The ServiceWorkerGlobalScope
interface of the Service Worker API represents the global execution context of a service worker.
Developers should keep in mind that the ServiceWorker state is not persisted across the termination/restart cycle, so each event handler should assume it's being invoked with a bare, default global state.
Once successfully registered, a service worker can and will be terminated when idle to conserve memory and processor power. An active service worker is automatically restarted to respond to events, such as ServiceWorkerGlobalScope.onfetch
or ServiceWorkerGlobalScope.onmessage
.
Additionally, synchronous requests are not allowed from within a service worker — only asynchronous requests, like those initiated via the fetch()
method, can be used.
This interface inherits from the WorkerGlobalScope
interface, and its parent EventTarget
.
ServiceWorkerGlobalScope.caches
Read only
Contains the CacheStorage
object associated with the service worker.
ServiceWorkerGlobalScope.clients
Read only
Contains the Clients
object associated with the service worker.
ServiceWorkerGlobalScope.registration
Read only
Contains the ServiceWorkerRegistration
object that represents the service worker's registration.
activate
Occurs when a ServiceWorkerRegistration
acquires a new ServiceWorkerRegistration.active
worker. Also available via the ServiceWorkerGlobalScope.onactivate
property.
contentdelete
Occurs when an item is removed from the Content Index
. Also available via the ServiceWorkerGlobalScope.oncontentdelete
property.
fetch
Occurs when a fetch()
is called. Also available via the ServiceWorkerGlobalScope.onfetch
property.
install
Occurs when a ServiceWorkerRegistration
acquires a new ServiceWorkerRegistration.installing
worker. Also available via the ServiceWorkerGlobalScope.oninstall
property.
message
Occurs when incoming messages are received. Controlled pages can use the MessagePort.postMessage()
method to send messages to service workers. The service worker can optionally send a response back via the MessagePort
exposed in event.data.port
, corresponding to the controlled page. Also available via the ServiceWorkerGlobalScope.onmessage
property.
notificationclick
Occurs when a user clicks on a displayed notification. Also available via the ServiceWorkerGlobalScope.onnotificationclick
property.
notificationclose
Occurs — when a user closes a displayed notification. Also available via the ServiceWorkerGlobalScope.onnotificationclose
property.
sync
Triggered when a call to SyncManager.register
is made from a service worker client page. The attempt to sync is made either immediately if the network is available or as soon as the network becomes available. Also available via the ServiceWorkerGlobalScope.onsync
property.
periodicsync
Occurs at periodic intervals, which were specified when registering a PeriodicSyncManager
. Also available via the ServiceWorkerGlobalScope.onperiodicsync
property.
push
Occurs when a server push notification is received. Also available via the ServiceWorkerGlobalScope.onpush
property.
pushsubscriptionchange
Occurs when a push subscription has been invalidated, or is about to be invalidated (e.g. when a push service sets an expiration time). Also available via the ServiceWorkerGlobalScope.onpushsubscriptionchange
property.
ServiceWorkerGlobalScope.skipWaiting()
Allows the current service worker registration to progress from waiting to active state while service worker clients are using it.
ServiceWorkerGlobalScope
implements WorkerGlobalScope
. Therefore it also has the following property available to it:
fetch()
Starts the process of fetching a resource. This returns a promise that resolves to the Response
object representing the response to your request. This algorithm is the entry point for the fetch handling handed to the service worker context.
This code snippet is from the service worker prefetch sample (see prefetch example live.) The ServiceWorkerGlobalScope.onfetch
event handler listens for the fetch
event. When fired, the code returns a promise that resolves to the first matching request in the Cache
object. If no match is found, the code fetches a response from the network.
