The keys
()
method of the CacheStorage
interface returns a Promise
that will resolve with an array containing strings corresponding to all of the named Cache
objects tracked by the CacheStorage
object in the order they were created. Use this method to iterate over a list of all Cache
objects.
You can access CacheStorage
through the global caches
property.
Syntax
caches.keys().then(function(keyList) { //do something with your keyList });
Parameters
None.
Return value
a Promise
that resolves with an array of the Cache
names inside the CacheStorage
object.
Examples
In this code snippet we wait for an activate
event, and then run a waitUntil()
block that clears up any old, unused caches before a new service worker is activated. Here we have a whitelist containing the names of the caches we want to keep (cacheWhitelist
). We return the keys of the caches in the CacheStorage
object using keys()
, then check each key to see if it is in the whitelist. If not, we delete it using CacheStorage.delete()
.
then.addEventListener('activate', function(event) {
var cacheWhitelist = ['v2'];
event.waitUntil(
caches.keys().then(function(keyList) {
return Promise.all(keyList.map(function(key) {
if (cacheWhitelist.indexOf(key) === -1) {
return caches.delete(key);
}
});
})
);
});
Specifications
Specification | Status | Comment |
Service WorkersThe definition of 'CacheStorage: keys' in that specification. | Working Draft | Initial definition. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Chrome
Full support 40 |
Edge
Full support 16 |
Firefox Full support 44 Full support 44 Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API. |
IE
No support No |
Opera
Full support 27 |
Safari
Full support 11.1 |
WebView Android
Full support 40 |
Chrome Android
Full support 40 |
Firefox Android
Full support 44 |
Opera Android
Full support 27 |
Safari iOS
Full support Yes |
Samsung Internet Android
Full support 4.0 |
Legend
- Full support
- Full support
- No support
- No support
- Experimental. Expect behavior to change in the future.'
- Experimental. Expect behavior to change in the future.
- See implementation notes.'
- See implementation notes.
See also
CacheStorage.keys() by Mozilla Contributors is licensed under CC-BY-SA 2.5.