radish/build/lib/sw.js

Radish is a React-based static site generator that outputs plain HTML and CSS.

const VERSION = "v1";
const PAGES_CACHE = `pages_${VERSION}`;
const ASSET_CACHE = `assets_${VERSION}`;
const CACHES = new Set([PAGES_CACHE, ASSET_CACHE]);
const SW_CACHE_KEY = "sw-cache-expires";
const DEFAULT_MAX_AGE = 0;
const DEFAULT_PUBLIC_MAX_AGE = 31_557_600;
self.addEventListener("activate", event => {
    event.waitUntil(caches
        .keys()
        .then(keys => {
        const deletes = keys
            .filter(key => !CACHES.has(key))
            .map(key => caches.delete(key));
        return Promise.all(deletes);
    })
        .then(() => self.clients.claim()));
});
self.addEventListener("fetch", event => {
    event.respondWith(caches.match(event.request.url).then(cached => {
        const expires = Number(cached?.headers.get(SW_CACHE_KEY));
        if (cached && new Date().getTime() / 1000 < expires)
            return cached;
        const url = new URL(event.request.url);
        const isPublic = url.pathname.startsWith(PUBLIC_PATH);
        const fresh = fetch(event.request)
            .then(res => {
            if (!res || res.status !== 200 || res.type !== "basic")
                return res;
            const control = cacheControl(res.headers.get("cache-control") || "");
            if (control["no-store"])
                return res;
            const defaultMaxAge = isPublic
                ? DEFAULT_PUBLIC_MAX_AGE
                : DEFAULT_MAX_AGE;
            const maxAge = control["max-age"] ?? defaultMaxAge, expires = Math.trunc(new Date().getTime() / 1000) + maxAge;
            const clone = res.clone();
            const headers = [...clone.headers, [SW_CACHE_KEY, "" + expires]];
            caches.open(isPublic ? ASSET_CACHE : PAGES_CACHE).then(cache => {
                cache.put(event.request.url, new Response(clone.body, { headers }));
            });
            return res;
        })
            .catch(() => cached || new Response("Page not available."));
        return fresh;
    }));
});
function cacheControl(header) {
    const result = {};
    if (!header)
        return {};
    const directives = header.split(/, ?/).map(val => val.split("="));
    for (const [key, val] of directives) {
        if (!key)
            continue;
        result[key] = val ? Number(val) : 1;
    }
    return result;
}
export {};