Migrating Nango Deletion Detection

Do this

1. Find legacy usage:
   • deleteRecordsFromPreviousExecutions(
   • trackDeletes: / track_deletes
2. For each sync + model that needs automatic deletion detection:
   • Add await nango.trackDeletesStart('ModelName') at the start of exec (before fetching/saving).
   • Replace await nango.deleteRecordsFromPreviousExecutions('ModelName') with await nango.trackDeletesEnd('ModelName').
   • Keep trackDeletesEnd after all batchSave/batchUpdate/batchDelete calls.
3. Safety:
   • Only call trackDeletesEnd if the full dataset was fetched + saved between trackDeletesStart and trackDeletesEnd (otherwise you can cause false deletions).
   • Prefer letting exceptions bubble. If you catch, re-throw when data is incomplete.

Checkpointed full refresh (multi-execution)

Full refresh syncs need a pagination checkpoint (page/cursor/offset) in addition to delete tracking. Nango syncs run inside a time-limited execution window; without a checkpoint, a run that does not finish in that window restarts from page 1 next time, wasting compute re-fetching the same early pages and never reaching the rest of the dataset.