noctbot/web/src/service-worker.ts

/* eslint-disable no-restricted-globals,@typescript-eslint/no-explicit-any */
// @ts-ignore -- generated package
import { timestamp, files, shell } from "@sapper/service-worker";

const ASSETS = `cache${timestamp}`;

// `shell` is an array of all the files generated by the bundler,
// `files` is an array of everything in the `static` directory
const toCache = (shell as string[]).concat(files as string[]);
const cached = new Set(toCache);

self.addEventListener("install", <EventType extends ExtendableEvent>(event: EventType) => {
    event.waitUntil(
        caches
            .open(ASSETS)
            .then((cache) => cache.addAll(toCache))
            .then(() => {
                (self as any as ServiceWorkerGlobalScope).skipWaiting();
            }),
    );
});

self.addEventListener("activate", <EventType extends ExtendableEvent>(event: EventType) => {
    event.waitUntil(
        caches.keys().then(async (keys) => {
            // delete old caches
            for (const key of keys) { // eslint-disable-line no-restricted-syntax
                if (key !== ASSETS) {
                    // eslint-disable-next-line no-await-in-loop
                    await caches.delete(key);
                }
            }

            (self as any as {clients: Clients}).clients.claim();
        }),
    );
});

self.addEventListener("fetch", <EventType extends FetchEvent>(event: EventType) => {
    if (event.request.method !== "GET" || event.request.headers.has("range")) return;

    const url = new URL(event.request.url);

    // don't try to handle e.g. data: URIs
    if (!url.protocol.startsWith("http")) return;

    // ignore dev server requests
    if (url.hostname === self.location.hostname && url.port !== self.location.port) return;

    // always serve static files and bundler-generated assets from cache
    if (url.host === self.location.host && cached.has(url.pathname)) {
        caches.match(event.request).then((match): void => {
            if (match) event.respondWith(match);
        });
        return;
    }

    // for pages, you might want to serve a shell `service-worker-index.html` file,
    // which Sapper has generated for you. It's not right for every
    // app, but if it's right for yours then uncomment this section
    /*
	if (url.origin === self.origin && routes.find(route => route.pattern.test(url.pathname))) {
		event.respondWith(caches.match('/service-worker-index.html'));
		return;
	}
	*/

    if (event.request.cache === "only-if-cached") return;

    // for everything else, try the network first, falling back to
    // cache if the user is offline. (If the pages never change, you
    // might prefer a cache-first approach to a network-first one.)
    event.respondWith(
        caches
            .open(`offline${timestamp}`)
            .then(async (cache) => {
                try {
                    const response = await fetch(event.request);
                    cache.put(event.request, response.clone());
                    return response;
                } catch (err) {
                    const response = await cache.match(event.request);
                    if (response) return response;

                    throw err;
                }
            }),
    );
});