This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The add()
method of the Cache
interface takes a URL, retrieves it and adds the resulting response object to the given cache. The add()
method is functionally equivalent to the following:
fetch(url).then(function (response) { if (!response.ok) { throw new TypeError('bad response status'); } return cache.put(url, response); })
For more complex operations, you'll need to use Cache.put()
directly.
Note: add()
will overwrite any key/value pair previously stored in the cache that matches the request.
Note: Initial Cache implementations (in both Blink and Gecko) resolve Cache.add
, Cache.addAll
, and Cache.put
promises when the response body is fully written to storage. More recent spec versions have newer language stating 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.add(request).then(function() { //request has been added to the cache });
Parameters
- request
- The request you want to add to the cache. This can be a
Request
object or a URL.
Returns
A Promise
that resolves with void.
Exceptions
Exception | Happens when |
---|---|
TypeError |
The URL scheme is not The Response status is not in the 200 range (i.e., not a successful response.) This occurs if the request does not return successfully, but also if the request is a cross-origin no-cors request (in which case the reported status is always 0.) |
Examples
This code block waits for an InstallEvent
to fire, then runs waitUntil
to handle the install process for the app. This consists of calling CacheStorage.open
to create a new cache, then using Cache.add
to add an asset to it.
this.addEventListener('install', function(event) { event.waitUntil( caches.open('v1').then(function(cache) { return cache.add('/sw-test/index.html'); }) ); });
Specifications
Specification | Status | Comment |
---|---|---|
Service Workers The definition of 'Cache' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 46.0 | (Yes)[1] | No support | 24 | No support |
Require HTTPS | 46.0 | (Yes)[1] | ? | ? | ? |
TypeError if request is not successful |
(Yes) | 47.0 (47.0)[1] | (Yes) | (Yes) | (Yes) |
Feature | Android | Android Webview | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|---|
Basic support | No support | No support | (Yes) | ? | No support | ? | No support | 46.0 |
Require HTTPS | No support | No support | (Yes) | ? | ? | ? | ? | 46.0 |
TypeError if request is not successful |
(Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
[1] Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)