@qr-plus/core

Zero-dependency QR code generator written in TypeScript. Implements ISO/IEC 18004 standard.

Migrated from qr-pure — if you were using qr-pure, simply change your import to @qr-plus/core. The API is identical.

Features

• Zero dependencies for core functionality
• Supports all 40 QR versions (21x21 to 177x177 modules)
• 4 error correction levels: L (7%), M (15%), Q (25%), H (30%)
• 3 encoding modes: Numeric, Alphanumeric, Byte with auto-detection
• Automatic version and mask selection
• 3 renderers: Canvas, SVG (with module shapes), Terminal (ASCII/Unicode)
• Dual CJS + ESM build with TypeScript declarations
• 350+ unit/integration tests + E2E verification with jsQR

Installation

npm install @qr-plus/core

Usage

Quick Start

import { generateQR, renderToSVG, renderToTerminal } from "@qr-plus/core";

// Generate QR matrix
const { matrix } = generateQR("Hello World");

// Render as SVG string
const svg = renderToSVG("Hello World", { scale: 10 });

// Print to terminal
console.log(renderToTerminal("Hello World"));

With Options

import { QRCode } from "@qr-plus/core";

const qr = new QRCode("Hello World", {
  errorCorrectionLevel: "H", // L, M, Q, H
  version: "auto", // 1-40 or 'auto'
  mode: "auto", // numeric, alphanumeric, byte, or 'auto'
  mask: "auto", // 0-7 or 'auto'
});

const { matrix, version, size, mode, maskPattern } = qr.generate();

Render to Canvas

import { QRCode, CanvasRenderer } from "@qr-plus/core";

const qr = new QRCode("Hello World");
const { matrix } = qr.generate();

const canvas = document.getElementById("qr-canvas") as HTMLCanvasElement;
CanvasRenderer.render(canvas, matrix, {
  scale: 10,
  margin: 4,
  darkColor: "#000000",
  lightColor: "#ffffff",
});

Render to SVG

import { SVGRenderer } from "@qr-plus/core";

// Standard squares
const svg = SVGRenderer.render(matrix, { scale: 10 });

// Rounded modules
SVGRenderer.render(matrix, { moduleShape: "rounded", cornerRadius: 0.3 });

// Circle or dot modules
SVGRenderer.render(matrix, { moduleShape: "circle" });
SVGRenderer.render(matrix, { moduleShape: "dot" });

Render to Terminal

import { TerminalRenderer } from "@qr-plus/core";

// Unicode blocks (best contrast)
console.log(TerminalRenderer.render(matrix));

// Compact mode (half height)
console.log(TerminalRenderer.render(matrix, { style: "compact" }));

// ASCII (max compatibility)
console.log(TerminalRenderer.render(matrix, { style: "ascii" }));

// Inverted for dark backgrounds
console.log(TerminalRenderer.render(matrix, { invert: true }));

API

QRCode

new QRCode(data: string, options?: QRCodeOptions)

Options:

• errorCorrectionLevel: 'L' | 'M' | 'Q' | 'H' (default: 'M')
• version: 1-40 | 'auto' (default: 'auto')
• mode: 'numeric' | 'alphanumeric' | 'byte' | 'auto' (default: 'auto')
• mask: 0-7 | 'auto' (default: 'auto')

Methods:

• generate(): Returns { matrix, version, size, mode, maskPattern }

Helper Functions

generateQR(content, options?)           // → QRCodeResult
renderToCanvas(canvas, content, options?) // → void
renderToSVG(content, options?)          // → string
renderToTerminal(content, options?)     // → string

CanvasRenderer

CanvasRenderer.render(canvas, matrix, options?)
CanvasRenderer.toDataURL(matrix, options?)
CanvasRenderer.toBlob(matrix, options?)

SVGRenderer

SVGRenderer.render(matrix, options?)
// options: scale, margin, darkColor, lightColor, moduleShape, cornerRadius

TerminalRenderer

TerminalRenderer.render(matrix, options?)
// options: style ('unicode' | 'compact' | 'ascii'), margin, invert

Development

This package is part of the @qr-plus monorepo. See the root README for setup instructions.

# From the monorepo root
pnpm install         # Install all dependencies
pnpm run build       # Build all packages
pnpm run test        # Run all tests (unit + integration + E2E)
pnpm run typecheck   # Type check
pnpm run lint        # Lint

# Or run commands scoped to the core package
pnpm --filter @qr-plus/core test
pnpm --filter @qr-plus/core build

Documentation

• API Reference — generated with TypeDoc, deployed on GitHub Pages
• Technical Documentation
• Changelog
• Roadmap

License

MIT