Fold Source Fields Before Merge: Self-Contained Items Without pairedItem Expressions

How it works

1. 1.Manual trigger emits an empty item into both branch paths
2. 2.Two Code nodes generate demo items shaped {order, payer}, one with an invalid payer value
3. 3.Fold nodes copy order.id, amount, currency, payer.name, payer.method into _a_* and _b_* with type normalisation
4. 4.Each fold node computes _fold_missing, _fold_complete and the _src branch tag
5. 5.Set nodes add _fold_version with includeOtherFields enabled
6. 6.Merge in append mode combines both branches into one stream
7. 7.IF checks _fold_complete with strict type validation: true to the self check, false to the NoOp quarantine
8. 8.A second Merge rejoins both routes and the final Code node flattens fields, emitting status and missing_fields per item

Use cases

• Stabilising flows where $('NodeName').item broke after a merge node
• Unifying order and payment records from two different sources
• Flagging records with missing fields separately from valid ones
• Auditing merged data quality before export

Requirements

• n8n 2.46.4 or a build with equivalent merge behaviour
• A decided list of fields needed later before editing the fold nodes
• Replace the two sample Code nodes with real sources using the same {order, payer} schema
• Never use $('NodeName').item after the merge node

Setup and testing in n8n

1. Import the JSON and click Execute Workflow
2. Confirm Build Final Records outputs four records: three complete and one quarantined
3. Confirm ORD-1003 has status=quarantined with missing_fields containing _b_payerName and _b_payerMethod
4. Swap the branch wiring between merge inputs 0 and 1 and confirm the same record set
5. Set one sample array to empty and confirm the run finishes without error

Service Value

Ready-made workflow template for automation delivery and service execution.