CacheStorage: has() method
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Note: This feature is available in Web Workers.
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 Window.caches property in windows or through the WorkerGlobalScope.caches property in workers.
Syntax
has(cacheName) Parameters
cacheName-
A string representing the name of the
Cacheobject 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((hasCache) => { if (!hasCache) { someCacheSetupFunction(); } else { caches.open("v1").then((cache) => cache.addAll(myAssets)); } }) .catch(() => { // Handle exception here. }); Specifications
| Specification |
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| Service Workers # cache-storage-has |