2 files changed, 56 insertions, 1 deletions
diff --git a/assets/sw-register.js b/assets/sw-register.js
index 583532c..0b71f03 100644
--- a/assets/sw-register.js
+++ b/assets/sw-register.js
@@ -1,6 +1,7 @@
+{{ $swJS := resources.Get "sw.js" | resources.ExecuteAsTemplate "sw.js" . }}
 if (navigator.serviceWorker) {
   navigator.serviceWorker.register(
-    "{{ "/sw.js" | relURL }}", 
+    "{{ $swJS.RelPermalink }}", 
     { scope: "{{ "/" | relURL }}" }
   );
 }
diff --git a/assets/sw.js b/assets/sw.js
new file mode 100644
index 0000000..d7d517a
--- /dev/null
+++ b/assets/sw.js
@@ -0,0 +1,54 @@
+const cacheName = self.location.pathname
+const pages = [
+  {{ range .Site.AllPages -}}
+  "{{ .RelPermalink }}",
+  {{ end }}
+];
+
+self.addEventListener("install", function (event) {
+  self.skipWaiting();
+
+  const precache = caches.open(cacheName).then((cache) => {
+    return cache.addAll(pages);
+  });
+  event.waitUntil(precache);
+});
+
+self.addEventListener("fetch", (event) => {
+  const request = event.request;
+  if (request.method !== "GET") {
+    return;
+  }
+
+  /**
+   * @param {Response} response
+   * @returns {Promise<Response>}
+   */
+  function saveToCache(response) {
+    if (cacheable(response)) {
+      return caches
+        .open(cacheName)
+        .then((cache) => cache.put(request, response.clone()))
+        .then(() => response);
+    } else {
+      return response;
+    }
+  }
+
+  /**
+   * @param {Error} error
+   */
+  function serveFromCache(error) {
+    return caches.open(cacheName).then((cache) => cache.match(request.url));
+  }
+
+  /**
+   * @param {Response} response
+   * @returns {Boolean}
+   */
+  function cacheable(response) {
+    return response.type === "basic" && response.ok && !response.headers.has("Content-Disposition")
+  }
+
+  event.respondWith(fetch(request).then(saveToCache).catch(serveFromCache));
+});