service-worker.js

const CACHE_NAME = 'todo-app-v2';
const ASSETS = [
    '/',
    '/index.html',
    '/styles.css',
    '/app.js',
    '/manifest.json',
    '/icon.png'
];

self.addEventListener('install', event => {
    event.waitUntil(
        caches.open(CACHE_NAME).then(cache => {
            return cache.addAll(ASSETS);
        })
    );
});

self.addEventListener('fetch', event => {
    event.respondWith(
        caches.match(event.request).then(response => {
            return response || fetch(event.request);
        })
    );
});

self.addEventListener('activate', event => {
    event.waitUntil(
        caches.keys().then(keys => {
            return Promise.all(
                keys.filter(key => key !== CACHE_NAME).map(key => caches.delete(key))
            );
        })
    );
});

// Handle Push Notifications
self.addEventListener('push', event => {
    const data = event.data ? event.data.text() : 'Default Notification';
    const options = {
        body: 'You have a new notification.',
        icon: 'icon.png'
    };
    event.waitUntil(
        self.registration.showNotification(data, options)
    );
});

// Background Sync
self.addEventListener('sync', event => {
    if (event.tag === 'sync-tasks') {
        event.waitUntil(
            // Simulate syncing tasks with a server
            new Promise(resolve => {
                console.log('Syncing tasks with the server...');
                setTimeout(resolve, 3000);
            }).then(() => console.log('Tasks synced successfully.'))
        );
    }
});