Web/API/NavigationPreloadManager

The NavigationPreloadManager interface of the the Service Worker API provides methods for managing the preloading of resources with a service worker.

Methods

NavigationPreloadManager.enable()

Enables navigation preloading and returns a Promise that resolves.

NavigationPreloadManager.disable()

Disables navigation preloading and returns a Promise that resolves.

NavigationPreloadManager.setHeaderValue()

Sets the value of the Service-Worker-Navigation-Preload header and returns an empty Promise.

NavigationPreloadManager.getState()

Returns a Promise that resolves to an object with properties indicating whether preload is enabled and the contents of the Service-Worker-Navigation-Preload.

Examples

Feature Detecting and Enabling Navigation Preloading 

addEventListener('activate', event => {
  event.waitUntil(async function() {
    if (self.registration.navigationPreload) {
      // Enable navigation preloads!
      await self.registration.navigationPreload.enable();
    }
  }());
});

Using a Preloaded Response

The following example shows the implementation of a fetch event that uses a preloaded response. 

addEventListener('fetch', event => {
  event.respondWith(async function() {
    // Respond from the cache if we can
    const cachedResponse = await caches.match(event.request);
    if (cachedResponse) return cachedResponse;

    // Else, use the preloaded response, if it's there
    const response = await event.preloadResponse;
    if (response) return response;

    // Else try the network.
    return fetch(event.request);
  }());
});

Specifications

Specification	Status	Comment
Service WorkersThe definition of 'NavigationPreloadManager' in that specification.	Working Draft	Initial definition.

Browser Compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
NavigationPreloadManager Experimental'	Chrome Full support 62	Edge Full support 18	Firefox No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	IE No support No	Opera Full support 49	Safari No support No	WebView Android Full support 62	Chrome Android Full support 62	Firefox Android No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	Opera Android Full support 46	Safari iOS No support No	Samsung Internet Android Full support 8.0
disable Experimental'	Chrome Full support 62	Edge Full support 18	Firefox No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	IE No support No	Opera Full support 49	Safari No support No	WebView Android Full support 62	Chrome Android Full support 62	Firefox Android No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	Opera Android Full support 46	Safari iOS No support No	Samsung Internet Android Full support 8.0
enable Experimental'	Chrome Full support 62	Edge Full support 18	Firefox No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	IE No support No	Opera Full support 49	Safari No support No	WebView Android Full support 62	Chrome Android Full support 62	Firefox Android No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	Opera Android Full support 46	Safari iOS No support No	Samsung Internet Android Full support 8.0
getState Experimental'	Chrome Full support 62	Edge Full support 18	Firefox No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	IE No support No	Opera Full support 49	Safari No support No	WebView Android Full support 62	Chrome Android Full support 62	Firefox Android No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	Opera Android Full support 46	Safari iOS No support No	Samsung Internet Android Full support 8.0
setHeaderValue Experimental'	Chrome Full support 62	Edge Full support 18	Firefox No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	IE No support No	Opera Full support 49	Safari No support No	WebView Android Full support 62	Chrome Android Full support 62	Firefox Android No support No Notes' No support No Notes' Notes' Implementation tracked in bug 1290958	Opera Android Full support 46	Safari iOS No support No	Samsung Internet Android Full support 8.0

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.

NavigationPreloadManager by Mozilla Contributors is licensed under CC-BY-SA 2.5.