qrcode-core

@playwright-labs/qrcode-core

QR code encode/decode primitives for Node.js — one encoder with 8 output formats, one decoder that accepts anything image-like.

What this package provides

@playwright-labs/qrcode-core is the shared foundation used by @playwright-labs/fixture-qrcode. It can also be used standalone in any Node.js project that needs:

• QRCodeEncoder — builds QR codes from a string or composed segments
• QRCodeDecoder — decodes QR codes from buffers, streams, files, base64 strings, or raw pixel data
• SegmentArray — fluent builder for mixed-mode QR segments (numeric/alphanumeric/byte)

Installation

pnpm add @playwright-labs/qrcode-core

Quick start

import { QRCodeEncoder, QRCodeDecoder } from '@playwright-labs/qrcode-core';

const png = await new QRCodeEncoder({ type: 'buffer' }).encode('hello world');
const decoded = await new QRCodeDecoder().decode(png as Buffer);

console.log(decoded?.data); // 'hello world'

QRCodeEncoder

Output format is configured via constructor options:

type	encode() resolves with
base64-prefix (default)	data URL — data:image/png;base64,...
base64url	raw base64 payload, no prefix
svg	SVG markup string
utf8	text-art string
terminal	terminal-friendly string; supports small, margin, scale, width, color
buffer	PNG Buffer
file	writes PNG to path, resolves with the path
stream	pipes PNG into writable, resolves with '' on finish

// file
await new QRCodeEncoder({ type: 'file', path: 'qr.png' }).encode('hello');

// stream
import { PassThrough } from 'node:stream';
const writable = new PassThrough();
await new QRCodeEncoder({ type: 'stream', writable }).encode('hello');

// terminal
console.log(await new QRCodeEncoder({ type: 'terminal', small: true }).encode('hello'));

Segments

Mixed-mode segments produce smaller QR codes than plain strings:

const encoder = new QRCodeEncoder()
  .addStringSegment('order:')
  .addNumericSegment(12345)
  .addAlphanumericSegment('ABC-42')
  .addByteSegment(Buffer.from([0x01, 0x02]));

const dataUrl = await encoder.encode(); // no argument — segments are used

Rules:

• encode(string) or segments — using both throws TypeError
• neither — throws TypeError

SegmentArray is also exported for standalone composition — build segments separately, hand them to any encoder:

import { SegmentArray, QRCodeEncoder } from '@playwright-labs/qrcode-core';

const segments = new SegmentArray()
  .addStringSegment('user:')
  .addNumericSegment(7)
  .addByteSegment(Buffer.from([0x01, 0x02]));

const path = await new QRCodeEncoder({ type: 'file', path: 'segments-qr.png' })
  .addSegments(...segments)
  .encode();

Segment methods (same set on SegmentArray and QRCodeEncoder):

Method	QR mode
addStringSegment(str)	auto
addNumericSegment(123)	numeric
addAlphanumericSegment('ABC-42')	alphanumeric
addByteSegment(buf)	byte
addSegment(segment)	explicit QRCodeSegment
addSegments(...segments)	bulk, accepts spread SegmentArray

QRCodeDecoder

decode() accepts every shape the encoder produces:

const decoder = new QRCodeDecoder();

await decoder.decode(pngBuffer);                    // Buffer / Uint8Array (PNG, JPEG, ...)
await decoder.decode('data:image/png;base64,...');  // data URL
await decoder.decode(rawBase64String);              // raw base64
await decoder.decode(readableStream);               // Readable of an encoded image
await decoder.decode({ data, width, height });      // raw RGBA pixels

// file via constructor options
await new QRCodeDecoder({ type: 'file', path: 'qr.png' }).decode();

Resolves with the jsQR result object (data, binaryData, location, ...) or null when no QR code is found. Unsupported input throws TypeError.

License

MIT