CacheStorage.keys()
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 an allowlist
containing the names of the caches we want to keep (cacheAllowlist
). We
return the keys of the caches in the CacheStorage
object using
keys()
, then check each key to see if it is in the allowlist. If not, we
delete it using CacheStorage.delete()
.
this.addEventListener('activate', function(event) {
var cacheAllowlist = ['v2'];
event.waitUntil(
caches.keys().then(function(keyList) {
return Promise.all(keyList.map(function(key) {
if (cacheAllowlist.indexOf(key) === -1) {
return caches.delete(key);
}
}));
})
);
});
Specifications
Specification |
---|
Service Workers 1 # cache-storage-keys |
Browser compatibility
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