is-jpg

Check if a Buffer/Uint8Array is a JPEG image

Install

 npm install is-jpg

Usage

Node.js

 import {readChunk} from 'read-chunk';
import isJpg from 'is-jpg';

const buffer = await readChunk('unicorn.jpg', {length: 3});

isJpg(buffer);
//=> true

Browser

 const xhr = new XMLHttpRequest();
xhr.open('GET', 'unicorn.jpg');
xhr.responseType = 'arraybuffer';

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

xhr.send();

API

isJpg(buffer)

Accepts a Buffer (Node.js) or Uint8Array.

It only needs the first 3 bytes.

Related

• file-type - Detect the file type of a Buffer/Uint8Array