chromium/chrome/test/data/service_worker/create_service_worker.html

<html>
<title>create service worker</title>
<body>this page is for registering a service worker</body>
<script>
// Copy of //content/test/data/service_worker/create_service_worker.html.

// Simulates navigator.serviceWorker.ready, which can't be used since this
// document may not be in-scope.
async function whenReady(registration) {
  if (registration.active)
    return;
  // If there's no .active, .waiting will activate before .installing.
  const nextActiveWorker = registration.waiting || registration.installing;
  return new Promise((resolve, reject) => {
    nextActiveWorker.addEventListener('statechange', event => {
      if (nextActiveWorker.state == 'activated')
        resolve();
      if (nextActiveWorker.state == 'redundant')
        reject('worker became redundant');
    });
  });
}

async function register(worker_url, scope, type) {
  try {
    const init = {};
    if (scope)
      init['scope'] = scope;
    if (type)
      init['type'] = type;
    const registration =
        await navigator.serviceWorker.register(worker_url, init);
    await whenReady(registration);
    return 'DONE';
  } catch (error) {
    return `${error}`;
  }
}

async function update(scope) {
  try {
    const registration =
        scope ?
            await navigator.serviceWorker.getRegistration(scope) :
            await navigator.serviceWorker.ready;
    await registration.update();
    return 'DONE';
  } catch (error) {
    return `${error}`;
  }
}
</script>
</html>