Class: ExpirationPlugin

workbox-expiration.ExpirationPlugin

class static

Version 6.2.0

This plugin can be used in a workbox-strategy to regularly enforce a limit on the age and / or the number of cached requests.

It can only be used with workbox-strategy instances that have a custom cacheName property set. In other words, it can't be used to expire entries in strategy that uses the default runtime cache name.

Whenever a cached request is used or updated, this plugin will look at the associated cache and remove any old or extra requests.

When using maxAgeSeconds, requests may be used once after expiring because the expiration clean up will not have occurred until after the cached request has been used. If the request has a "Date" header, then a light weight expiration check is performed and the request will not be used immediately.

When using maxEntries, the entry least-recently requested will be removed from the cache first.

Constructor

ExpirationPlugin

new ExpirationPlugin(config)

Parameter

config

ExpirationPluginOptions

Values in config have the following properties:

Parameter
maxEntries	Optional number The maximum number of entries to cache. Entries used the least will be removed as the maximum is reached.
maxAgeSeconds	Optional number The maximum age of an entry before it's treated as stale and removed.
matchOptions	Optional Object The `CacheQueryOptions` that will be used when calling `delete()` on the cache.
purgeOnQuotaError	Optional boolean Whether to opt this cache in to automatic deletion if the available storage quota has been exceeded.

Method

deleteCacheAndMetadata

async

deleteCacheAndMetadata()

This is a helper method that performs two operations:

Deletes all the underlying Cache instances associated with this plugin instance, by calling caches.delete() on your behalf.
Deletes the metadata from IndexedDB used to keep track of expiration details for each Cache instance.

When using cache expiration, calling this method is preferable to calling caches.delete() directly, since this will ensure that the IndexedDB metadata is also cleanly removed and open IndexedDB instances are deleted.

Note that if you're not using cache expiration for a given cache, calling caches.delete() and passing in the cache's name should be sufficient. There is no Workbox-specific method needed for cleanup in that case.