NDJSON Parser

A simple NDJSON (Newline Delimited JSON) parser for Bun, Deno, and Web environments. It provides functions to parse NDJSON strings, streams, and a transformer for real-time processing using TransformStream.

Features

• String Parsing: Synchronously parse an NDJSON string into an array of objects.
• Stream Parsing: Read a ReadableStream (e.g., from fetch) and return a promise resolving to an array of objects.
• TransformStream Support: Use a dedicated TransformStream to process NDJSON chunks as they arrive.
• Zero Dependencies: Uses native TextDecoder and Web Stream APIs.

Installation

bun add ndjson-parser
# or
npm install ndjson-parser

Usage

1. Parse an NDJSON String

import ndjson from 'ndjson-parser';

const data = `{"id": 1, "name": "foo"}
{"id": 2, "name": "bar"}`;
const result = ndjson.parse(data);

console.log(result);
// Output: [{ id: 1, name: 'foo' }, { id: 2, name: 'bar' }]

2. Parse a ReadableStream

import ndjson from 'ndjson-parser';

const response = await fetch('https://example.com/data.ndjson');
const result = await ndjson.parseStream(response.body);

console.log(result);

3. Use with TransformStream (Real-time)

import ndjson from 'ndjson-parser';

const response = await fetch('https://example.com/data.ndjson');
const transformer = ndjson.createTransformer();

const reader = response.body
  .pipeThrough(transformer)
  .getReader();

while (true) {
  const { value, done } = await reader.read();
  if (done) break;
  console.log('Received object:', value);
}

API

parse(ndJsonString)

Synchronously parses an NDJSON string. Returns an array of objects.

parseStream(readableStream)

Reads a ReadableStream<Uint8Array> and returns a Promise that resolves to an array of parsed objects.

createTransformer()

Returns a TransformStream<Uint8Array, any> that transforms chunks of NDJSON data into parsed JavaScript objects.

License

MIT