ServiceWorkerRegistration: index property

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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 index read-only property of the ServiceWorkerRegistration interface returns a reference to the ContentIndex interface, which allows for indexing of offline content.


A ContentIndex object.


You can access the property from either your main script or the registered service worker.

Here is an example from the main script:

// reference registration
const registration = await navigator.serviceWorker.ready;

// feature detection
if ("index" in registration) {
  // Content Index API functionality
  const contentIndex = registration.index;

From the service worker:

// service worker script

const contentIndex = self.registration.index;


Content Index
# dom-serviceworkerregistration-index

Browser compatibility

BCD tables only load in the browser

See also