import {readChunk} from 'read-chunk';
import imageType from 'image-type';

const buffer = await readChunk('unicorn.png', {length: 12});

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

import https from 'node:https';
import imageType from 'image-type';

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

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

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

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

xhr.send();