The put() method of the Cache interface allows key/value pairs to be added to the current Cache object.

Often, you will just want to fetch() one or more requests, then add the result straight to your cache. In such cases you are better off using Cache.add()/Cache.addAll(), as they are shorthand functions for one or more of these operations.

fetch(url).then((response) => {
  if (!response.ok) {
    throw new TypeError("Bad response status");
  }
  return cache.put(url, response);
});

request

The Request object or URL that you want to add to the cache.

response

The Response you want to match up to the request.

A Promise that resolves with undefined.

TypeError

Returned if the URL scheme is not http or https.

This example is from the MDN simple-service-worker example (see simple-service-worker running live). Here we wait for a FetchEvent to fire. We construct a custom response like so:

1. Check whether a match for the request is found in the CacheStorage using CacheStorage.match(). If so, serve that.
2. If not, open the v1 cache using open(), put the default network request in the cache using Cache.put() and return a clone of the default network request using return response.clone(). Clone is needed because put() consumes the response body.
3. If this fails (e.g., because the network is down), return a fallback response.

let response;
const cachedResponse = caches
  .match(event.request)
  .catch(() => fetch(event.request))
  .then((r) => {
    response = r;
    caches.open("v1").then((cache) => {
      cache.put(event.request, response);
    });
    return response.clone();
  })
  .catch(() => caches.match("/gallery/myLittleVader.jpg"));

• Using Service Workers
• Cache
• caches