posimai-veil/sw.js

const CACHE  = 'posimai-veil-v3';
const ASSETS = ['/', '/index.html', '/manifest.json'];
const ORIGIN = self.location.origin;

self.addEventListener('install', e => {
    e.waitUntil(
        caches.open(CACHE).then(c => c.addAll(ASSETS))
    );
    self.skipWaiting();
});

self.addEventListener('activate', e => {
    e.waitUntil(
        caches.keys().then(keys =>
            Promise.all(keys.filter(k => k !== CACHE).map(k => caches.delete(k)))
        ).catch(err => console.warn('[SW] activate error', err))
    );
    self.clients.claim();
});

self.addEventListener('fetch', e => {
    // クロスオリジンリクエストはキャッシュしない（API等が古いデータを返すのを防ぐ）
    if (!e.request.url.startsWith(ORIGIN)) return;

    e.respondWith(
        caches.match(e.request).then(cached => cached || fetch(e.request))
    );
});