Function

Custom JavaScript transformation function that returns an updated row with optional lineage and audit metadata.

Parameters

• function (Function Code, string, required) — JavaScript function code. See JSON Configuration for signature and examples. Default: "".

Field selection

• source — Field whose values this operation reads. Omit to apply to all fields on the row.
• target — Optional output field. When omitted, the source field is updated in place.

JSON Configuration

{
  "id": "op-function",
  "type": "transformation",
  "action": "function",
  "params": {
    "function": "({ row }) => ({ row: { ...row, total: row.price * row.quantity }, lineage: [{ outputField: 'total', inputFields: ['price', 'quantity'], usage: 'transformation' }] })"
  },
  "testInputs": [
    "Hello World",
    "MixedCase",
    "sample text",
    "already",
    "123",
    ""
  ]
}