The getRegistration() method of the ServiceWorkerContainer interface gets a ServiceWorkerRegistration object whose scope URL matches the provided client URL. The method returns a Promise that resolves to a ServiceWorkerRegistration or undefined.
getRegistration()
getRegistration(clientURL)
A Promise that resolves to a ServiceWorkerRegistration object or undefined.
navigator.serviceWorker.getRegistration("/app").then((registration) => {
if (registration) {
document.querySelector("#status").textContent =
"ServiceWorkerRegistration found.";
}
});