add PWA support - manifest, service worker, offline page, icons

public/sw.js

@@ -0,0 +1,71 @@
+const CACHE = 'sm-v1';
+const STATIC_ASSETS = [
+  '/assets/css/style.css',
+  '/assets/js/app.js',
+  '/assets/js/main.js',
+  '/assets/img/server.svg',
+  '/assets/img/icon-192.png',
+  '/assets/img/icon-512.png',
+  '/manifest.json',
+  '/offline',
+];
+
+self.addEventListener('install', function(e) {
+  e.waitUntil(
+    caches.open(CACHE).then(function(cache) {
+      return cache.addAll(STATIC_ASSETS);
+    }).then(function() {
+      return self.skipWaiting();
+    })
+  );
+});
+
+self.addEventListener('activate', function(e) {
+  e.waitUntil(
+    caches.keys().then(function(keys) {
+      return Promise.all(
+        keys.filter(function(k) { return k !== CACHE; }).map(function(k) { return caches.delete(k); })
+      );
+    }).then(function() {
+      return self.clients.claim();
+    })
+  );
+});
+
+self.addEventListener('fetch', function(e) {
+  var url = new URL(e.request.url);
+
+  if (url.pathname.startsWith('/api/')) {
+    return;
+  }
+
+  if (
+    url.pathname.startsWith('/assets/') ||
+    url.pathname === '/manifest.json'
+  ) {
+    e.respondWith(
+      caches.open(CACHE).then(function(cache) {
+        return cache.match(e.request).then(function(cached) {
+          var fetchPromise = fetch(e.request).then(function(response) {
+            cache.put(e.request, response.clone());
+            return response;
+          });
+          return cached || fetchPromise;
+        });
+      })
+    );
+    return;
+  }
+
+  e.respondWith(
+    fetch(e.request).catch(function() {
+      return caches.match(e.request).then(function(cached) {
+        if (cached) return cached;
+        if (e.request.mode === 'navigate') {
+          return caches.match('/offline');
+        }
+        return new Response('Offline', { status: 503 });
+      });
+    })
+  );
+});