title: Firebase Cloud Messaging (WebPush) token expiration handling
body: <p>As I found out in <a href="https://github.com/firebase/firebase-js-sdk/blob/fcb277a832058407a33456b2887a6b9990708b28/packages/messaging/src/controllers/controller-interface.ts#L129" rel="nofollow noreferrer">Firebase source</a>, every token has an expiration time of one week. And because <code>messaging().onTokenRefresh</code> is <a href="https://github.com/firebase/firebase-js-sdk/blob/fcb277a832058407a33456b2887a6b9990708b28/packages/messaging/src/controllers/window-controller.ts#L43" rel="nofollow noreferrer">not implemented now</a>, I'm assuming that there is no way of sending webpush-notifications to users that haven't been on my website with configured FCM for a week or longer.</p>
  
  <p>Or my assumption is incorrect and this expiration exists only on browser side? And tokens on the server-side of FCM aren't expiring without a call from browser to recreate token?</p>