image-type

Detect the image type of a Buffer/Uint8Array

See the file-type module for more file types and a CLI.

Install

$ npm install image-type

Usage

Node.js

const readChunk = require('read-chunk');
const imageType = require('image-type');

const buffer = readChunk.sync('unicorn.png', 0, 12);

imageType(buffer);
//=> {ext: 'png', mime: 'image/png'}

Or from a remote location:

const https = require('https');
const imageType = require('image-type');

const url = 'https://upload.wikimedia.org/wikipedia/en/a/a9/Example.jpg';

https.get(url, response => {
	response.on('readable', () => {
		const chunk = response.read(imageType.minimumBytes);
		response.destroy();
		console.log(imageType(chunk));
		//=> {ext: 'jpg', mime: 'image/jpeg'}
	});
});

Browser

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

xhr.onload = () => {
	imageType(new Uint8Array(this.response));
	//=> {ext: 'png', mime: 'image/png'}
};

xhr.send();

API

imageType(input)

Returns an Object with:

• ext - One of the supported file types
• mime - The MIME type

Or null when there is no match.

input

Type: Buffer | Uint8Array

It only needs the first .minimumBytes bytes.

imageType.minimumBytes

Type: number

The minimum amount of bytes needed to detect a file type. Currently, it's 4100 bytes, but it can change, so don't hardcode it.

Supported file types

• jpg
• png
• gif
• webp
• flif
• cr2
• tif
• bmp
• jxr
• psd
• ico
• bpg
• jp2 - JPEG 2000
• jpm - JPEG 2000
• jpx - JPEG 2000
• heic
• cur
• dcm - DICOM Image File

SVG isn't included as it requires the whole file to be read, but you can get it here.