Thekeys() method of theCacheStorage interface returns aPromise that will resolve with an array containing strings corresponding to all of the namedCache objects tracked by theCacheStorage object in the order they were created.Use this method to iterate over a list of allCache objects.

You can accessCacheStorage through theWindow.caches property in windows or through theWorkerGlobalScope.caches property in workers.

Syntax

keys()

Parameters

None.

Return value

APromise that resolves with an array of theCache names inside theCacheStorage object.

Examples

In this code snippet we wait for anactivate event, and then run awaitUntil() 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 theCacheStorage object usingkeys(), then check each key to see if it is in the allowlist.If not, we delete it usingCacheStorage.delete().

this.addEventListener("activate", (event) => {  const cacheAllowlist = ["v2"];  event.waitUntil(    caches.keys().then((keyList) =>      Promise.all(        keyList.map((key) => {          if (!cacheAllowlist.includes(key)) {            return caches.delete(key);          }          return undefined;        }),      ),    ),  );});

Specifications

Browser compatibility

See also

• Using Service Workers
• Cache
• Window.caches andWorkerGlobalScope.caches