updates...

Former-commit-id: 2d19655aac80ec7033829b0b3d708bf86986252c [formerly b8bb006bd1a5492960c1d4793e15e80775ddc5fd] [formerly 4641277c14953bdb2ddab89ba866cf63f3dac0f9 [formerly 95b91a64a3c648e1414c7feb4b597bf0da195664]]
Former-commit-id: 5a6e07758bbe67fd202effa5b2975c65227eaebd [formerly 9a161548d270750b8da949189ad6f3b641779bfc]
Former-commit-id: 84e0bbcbbead53c5e91987574d5c854a9792515f

_assets/build/service-worker-prod.js

@@ -0,0 +1,55 @@
+(function() {
+  'use strict';
+
+  // Check to make sure service workers are supported in the current browser,
+  // and that the current page is accessed from a secure origin. Using a
+  // service worker from an insecure origin will trigger JS console errors.
+  const isLocalhost = Boolean(window.location.hostname === 'localhost' ||
+      // [::1] is the IPv6 localhost address.
+      window.location.hostname === '[::1]' ||
+      // 127.0.0.1/8 is considered localhost for IPv4.
+      window.location.hostname.match(
+        /^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
+      )
+    );
+
+  window.addEventListener('load', function() {
+      if ('serviceWorker' in navigator &&
+          (window.location.protocol === 'https:' || isLocalhost)) {
+        navigator.serviceWorker.register('service-worker.js')
+        .then(function(registration) {
+          // updatefound is fired if service-worker.js changes.
+          registration.onupdatefound = function() {
+            // updatefound is also fired the very first time the SW is installed,
+            // and there's no need to prompt for a reload at that point.
+            // So check here to see if the page is already controlled,
+            // i.e. whether there's an existing service worker.
+            if (navigator.serviceWorker.controller) {
+              // The updatefound event implies that registration.installing is set
+              const installingWorker = registration.installing;
+
+              installingWorker.onstatechange = function() {
+                switch (installingWorker.state) {
+                  case 'installed':
+                    // At this point, the old content will have been purged and the
+                    // fresh content will have been added to the cache.
+                    // It's the perfect time to display a "New content is
+                    // available; please refresh." message in the page's interface.
+                    break;
+
+                  case 'redundant':
+                    throw new Error('The installing ' +
+                                    'service worker became redundant.');
+
+                  default:
+                    // Ignore
+                }
+              };
+            }
+          };
+        }).catch(function(e) {
+          console.error('Error during service worker registration:', e);
+        });
+      }
+  });
+})();