parallix/ docs
core.filter

Filter (core.filter)

Keep the items that match your conditions and drop the rest — one input, one output. Same condition system as the IF node; the difference is that IF routes every item somewhere, while Filter's non-survivors simply disappear from the run.

Parameters

ParameterTypeDefaultDescription
conditionslist of conditions[]Each condition is data_type + left + operator + right. Both sides accept {{ }} expressions, evaluated per item.
combineand | orandand: every condition must hold. or: any one is enough.
keepmatching | non_matchingmatchingWhich side survives. non_matching is a built-in "reject" — keep the failures without rewriting conditions.

The operators, per-type coercion, and the "incomparable values are just false, never a crash" guarantee are identical to the IF node — see its operator table.

Behavior

conditions  $json.n >= 10   (number)
input       {"n": 5}  {"n": 20}  {"n": 10}  {"n": 3}
output      {"n": 20}  {"n": 10}

Survivors keep their input order, their binary attachments, and a paired_item pointing at their original index — so lineage back to the source item survives the dropped rows.

Both sides can be expressions. right = {{ $json.threshold }} compares each item's n against that item's own threshold.

A fully-filtered output doesn't strand the graph. If nothing survives, downstream nodes on this branch are skipped — and a merge fed by this branch still fires on its other inputs instead of waiting forever.

Quirks & tips

  • Empty conditions follow the same vacuous-truth rule as IF: with and every item "matches" (all kept), with or none do (all dropped) — and keep: non_matching inverts both. Add a condition before trusting output.
  • A missing reference stops the node. {{ $json.nope }} on an item without that key is an expression error, not a silent drop. Use the is empty operator to test optional fields safely.
  • Dropped means gone. If you need to see the rejects (audit them, alert on them), use IF instead — its false branch is your reject stream.
  • The string data type doesn't coerce numbers (10 ≠ "10") — pick the number type for numeric comparisons, same as IF.

Related

  • IF — the two-output sibling: route instead of drop.
  • Switch — first-match routing across up to 8 named outputs.
  • Loop Over Items — process survivors in batches.