sw.js

/*
 * @license
 * Your First PWA Codelab (https://g.co/codelabs/pwa)
 * Copyright 2019 Google Inc. All rights reserved.
 *
 * 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
 */
'use strict';

// CODELAB: Update cache names any time any of the cached files change.
const CACHE_NAME = '5a13cbd5a1b914d72958f64c10504aa5dc8635c3';

// CODELAB: Add list of files to cache here.
const FILES_TO_CACHE = [
    'index.html',
    'db.json',
];

self.addEventListener('install', (evt) => {
    console.log('[ServiceWorker] Install');
    // CODELAB: Precache static resources here.
    evt.waitUntil(
        caches.open(CACHE_NAME).then((cache) => {
            console.log('[ServiceWorker] Pre-caching offline page');
            return cache.addAll(FILES_TO_CACHE);
        })
    );
    self.skipWaiting();
});

self.addEventListener('activate', (evt) => {
    console.log('[ServiceWorker] Activate');
    // CODELAB: Remove previous cached data from disk.
    evt.waitUntil(
        caches.keys().then((keyList) => {
            return Promise.all(keyList.map((key) => {
                if (key !== CACHE_NAME) {
                    console.log('[ServiceWorker] Removing old cache', key);
                    return caches.delete(key);
                }
            }));
        })
    );
    self.clients.claim();
});

self.addEventListener('fetch', (evt) => {
    console.log('[ServiceWorker] Fetch', evt.request.url);
    // CODELAB: Add fetch event handler here.
    if (evt.request.mode !== 'navigate') {
        // Not a page navigation, bail.
        return;
    }
    evt.respondWith(
        fetch(evt.request)
            .catch(() => {
                return caches.open(CACHE_NAME)
                    .then((cache) => {
                        return cache.match('offline.html');
                    });
            })
    );
});