The parameter passed into the oninstall
handler, the InstallEvent
interface represents an install action that is dispatched on the ServiceWorkerGlobalScope
of a ServiceWorker
. As a child of ExtendableEvent
, it ensures that functional events such as FetchEvent
are not dispatched during installation.
This interface inherits from the ExtendableEvent
interface.
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Constructor
InstallEvent.InstallEvent()
- Creates a new
InstallEvent
object.
Properties
Inherits properties from its ancestor, Event
.
InstallEvent.activeWorker
Read only- Returns the
ServiceWorker
that is currently controlling the page.
Methods
Inherits methods from its parent, ExtendableEvent
.
Examples
This code snippet is from the service worker prefetch sample (see prefetch running live.) The code calls ExtendableEvent.waitUntil()
in ServiceWorkerGlobalScope.oninstall
and delays treating the ServiceWorkerRegistration.installing
worker as installed until the passed promise resolves successfully. The promise resolves when all resources have been fetched and cached, or when any exception occurs.
The code snippet also shows a best practice for versioning caches used by the service worker. Although this example has only one cache, you can use this approach for multiple caches. The code maps a shorthand identifier for a cache to a specific, versioned cache name.
Note: Logging statements are visible in Google Chrome via the "Inspect" interface for the relevant service worker accessed via chrome://serviceworker-internals.
var CACHE_VERSION = 1; var CURRENT_CACHES = { prefetch: 'prefetch-cache-v' + CACHE_VERSION }; self.addEventListener('install', function(event) { var urlsToPrefetch = [ './static/pre_fetched.txt', './static/pre_fetched.html', 'https://www.chromium.org/_/rsrc/1302286216006/config/customLogo.gif' ]; console.log('Handling install event. Resources to pre-fetch:', urlsToPrefetch); event.waitUntil( caches.open(CURRENT_CACHES['prefetch']).then(function(cache) { return cache.addAll(urlsToPrefetch.map(function(urlToPrefetch) { return new Request(urlToPrefetch, {mode: 'no-cors'}); })).then(function() { console.log('All resources have been fetched and cached.'); }); }).catch(function(error) { console.error('Pre-fetching failed:', error); }) ); });
Specifications
Specification | Status | Comment |
---|---|---|
Service Workers | Working Draft | As of May 2015, the install event is an instance of ExtendableEvent rather than a child of it. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
InstallEvent | Chrome Full support 40 | Edge Full support ≤79 | Firefox
Full support
44
| IE No support No | Opera Full support 27 | Safari No support No | WebView Android Full support 40 | Chrome Android Full support 40 | Firefox Android Full support 44 | Opera Android Full support 27 | Safari iOS No support No | Samsung Internet Android Full support 4.0 |
InstallEvent() constructor | Chrome Full support 40 | Edge Full support ≤79 | Firefox
Full support
44
| IE No support No | Opera Full support 27 | Safari No support No | WebView Android Full support 40 | Chrome Android Full support 40 | Firefox Android Full support 44 | Opera Android Full support 27 | Safari iOS No support No | Samsung Internet Android Full support 4.0 |
activeWorker | Chrome Full support 40 | Edge Full support ≤79 | Firefox
Full support
44
| IE No support No | Opera Full support 27 | Safari No support No | WebView Android Full support 40 | Chrome Android Full support 40 | Firefox Android Full support 44 | Opera Android Full support 27 | Safari iOS No support No | Samsung Internet Android Full support 4.0 |
Legend
- Full support
- Full support
- No support
- No support
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.
- See implementation notes.
- See implementation notes.