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- /*
- 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};
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