var cacheName = "test";

self.addEventListener("install", event => {
    event.waitUntil(
        caches.open(cacheName)
            .then(cache => cache.addAll([
                "/index.html",
                "/public/script/y.js",
            ]))
    );
});

self.addEventListener("activate", event => {
    event.waitUntil(
        caches.keys().then(cacheNames => {
            return Promise.all(
                cacheNames.filter(cn => {
                    return cn !== cacheName;
                }).map(cn => {
                    return caches.delete(cn);
                })
            )
        })
    )
})

self.addEventListener("fetch", event => {
    if (event.request.method === "GET") {
        event.respondWith(
            caches.match(event.request)
            .then(response => {
                if (response) {
                    return response;
                }

                var requestToCache = event.request.clone();

                return fetch(requestToCache).then(response => {
                    if (!response || response.status !== 200) {
                        return response;
                    }

                    var responseToCache = response.clone();

                    caches.open(cacheName).then(cache => {
                        cache.put(requestToCache, responseToCache);
                    });

                    return response;
                })
            })
        );
    }
    
});