png-or-not

A lightweight Node.js utility to check whether a given buffer contains a valid PNG image, by verifying its magic number (signature bytes).

📦 Installation

npm install png-or-not

🚀 Usage

const fs = require('fs');
const isPng = require('png-or-not');

// Read a file into a buffer
const buffer = fs.readFileSync('image.png');

console.log(isPng(buffer)); // true if it's a PNG, false otherwise

📘 API

isPng(buffer: Buffer): boolean

• Parameters: buffer — a Node.js Buffer
• Returns: true if the buffer starts with the PNG file signature, false otherwise
• Note: The function does not decode the image — it only checks the file signature

🧪 Testing

You can run the included test script:

npm test

Make sure to place a valid sample.png file in the test/ directory.

📄 License

MIT © 2025 Abhay Patel