is-png

What is is-png?

The is-png npm package is a utility that allows you to check if a given buffer or file is a PNG image. It is useful for validating image formats in various applications.

What are is-png's main functionalities?

Check if a buffer is a PNG

This feature allows you to check if a given buffer contains a PNG image. You can read a file into a buffer and then use the isPng function to validate its format.

const isPng = require('is-png');
const fs = require('fs');

const buffer = fs.readFileSync('path/to/image.png');
console.log(isPng(buffer)); // true if the buffer is a PNG, false otherwise

Check if a file is a PNG

This feature allows you to check if a given file is a PNG image by reading the file asynchronously and then using the isPng function to validate its format.

const isPng = require('is-png');
const fs = require('fs');

fs.readFile('path/to/image.png', (err, data) => {
  if (err) throw err;
  console.log(isPng(data)); // true if the file is a PNG, false otherwise
});

Other packages similar to is-png

image-type

The image-type package detects the file type of a buffer, supporting various image formats including PNG, JPEG, GIF, and more. It provides broader functionality compared to is-png, which is specific to PNG images.

file-type

The file-type package is a comprehensive utility for detecting the file type of a buffer or stream. It supports a wide range of file formats, including images, videos, documents, and more. It offers more extensive functionality compared to is-png, which is focused solely on PNG images.

is-jpg

The is-jpg package is similar to is-png but is specific to JPEG images. It allows you to check if a given buffer or file is a JPEG image, providing similar functionality but for a different image format.

README

is-png

Check if a Buffer/Uint8Array is a PNG image

Used by image-type.

Install

$ npm install --save is-png

Usage

Node.js

var readChunk = require('read-chunk'); // npm install read-chunk
var isPng = require('is-png');
var buffer = readChunk.sync('unicorn.png', 0, 4);

isPng(buffer);
//=> true

Browser

var xhr = new XMLHttpRequest();
xhr.open('GET', 'unicorn.png');
xhr.responseType = 'arraybuffer';

xhr.onload = function () {
	isPng(new Uint8Array(this.response));
	//=> true
};

xhr.send();

API

isPng(buffer)

Accepts a Buffer (Node.js) or Uint8Array.

It only needs the first 4 bytes.

License

MIT © Sindre Sorhus