CacheStorage.has()
The has()
method of the CacheStorage
interface returns a Promise
that resolves to true
if a
Cache
object matches the cacheName
.
You can access CacheStorage
through the global
caches
property.
Syntax
caches.has(cacheName).then(function(boolean) {
// true: your cache exists!
});
Parameters
cacheName
-
A
DOMString
representing the name of theCache
object you are looking for in theCacheStorage
.
Return value
a Promise
that resolves to true
if the cache exists or
false
if not.
Examples
The following example first checks whether a cache called 'v1' exists. If so, we add a list of assets to it. If not then we run some kind of cache set-up function.
caches.has('v1').then(function(hasCache) {
if (!hasCache) {
someCacheSetupFunction();
} else {
caches.open('v1').then(function(cache) {
return cache.addAll(myAssets);
});
}
}).catch(function() {
// Handle exception here.
});
Specifications
Specification |
---|
Service Workers 1 # cache-storage-has |
Browser compatibility
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