@uiw/react-use-online/esm/index.js

useOnline is a tiny, zero-dependency hook for responding to online/offline changes.

import { useSyncExternalStore } from 'react';
function getSnapshot() {
  return navigator.onLine;
}
function getServerSnapshot() {
  return true;
}
function subscribe(callback) {
  window.addEventListener('online', callback);
  window.addEventListener('offline', callback);
  return () => {
    window.removeEventListener('online', callback);
    window.removeEventListener('offline', callback);
  };
}
export function useOnline() {
  return useSyncExternalStore(subscribe, getSnapshot, getServerSnapshot);
}