What are the different Socket.io disconnect reasons?
io server disconnect (server kicked the client, no auto-reconnect), io client disconnect (client explicitly disconnected, no auto-reconnect), ping timeout (server didn't respond, auto-reconnect), transport close (connection closed, auto-reconnect), transport error (connection error, auto-reconnect).
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More FAQs in Socket.io Error Handling and Reconnection Reliable Real-Time Communication
Yes, by default. Socket.io reconnects with configurable options: reconnectionAttempts (max attempts), reconnectionDelay (initial delay), reconnectionDelayMax (max delay), and randomizationFactor. Reconnection uses exponential backoff. Some disconnect reasons (io server disconnect, io client disconnect) don't trigger reconnection.
Store active chat target user IDs in a client-side array. On the 'connect' event (which fires on reconnection too), re-emit 'join:chat' for each stored target. The server rejoins the socket to the room. This restores room membership after the new socket ID is assigned.
Acknowledgments are callback functions passed as the last argument to socket.emit(). The server calls the callback with a response, confirming the event was received and processed. Use them for important events like message sending: socket.emit('message:send', data, (response) => { ... }).
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