--- title: Cache.put() slug: Web/API/Cache/put tags: - API - Cache - Experimental - Method - Reference - Service Workers - ServiceWorker - put translation_of: Web/API/Cache/put ---

{{APIRef("Service Workers API")}}{{SeeCompatTable}}

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

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

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

Note: put() will overwrite any key/value pair previously stored in the cache that matches the request.

Note: {{domxref("Cache.add")}}/{{domxref("Cache.addAll")}} do not cache responses with Response.status values that are not in the 200 range, whereas {{domxref("Cache.put")}} lets you store any request/response pair. As a result, {{domxref("Cache.add")}}/{{domxref("Cache.addAll")}} can't be used to store opaque responses, whereas {{domxref("Cache.put")}} can.

Note: Initial Cache implementations (in both Blink and Gecko) resolve {{domxref("Cache.add")}}, {{domxref("Cache.addAll")}}, and {{domxref("Cache.put")}} promises when the response body is fully written to the disk.  More recent spec versions state that the browser can resolve the promise as soon as the entry is recorded in the database even if the response body is still streaming in.

Syntax

cache.put(request, response).then(function() {
  // request/response pair has been added to the cache
});

Parameters

request
The {{domxref("Request")}} you want to add to the cache.
response
The {{domxref("Response")}} you want to match up to the request.

Return value

A {{jsxref("Promise")}} that resolves with void.

Note: The promise will reject with a TypeError if the URL scheme is not http or https.

Examples

This example is from the MDN sw-test example (see sw-test running live). Here we wait for a {{domxref("FetchEvent")}} to fire. We construct a custom response like so:

  1. Check whether a match for the request is found in the {{domxref("CacheStorage")}} using {{domxref("CacheStorage.match","CacheStorage.match()")}}. If so, serve that.
  2. If not, open the v1 cache using open(), put the default network request in the cache using {{domxref("Cache.put","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.
var response;
var cachedResponse = caches.match(event.request).catch(function() {
  return fetch(event.request);
}).then(function(r) {
  response = r;
  caches.open('v1').then(function(cache) {
    cache.put(event.request, response);
  });
  return response.clone();
}).catch(function() {
  return caches.match('/sw-test/gallery/myLittleVader.jpg');
});

Specifications

Specification Status Comment
{{SpecName('Service Workers', '#dom-cache-put', 'Cache: put')}} {{Spec2('Service Workers')}} Initial definition.

Browser compatibility

{{Compat("api.Cache.put")}}

See also