NavigationPreloadManager: enable() method

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 available in Web Workers.

The enable() method of the NavigationPreloadManager interface is used to enable preloading of resources managed by the service worker. It returns a promise that resolves with undefined.

The method should be called in the service worker's activate event handler, which ensures it is called before any fetch event handler can fire.

Syntax

enable()

Parameters

None.

Return value

A Promise that resolves with undefined.

Exceptions

InvalidStateError DOMException: There is no active worker associated with the registration to which this NavigationPreloadManager belongs.

Examples

The code below shows how to enable preloading, after first using ServiceWorkerRegistration.navigationPreload to test that it is supported.

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

Specifications

Specification
Service Workers # dom-navigationpreloadmanager-enable

Browser compatibility

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