How can I find which cache a service worker response belongs to?

Question

Given a request, how can I figure it out which cache it belongs to? match, despite searching in all caches, will only give me the cached response. I would like to retrieve both the cache object / cache's name and the cached response.

Answer 1

If you need to know the cache the response is in, I'm afraid you'll need to call match on each of the caches individually until you find one where there's a match.

The code could look something like this:

async function findCachedResponse(request) {
    const cacheKeys = await caches.keys();
    const openCaches = await Promise.all(cacheKeys.map(cacheKey => caches.open(cacheKey)));
    const matches = await Promise.all(openCaches.map(cache => cache.match(request));
    const i = matches.findIndex(match => match !== undefined);
    if (i !== -1) {
        return { cache: cacheKeys[i], response: matches[i] };
    } else {
        return undefined;
    }
}