Added basic service-worker support

.netlify/state.json

@@ -0,0 +1,3 @@
+{
+	"siteId": "492c17c8-1ecc-479f-8abc-7eb13736dfb9"
+}

index.html

@@ -9,6 +9,8 @@
   <meta name="description" content="Animal Crossing - Turnip Prophet">
   <meta name="author" content="Mike Bryant">
 
+  <link rel="manifest" href="/manifest.json">
+  <link rel="apple-touch-icon" href="/img/192.png">
   <link rel="stylesheet" href="css/styles.css">
 
   <!-- Global site tag (gtag.js) - Google Analytics -->
@@ -293,6 +295,28 @@
   <script src="js/predictions.js"></script>
   <script src="js/scripts.js"></script>
   <script src="js/contributors.js"></script>
+  <script>
+    // Check compatibility for the browser we're running this in
+    if ("serviceWorker" in navigator) {
+      if (navigator.serviceWorker.controller) {
+        console.log(
+          "[PWA] Service Worker already found, skipping register"
+        );
+      } else {
+        // Register the service worker
+        navigator.serviceWorker
+          .register("/service-worker.js", {
+            scope: "./",
+          })
+          .then(function (reg) {
+            console.log(
+              "[PWA] Service worker has been registered for scope: " +
+                reg.scope
+            );
+          });
+      }
+    }
+  </script>
 </body>
 
 </html>

manifest.json

@@ -0,0 +1,19 @@
+{
+	"name": "Turnip Prophet - ACNH Turnip Tracker",
+	"short_name": "Turnip Prophet",
+	"description": "An app to track your Animal Crossing: New Horizons turnip prices daily!",
+	"start_url": "index.html",
+	"display": "standalone",
+	"background_color": "#def2d9",
+	"theme_color": "#def2d9",
+	"icons": [
+		{
+			"src": "/img/192.png",
+			"sizes": "192x192"
+		},
+		{
+			"src": "/img/512.png",
+			"sizes": "512x512"
+		}
+	]
+}

service-worker.js

@@ -0,0 +1,89 @@
+// PWA Code adapted from https://github.com/pwa-builder/PWABuilder
+const CACHE = "pwa-precache";
+const precacheFiles = [
+	"/index.html",
+	"/js/predictions.js",
+	"/js/scripts.js",
+	"/css/styles.css",
+];
+
+self.addEventListener("install", function (event) {
+	console.log("[PWA] Install Event processing");
+
+	console.log("[PWA] Skip waiting on install");
+	self.skipWaiting();
+
+	event.waitUntil(
+		caches.open(CACHE).then(function (cache) {
+			console.log("[PWA] Caching pages during install");
+			return cache.addAll(precacheFiles);
+		})
+	);
+});
+
+// Allow sw to control of current page
+self.addEventListener("activate", function (event) {
+	console.log("[PWA] Claiming clients for current page");
+	event.waitUntil(self.clients.claim());
+});
+
+// If any fetch fails, it will look for the request in the cache and serve it from there first
+self.addEventListener("fetch", function (event) {
+	if (event.request.method !== "GET") return;
+
+	event.respondWith(
+		fromCache(event.request).then(
+			(response) => {
+				// The response was found in the cache so we responde with it and update the entry
+
+				// This is where we call the server to get the newest version of the
+				// file to use the next time we show view
+				event.waitUntil(
+					fetch(event.request).then(function (response) {
+						return updateCache(event.request, response);
+					})
+				);
+
+				return response;
+			},
+			() => {
+				// The response was not found in the cache so we look for it on the server
+				return fetch(event.request)
+					.then(function (response) {
+						// If request was success, add or update it in the cache
+						event.waitUntil(
+							updateCache(event.request, response.clone())
+						);
+
+						return response;
+					})
+					.catch(function (error) {
+						console.log(
+							"[PWA] Network request failed and no cache." + error
+						);
+					});
+			}
+		)
+	);
+});
+
+function fromCache(request) {
+	// Check to see if you have it in the cache
+	// Return response
+	// If not in the cache, then return
+	return caches.open(CACHE).then(function (cache) {
+		return cache.match(request).then(function (matching) {
+			if (!matching || matching.status === 404) {
+				return Promise.reject("no-match");
+			}
+
+			return matching;
+		});
+	});
+}
+
+function updateCache(request, response) {
+	return caches.open(CACHE).then(function (cache) {
+		return cache.put(request, response);
+	});
+}