Network loss, reconnection and recoverable uploads.
The engine listens to the browser's online and offline events (once mounted, the
React hooks do this for you).
When the browser goes offline:
- No new uploads start; queued items wait.
- Uploads that fail with a network error are paused with
pauseReason: "offline"instead of failing, and the attempt doesn't count against the retry budget. UploadStatusshows “Waiting for network”.
When it comes back online, offline-paused items are re-queued automatically. Resumable adapters continue from their last part; others restart.
uploader.on("online", ({ online }) => console.log(online ? "back online" : "offline"))
const online = useNetworkStatus()What “online” means
navigator.onLine only says a network interface is up, not that your server is
reachable. That's why every network failure is also retried with exponential backoff,
online or not.
Testing it
In Chrome DevTools, set Network → Offline during an upload. With a resumable adapter (try the pause/resume example), go back online and watch it continue.