option.on_record.alter.js

import assert from 'node:assert';
import { parse } from 'csv-parse';

parse(`
a.1,a.2,a.3
b.1,b.2,b.3
`.trim(), {
  on_record: (record, {lines}) =>
    [lines, record[2], record[0]]
}, function(err, records){
  assert.deepStrictEqual(
    records, [
      [1, 'a.3', 'a.1'],
      [2, 'b.3', 'b.1']
    ]
  );
});