jtcsv-codemod

jscodeshift transforms that migrate existing CSV-handling code to jtcsv.

npx jtcsv-codemod papaparse "src/**/*.{js,ts,tsx}"

Available transforms

| Transform | From | What it rewrites | |-------------|---------------|------------------------------------------------------| | papaparse | papaparse | imports, Papa.parse, Papa.unparse, option names |

More transforms (csvtojson, csv-parser) are planned — open an issue or PR with a code sample if you'd like one.

papaparse → jtcsv

Imports

- import Papa from 'papaparse';
+ import { csvToJson, jsonToCsv } from 'jtcsv';

- const Papa = require('papaparse');
+ const { csvToJson, jsonToCsv } = require('jtcsv');

Calls and option renames

- Papa.parse(csv, { header: true, dynamicTyping: true })
+ csvToJson(csv, { hasHeaders: true, parseNumbers: true })

- Papa.unparse(rows, { delimiter: ';' })
+ jsonToCsv(rows, { delimiter: ';' })

- const rows = Papa.parse(csv).data;
+ const rows = csvToJson(csv);

| Papa option | jtcsv option | Notes | |-------------------|--------------------|--------------------------------------| | header | hasHeaders | | | dynamicTyping | parseNumbers | | | delimiter | delimiter | unchanged | | newline | newline | unchanged | | quoteChar | quoteChar | unchanged | | escapeChar | escapeChar | unchanged | | comments | comments | unchanged | | skipEmptyLines | skipEmptyLines | unchanged |

Dropped options

These have no jtcsv equivalent and are stripped, with a // TODO(jtcsv-codemod): … comment left at the call site so you can review:

worker, download, fastMode, beforeFirstChunk, transformHeader, preview, encoding, chunk, step, complete, error.

If you used step/complete for streaming, switch to:

import { createCsvToJsonStream } from 'jtcsv';
import { createReadStream } from 'fs';

await createReadStream('big.csv')
  .pipe(createCsvToJsonStream({ hasHeaders: true, parseNumbers: true }))
  .on('data', (row) => { /* per-row logic that used to live in step() */ });

CLI flags

The CLI is a thin wrapper around jscodeshift. Anything after -- is passed straight through:

# dry-run (no writes, prints diff)
npx jtcsv-codemod papaparse src/ -- --dry --print

# only .ts and .tsx files
npx jtcsv-codemod papaparse src/ -- --extensions=ts,tsx

Limitations

• Streaming patterns (Papa.parse(file, { step })) are flagged but not rewritten end-to-end — the manual switch is short, see above.
• Web Workers (Papa.parse(file, { worker: true })) require deciding between jtcsv/web-workers and Node worker_threads; we don't guess.
• Comment placement varies slightly by jscodeshift version; review the diff before committing.

Contributing

Source: transforms/papaparse-to-jtcsv.js. Tests: __tests__/papaparse-to-jtcsv.test.js (jscodeshift's applyTransform helper).

PRs welcome.