files/en-us/web/api/serviceworkerregistration/update/index.md
{{APIRef("Service Workers API")}}{{SecureContext_Header}} {{AvailableInWorkers}}
The update() method of the
{{domxref("ServiceWorkerRegistration")}} interface attempts to update the service
worker. It fetches the worker's script URL, and if the new worker is not byte-by-byte
identical to the current worker, it installs the new worker. The fetch of the worker
bypasses any browser caches if the previous fetch occurred over 24 hours ago.
update()
None.
A {{jsxref("Promise")}} that resolves with a {{domxref("ServiceWorkerRegistration")}} object.
The following simple example registers a service worker example then adds an event handler to a button so you can explicitly update the service worker whenever desired:
if ("serviceWorker" in navigator) {
navigator.serviceWorker
.register("/sw.js", { scope: "/" })
.then((registration) => {
// registration worked
console.log("Registration succeeded.");
button.onclick = () => {
registration.update();
};
})
.catch((error) => {
// registration failed
console.error(`Registration failed with ${error}`);
});
}
{{Specifications}}
{{Compat}}