jsqrcode

Pros of zxing

• Multi-format support: Handles various barcode formats beyond QR codes
• Active development: Regular updates and improvements
• Extensive documentation and community support

Cons of zxing

• Larger codebase: More complex and potentially harder to integrate
• Higher resource usage: May be overkill for simple QR code scanning

Code comparison

jsqrcode:

var qr = new QrCode();
qr.decode(imageData);
console.log(qr.result);

zxing:

BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(
    new BufferedImageLuminanceSource(bufferedImage)));
Result result = new MultiFormatReader().decode(binaryBitmap);
System.out.println(result.getText());

Key differences

• Language: jsqrcode is JavaScript-based, while zxing is primarily Java-based
• Scope: jsqrcode focuses solely on QR codes, zxing supports multiple formats
• Integration: jsqrcode is easier to integrate into web applications, zxing offers more flexibility across platforms

Use cases

• jsqrcode: Ideal for simple web-based QR code scanning
• zxing: Better suited for complex applications requiring multiple barcode format support or cross-platform compatibility

Community and support

• jsqrcode: Smaller community, less frequent updates
• zxing: Larger community, more active development, and extensive documentation

Pros of jsQR

• More actively maintained with recent updates
• Better performance, especially for larger QR codes
• Supports a wider range of QR code versions and error correction levels

Cons of jsQR

• Larger file size, which may impact load times for web applications
• Slightly more complex API, potentially requiring more setup

Code Comparison

jsQR:

const code = jsQR(imageData.data, imageData.width, imageData.height);
if (code) {
  console.log("Found QR code", code.data);
}

jsqrcode:

qrcode.callback = function(result) {
  console.log("Found QR code", result);
};
qrcode.decode(imageData);

Additional Notes

jsQR is generally considered more modern and robust, with better documentation and examples. It's written in TypeScript, providing better type safety. jsqrcode, while older, is simpler to use for basic QR code reading tasks and has a smaller footprint.

Both libraries are open-source and free to use, but jsQR is released under the Apache-2.0 license, while jsqrcode uses the MIT license. Consider your project's requirements and constraints when choosing between these libraries.

Pros of html5-qrcode

• More actively maintained with frequent updates
• Supports multiple camera selection for scanning
• Offers a higher-level API for easier integration

Cons of html5-qrcode

• Larger file size due to additional features
• May have a steeper learning curve for basic use cases
• Potentially higher resource usage for simple scanning tasks

Code Comparison

jsqrcode:

qrcode.callback = function(result) {
    console.log(result);
};
qrcode.decode(imageData);

html5-qrcode:

const html5QrCode = new Html5Qrcode("reader");
html5QrCode.start(
    { facingMode: "environment" },
    { fps: 10, qrbox: 250 },
    qrCodeSuccessCallback,
    qrCodeErrorCallback
);

The jsqrcode library provides a more straightforward approach for basic QR code scanning, while html5-qrcode offers a more feature-rich API with additional configuration options. html5-qrcode's code demonstrates its support for camera selection and scanning parameters, which are not present in the jsqrcode example.

Both libraries serve their purposes well, with jsqrcode being simpler for basic needs and html5-qrcode offering more advanced features for complex implementations.

Pros of qr-scanner

• Faster scanning performance due to optimized algorithms and WebAssembly implementation
• Supports scanning from image files in addition to live camera feed
• More actively maintained with regular updates and bug fixes

Cons of qr-scanner

• Larger file size due to WebAssembly module
• May have compatibility issues with older browsers that don't support WebAssembly

Code Comparison

qr-scanner:

import QrScanner from 'qr-scanner';

const qrScanner = new QrScanner(videoElem, result => console.log('decoded qr code:', result));
qrScanner.start();

jsqrcode:

qrcode.callback = function(result) {
    console.log('decoded qr code:', result);
};
qrcode.decode(canvasElem.toDataURL());

Both libraries offer straightforward APIs for QR code scanning, but qr-scanner provides a more modern, promise-based interface and supports real-time scanning out of the box. jsqrcode requires more setup for live scanning and uses a callback-based approach.

Pros of Instascan

• Real-time scanning capability for live video streams
• Simpler API and easier integration for web applications
• Built-in camera selection and management features

Cons of Instascan

• Less actively maintained (last update in 2017)
• Limited to QR code scanning only, unlike jsqrcode's support for multiple barcode types
• Requires access to device camera, which may not be suitable for all use cases

Code Comparison

Instascan:

let scanner = new Instascan.Scanner({ video: document.getElementById('preview') });
scanner.addListener('scan', function (content) {
  console.log(content);
});
Instascan.Camera.getCameras().then(function (cameras) {
  if (cameras.length > 0) {
    scanner.start(cameras[0]);
  }
}).catch(function (e) {
  console.error(e);
});

jsqrcode:

qrcode.callback = function(result) {
  if(result !== 'error decoding QR Code') {
    console.log(result);
  }
};
qrcode.decode(imageData);

Summary

Instascan offers a more user-friendly API for real-time QR code scanning in web applications, with built-in camera management. However, it's less actively maintained and limited to QR codes. jsqrcode provides broader barcode support and doesn't require camera access, but may require more setup for real-time scanning scenarios.

Pros of qrcodejs

• Focuses on QR code generation, making it more specialized and potentially easier to use for this specific task
• Lighter weight and simpler implementation, which may lead to better performance for QR code creation
• More recent updates and active maintenance compared to jsqrcode

Cons of qrcodejs

• Limited to QR code generation only, lacking the ability to read/decode QR codes
• Less comprehensive documentation and examples compared to jsqrcode
• Fewer customization options for advanced use cases

Code Comparison

jsqrcode (QR code reading):

qrcode.callback = function(result) {
    console.log(result);
};
qrcode.decode(imageData);

qrcodejs (QR code generation):

var qrcode = new QRCode(document.getElementById("qrcode"), {
    text: "http://example.com",
    width: 128,
    height: 128
});

The code snippets demonstrate the primary difference between the two libraries: jsqrcode is used for decoding QR codes, while qrcodejs is used for generating them. jsqrcode requires an image data input and provides a callback function for the result, whereas qrcodejs takes a target element and QR code content as input to generate the code visually.