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Auto reconnect - typescript sdk - #5927

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alessandro/refuse-takeover-for-same-session-and-teardownfrom
alessandro/auto-reconnect-typescript-sdk
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Auto reconnect - typescript sdk#5927
aasoni wants to merge 2 commits into
alessandro/refuse-takeover-for-same-session-and-teardownfrom
alessandro/auto-reconnect-typescript-sdk

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@aasoni

@aasoni aasoni commented Sep 11, 2026

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Description of Changes

TypeScript SDK: automatic reconnection

Builds reconnection into DbConnection itself, so the connection object, the client cache, table handles and registered callbacks all stay usable across a reconnect and applications manage no replacement objects.

withAutomaticReconnect() enables this. Losing an established connection fires onDisconnect, each failed attempt fires onConnectError, and both now report the number of and delay before the next attempt, or undefined when the SDK will not retry. Retries are unlimited with exponential backoff (1s base, 30s cap, 0.5 jitter), stopping only on disconnect(), a failed initial connection, or a reconnect under a different identity.

Each reconnect is a new connection which fires onConnect again. Live subscriptions are replayed in one SubscribeBatch under fresh query set ids, and the results are reconciled against the stale cache with synthesized deletes, so rows unchanged across the outage produce no callbacks and changed rows produce ordinary update or delete callbacks.

A stable client-generated session_id is sent on every connection so the server can teardown the previous connection if still open (idle timeout didn't fire yet) before accepting a new one for the same session.

The token the server issued is saved and reused, keeping the identity stable for anonymous clients; withTokenProvider() supplies a fresh token when the saved one is close to expiring or was rejected.

Calls made while disconnected fail fast with DisconnectedError, and calls in flight when the connection dropped settle with UnknownCallResultError, since they may or may not have run.

Behavior is unchanged for connections which do not opt in.

API and ABI breaking changes

No

Rollback safety impact

Requires #5877 to have been deployed in a previous release

Expected complexity level and risk

3 - Change is limited to the typescript SDK and is opt in only (withAutomaticReconnect and withTokenProvider are the new APIs). Change is large but not overly complex.

Testing

Test app that fakes dropping connections and reconnecting and uses spacetime's own token provider to test token with expiry claim in the reconnect scenario as well.

@aasoni
aasoni changed the base branch from master to alessandro/auto-reconnect-server-side September 11, 2026 13:31
@aasoni aasoni changed the title Alessandro/auto reconnect typescript sdk Auto reconnect - typescript sdk Sep 11, 2026
@aasoni
aasoni changed the base branch from alessandro/auto-reconnect-server-side to alessandro/refuse-takeover-for-same-session-and-teardown September 11, 2026 13:34
@aasoni
aasoni force-pushed the alessandro/auto-reconnect-typescript-sdk branch from c0eecbf to 812ee9b Compare September 11, 2026 13:41
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