FetchEvent: resultingClientId property

The resultingClientId read-only property of the FetchEvent interface is the id of the client that replaces the previous client during a page navigation.

For example, when navigating from page A to page B resultingClientId is the ID of the client associated with page B.

If the fetch request is a subresource request or the request's destination is report, resultingClientId will be an empty string.

self.addEventListener("fetch", (event) => {
  console.log(event.resultingClientId);
});