The getState()
method of the NavigationPreloadManager
interface returns a Promise
that resolves to an object with properties that indicate whether preload is enabled and what value will be sent in the Service-Worker-Navigation-Preload
HTTP header.
NavigationPreloadManager.getState()
Syntax
getState()
Return value
A Promise
that resolves with an object that has the following properties:
-
enabled
-
true
if preloading is enabled, andfalse
otherwise. -
headerValue
-
A string containing the value that will be sent in the
Service-Worker-Navigation-Preload
HTTP header following a preloadingfetch()
. This defaults totrue
unless the value was changed usingNavigationPreloadManager.setHeaderValue()
.
Exceptions
-
InvalidStateError
DOMException
-
There is no active worker associated with the registration to which this
NavigationPreloadManager
belongs.
Examples
The code below shows a request for the current state, made once the service worker is ready.
navigator.serviceWorker.ready .then((registration) => { return registration.navigationPreload.getState(); }) .then((state) => { console.log(state.enabled); // boolean console.log(state.headerValue); // string }) .catch(e => console.error("NavigationPreloadManager not supported: " + e.message));
Specifications
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
getState |
59
|
18
|
97
preview
|
No
|
46
|
15.4
|
59
|
59
|
No
|
43
|
15.4
|
7.0
|
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https://developer.mozilla.org/en-US/docs/Web/API/NavigationPreloadManager/getState