add yaml frontmatter options

Author: ascott1

_config.yml

@@ -50,3 +50,7 @@ repos:
 
 # Style Variables
 brand_color: "#2cb34a"
+
+# Offline caching
+offline_cache: true
+cache_name: DOCter-v1

_layouts/default.html

@@ -49,12 +49,14 @@ <h1 class="site-title"><a class="title-link" href="{{ site.baseurl }}/">{{ site.
         </div><!--/.wrap -->
       </footer>
     </div> <!-- /.container -->
-    <script>
-      if('serviceWorker' in navigator) {
-        navigator.serviceWorker
-         .register('/sw.js')
-         .then(function() { console.log('Service Worker Registered'); });
-       }
-    </script>
+    {% if site.offline_cache == true %}
+      <script>
+        if('serviceWorker' in navigator) {
+          navigator.serviceWorker
+           .register('/sw.js')
+           .then(function() { console.log('Service Worker Registered'); });
+         }
+      </script>
+    {% endif %}
     </body>
 </html>

sw.js

@@ -4,24 +4,26 @@ layout: null
 
 importScripts('/cache-polyfill.js');
 
+var filesToCache = [
+  // root
+  '/',
+  '/index.html',
+  // css
+  '/assets/css/main.css',
+  '/assets/css/normalize.css',
+  '/assets/css/syntax.css',
+  // images
+  '/assets/img/octocat.png',
+  // pages
+  '/example_page/',
+  // posts
+  {% for post in site.posts %}'{{ post.url }}',{% endfor %}
+];
+
 self.addEventListener('install', function(e) {
   e.waitUntil(
-    caches.open('DOCter').then(function(cache) {
-      return cache.addAll([
-        // root
-        '/',
-        '/index.html',
-        // css
-        '/assets/css/main.css',
-        '/assets/css/normalize.css',
-        '/assets/css/syntax.css',
-        // images
-        '/assets/img/octocat.png',
-        // pages
-        '/example_page/',
-        // posts
-        {% for post in site.posts %}'{{ post.url }}',{% endfor %}
-      ]);
+    caches.open('{{ site.cache_name }}').then(function(cache) {
+      return cache.addAll(filesToCache);
     })
   );
 });