rxjs-notification.js

import { notificationObservable } from 'services/notificationService'
const Notification = () => {
 const [notification, setNotification] = useState('')
 useEffect(() => {
   // called when component first mounts
   const subscription = notificationObservable.subscribe((value) => {
     // re-render with new value
     setNotification(value)
   })
   return () => {
     // called when component unmounts (this is important)
     subscription.unsubscribe()
   }
 }, [])
 
 return <div>{notification}</div>
}