Create sw.js

sw.js

@@ -0,0 +1,79 @@
+const CACHE_NAME = 'melofy-cache-v1';
+const urlsToCache = [
+  '/',
+  '/index.html'
+  // Add other static assets here if they are not inlined, e.g., '/style.css'
+];
+
+// Install event: caches the core application shell.
+self.addEventListener('install', event => {
+  event.waitUntil(
+    caches.open(CACHE_NAME)
+      .then(cache => {
+        console.log('Opened cache');
+        return cache.addAll(urlsToCache);
+      })
+  );
+  self.skipWaiting();
+});
+
+// Fetch event: serves assets from cache first for offline capability.
+self.addEventListener('fetch', event => {
+  // We only want to cache GET requests.
+  if (event.request.method !== 'GET') {
+    return;
+  }
+
+  event.respondWith(
+    caches.match(event.request)
+      .then(response => {
+        // Cache hit - return response
+        if (response) {
+          return response;
+        }
+
+        // Not in cache - fetch from network, then cache it.
+        return fetch(event.request).then(
+          response => {
+            // Check if we received a valid response
+            if(!response || response.status !== 200 || response.type !== 'basic') {
+              return response;
+            }
+
+            // IMPORTANT: Clone the response. A response is a stream
+            // and can only be consumed once. We need one for the browser
+            // and one for the cache.
+            const responseToCache = response.clone();
+
+            caches.open(CACHE_NAME)
+              .then(cache => {
+                // We don't cache API calls to avoid stale data.
+                // Adjust this condition if you have other API endpoints.
+                if (!event.request.url.includes('/search/') && !event.request.url.includes('/lyrics')) {
+                    cache.put(event.request, responseToCache);
+                }
+              });
+
+            return response;
+          }
+        );
+      })
+    );
+});
+
+// Activate event: cleans up old caches.
+self.addEventListener('activate', event => {
+  const cacheWhitelist = [CACHE_NAME];
+  event.waitUntil(
+    caches.keys().then(cacheNames => {
+      return Promise.all(
+        cacheNames.map(cacheName => {
+          if (cacheWhitelist.indexOf(cacheName) === -1) {
+            return caches.delete(cacheName);
+          }
+        })
+      );
+    })
+  );
+  return self.clients.claim();
+});