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)

• Call

  trackDeletesStart('ModelName')

  at the beginning of each execution in the refresh window (it is safe/idempotent while the window is open).
• Call

  trackDeletesEnd('ModelName')

  only in the execution that finishes saving the full dataset.

Tests

• Re-record mocks after code changes:

  • nango dryrun <sync-name> <connection-id> --validate -e dev --no-interactive --auto-confirm

  • nango dryrun <sync-name> <connection-id> --save -e dev --no-interactive --auto-confirm

  • nango generate:tests && npm test

• Never hand-edit

  *.test.json

  .

Before/after

// Before
for await (const page of nango.paginate(cfg)) {
    await nango.batchSave(page, 'Ticket');
}
await nango.deleteRecordsFromPreviousExecutions('Ticket');

// After
await nango.trackDeletesStart('Ticket');

for await (const page of nango.paginate(cfg)) {
    await nango.batchSave(page, 'Ticket');
}

await nango.trackDeletesEnd('Ticket');