Add public/sw.js

public/sw.js

@@ -0,0 +1,68 @@
+const CACHE_VERSION = 'v1';
+const CACHE_NAME = `portfolio-cache-${CACHE_VERSION}`;
+
+const URLS_TO_CACHE = [
+  '/',
+  '/index.html',
+  '/manifest.json'
+];
+
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    caches.open(CACHE_NAME).then((cache) => {
+      return cache.addAll(URLS_TO_CACHE);
+    })
+  );
+  self.skipWaiting();
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    caches.keys().then((cacheNames) => {
+      return Promise.all(
+        cacheNames
+          .filter((cacheName) => cacheName !== CACHE_NAME)
+          .map((cacheName) => caches.delete(cacheName))
+      );
+    })
+  );
+  self.clients.claim();
+});
+
+self.addEventListener('fetch', (event) => {
+  const { request } = event;
+  const url = new URL(request.url);
+
+  if (request.method !== 'GET') {
+    return;
+  }
+
+  if (url.protocol !== 'http:' && url.protocol !== 'https:') {
+    return;
+  }
+
+  event.respondWith(
+    caches.match(request).then((cachedResponse) => {
+      if (cachedResponse) {
+        return cachedResponse;
+      }
+
+      return fetch(request)
+        .then((response) => {
+          if (!response || response.status !== 200 || response.type === 'error') {
+            return response;
+          }
+
+          const responseToCache = response.clone();
+          caches.open(CACHE_NAME).then((cache) => {
+            cache.put(request, responseToCache);
+          });
+
+          return response;
+        })
+        .catch(() => {
+          return caches.match('/index.html');
+        });
+    })
+  );
+});