ServiceWorkerGlobalScope: activate event
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 only available in Service Workers.
The activate event of the ServiceWorkerGlobalScope interface is fired when a ServiceWorkerRegistration acquires a new ServiceWorkerRegistration.active worker.
This event is not cancelable and does not bubble.
Syntax
Use the event name in methods like addEventListener(), or set an event handler property.
addEventListener("activate", (event) => { })
onactivate = (event) => { }
Event type
An ExtendableEvent. Inherits from Event.
Event properties
Doesn't implement any specific properties, but inherits properties from its parent, Event.
Examples
The following snippet shows how you could use an activate event handler to upgrade a cache.
self.addEventListener("activate", (event) => {
const cacheAllowlist = ["v2"];
event.waitUntil(
caches.keys().then((cacheNames) =>
Promise.all(
cacheNames.map((cacheName) => {
if (!cacheAllowlist.includes(cacheName)) {
return caches.delete(cacheName);
}
return undefined;
}),
),
),
);
});
You can also set up the event handler using the onactivate property:
self.onactivate = (event) => {
// …
};
Specifications
| Specification |
|---|
| Service Workers # service-worker-global-scope-activate-event |
| Service Workers # dom-serviceworkerglobalscope-onactivate |
Browser compatibility
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