WIP - add extractor, generate snippet_data

node_modules/workbox-navigation-preload/enable.mjs

@@ -0,0 +1,56 @@
+/*
+  Copyright 2017 Google Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      https://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+import {logger} from 'workbox-core/_private/logger.mjs';
+
+import {isSupported} from './utils/isSupported.mjs';
+
+import './_version.mjs';
+
+/**
+ * If the browser supports Navigation Preload, then this will enable it.
+ *
+ * @param {string} [headerValue] Optionally, allows developers to
+ * [override](https://developers.google.com/web/updates/2017/02/navigation-preload#changing_the_header)
+ * the value of the `Service-Worker-Navigation-Preload` header which will be
+ * sent to the server when making the navigation request.
+ *
+ * @memberof workbox.navigationPreload
+ */
+function enable(headerValue) {
+  if (isSupported()) {
+    self.addEventListener('activate', (event) => {
+        event.waitUntil(
+          self.registration.navigationPreload.enable().then(() => {
+            // Defaults to Service-Worker-Navigation-Preload: true if not set.
+            if (headerValue) {
+              self.registration.navigationPreload.setHeaderValue(headerValue);
+            }
+
+            if (process.env.NODE_ENV !== 'production') {
+              logger.log(`Navigation preload is enabled.`);
+            }
+          })
+        );
+    });
+  } else {
+    if (process.env.NODE_ENV !== 'production') {
+      logger.log(`Navigation preload is not supported in this browser.`);
+    }
+  }
+}
+
+export {enable};