The code also handles exceptions thrown from the fetch()
operation. Note that an HTTP error response (e.g., 404) will not trigger an exception. It will return a normal response object that has the appropriate error code set.
self.addEventListener('fetch', function(event) { console.log('Handling fetch event for', event.request.url); event.respondWith( caches.match(event.request).then(function(response) { if (response) { console.log('Found response in cache:', response); return response; } console.log('No response found in cache. About to fetch from network...'); return fetch(event.request).then(function(response) { console.log('Response from network is:', response); return response; }, function(error) { console.error('Fetching failed:', error); throw error; }); }) ); });
Specification |
---|
Service Workers 1 # serviceworkerglobalscope-interface |
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
ServiceWorkerGlobalScope |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
activate_event |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
clients |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
cookieStore |
87 |
87 |
No |
No |
73 |
No |
87 |
87 |
No |
No |
No |
14.0 |
install_event |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
message_event |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
notificationclick_event |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
No |
No |
40 |
44 |
27 |
No |
4.0 |
onabortpayment |
70 |
79 |
No |
No |
? |
No |
No |
70 |
No |
? |
No |
No |
onactivate |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
onbackgroundfetchabort |
74 |
79 |
No |
No |
62 |
No |
No |
74 |
No |
53 |
No |
11.0 |
onbackgroundfetchclick |
74 |
79 |
No |
No |
62 |
No |
No |
74 |
No |
53 |
No |
11.0 |
onbackgroundfetchfail |
74 |
79 |
No |
No |
62 |
No |
No |
74 |
No |
53 |
No |
11.0 |
onbackgroundfetchsuccess |
74 |
79 |
No |
No |
62 |
No |
No |
74 |
No |
53 |
No |
11.0 |
oncanmakepayment |
70 |
79 |
No |
No |
57 |
No |
No |
70 |
No |
49 |
No |
10.0 |
oncontentdelete |
No |
No |
No |
No |
No |
No |
84 |
84 |
No |
60 |
No |
14.0 |
oncookiechange |
87 |
87 |
No |
No |
73 |
No |
87 |
87 |
No |
No |
No |
14.0 |
onfetch |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
oninstall |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
onmessage |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
11.1 |
40 |
40 |
44 |
24 |
11.3 |
4.0 |
onmessageerror |
81 |
81 |
65 |
No |
68 |
11.1
Although the
onmessageerror property is supported, the messageerror event is never fired. See bug 171216. |
81 |
81 |
65 |
58 |
11.3
Although the
onmessageerror property is supported, the messageerror event is never fired. See bug 171216. |
13.0 |
onnotificationclick |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
No |
40 |
40 |
44 |
24 |
No |
4.0 |
onnotificationclose |
50 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
34 |
No |
50 |
50 |
44 |
34 |
No |
5.0 |
onpaymentrequest |
70 |
79 |
No |
No |
? |
No |
No |
70 |
No |
? |
No |
No |
onperiodicsync |
80 |
80 |
No |
No |
67 |
No |
No |
80 |
No |
57 |
No |
13.0 |
onpush |
42 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
26 |
No |
42 |
42 |
44 |
26 |
No |
4.0 |
onpushsubscriptionchange |
No |
17-79 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
No |
No |
No |
No |
44 |
No |
No |
No |
onsync |
49 |
79 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
No |
49 |
49 |
44 |
24 |
No |
5.0 |
periodicsync_event |
80 |
80 |
No |
No |
67 |
No |
No |
80 |
No |
57 |
No |
13.0 |
push_event |
40 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
24 |
No |
40 |
40 |
44 |
24 |
No |
4.0 |
pushsubscriptionchange_event |
No |
17-79 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
No |
No |
No |
No |
44 |
No |
No |
No |
registration |
42 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
26 |
11.1 |
42 |
42 |
44 |
26 |
11.3 |
4.0 |
serviceWorker |
79 |
79 |
No |
No |
66 |
No |
79 |
79 |
No |
57 |
No |
12.0 |
skipWaiting |
41 |
17 |
44
Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
|
No |
25 |
11.1 |
41 |
41 |
44 |
25 |
11.3 |
4.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerGlobalScope