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.
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.
js
has(cacheName)
cacheName
A string representing the name of the Cache
object you are looking for in the CacheStorage
.
a Promise
that resolves to true
if the cache exists or false
if not.
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.
js
caches .has("v1") .then((hasCache) => { if (!hasCache) { someCacheSetupFunction(); } else { caches.open("v1").then((cache) => cache.addAll(myAssets)); } }) .catch(() => { // Handle exception here. });
Specification |
---|
Service Workers # cache-storage-has |
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
has |
40 | 16 | 41 | No | 27 | 11.1 | 40 | 40 | 41 | 27 | 11.3 | 4.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/CacheStorage/has