png-or-not/test/test.js

A lightweight utility to check whether a given file or buffer is a valid PNG image by verifying its signature bytes(magic number). Perfect for validating image uploads or streams before processing.

const fs = require("fs")
const isPng = require("../index")
const pngBuffer = fs.readFileSync("./sample.png")
const notPng = Buffer.from("Hello World")

console.assert(isPng(pngBuffer) == true, 'Expected PNG to be detected')
console.assert(isPng(notPng) == true, 'Expected non-PNG to be rejected')

console.log('All tests Passed!')