Add SW registration template injection (#21)

template/build/service-worker-dev.js

@@ -0,0 +1,17 @@
+// This service worker file is effectively a 'no-op' that will reset any
+// previous service worker registered for the same host:port combination.
+// In the production build, this file is replaced with an actual service worker
+// file that will precache your site's local assets.
+// See https://github.com/facebookincubator/create-react-app/issues/2272#issuecomment-302832432
+
+self.addEventListener('install', () => self.skipWaiting());
+
+self.addEventListener('activate', () => {
+  self.clients.matchAll({ type: 'window' }).then(windowClients => {
+    for (let windowClient of windowClients) {
+      // Force open pages to refresh, so that they have a chance to load the
+      // fresh navigation response from the local dev server.
+      windowClient.navigate(windowClient.url);
+    }
+  });
+});

template/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);
+        });
+      }
+  });
+})();

template/build/webpack.dev.conf.js

@@ -1,3 +1,5 @@
+var fs = require('fs')
+var path = require('path')
 var utils = require('./utils')
 var webpack = require('webpack')
 var config = require('../config')
@@ -28,7 +30,9 @@ module.exports = merge(baseWebpackConfig, {
     new HtmlWebpackPlugin({
       filename: 'index.html',
       template: 'index.html',
-      inject: true
+      inject: true,
+      serviceWorkerLoader: `<script>${fs.readFileSync(path.join(__dirname,
+        './service-worker-dev.js'), 'utf-8')}</script>`
     }),
     new FriendlyErrorsPlugin()
   ]

template/build/webpack.prod.conf.js

@@ -1,3 +1,4 @@
+var fs = require('fs')
 var path = require('path')
 var utils = require('./utils')
 var webpack = require('webpack')
@@ -66,7 +67,9 @@ var webpackConfig = merge(baseWebpackConfig, {
         // https://github.com/kangax/html-minifier#options-quick-reference
       },
       // necessary to consistently work with multiple chunks via CommonsChunkPlugin
-      chunksSortMode: 'dependency'
+      chunksSortMode: 'dependency',
+      serviceWorkerLoader: `<script>${fs.readFileSync(path.join(__dirname,
+        './service-worker-prod.js'), 'utf-8')}</script>`
     }),
     // split vendor js into its own file
     new webpack.optimize.CommonsChunkPlugin({

template/index.html

@@ -28,63 +28,7 @@
   <body>
     <div id="app">This is your fallback content in case JavaScript fails to load.</div>
     <!-- Todo: only include in production -->
-    <script>
-      (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);
-              });
-            }
-        });
-      })();
-    </script>
+    <%= htmlWebpackPlugin.options.serviceWorkerLoader %>
     <!-- built files will be auto injected -->
   </body>
 </html>