How to accept an image on the server?

Question

JavaScript

On the client I do:

let button = document.getElementById('btn')
button.onclick = () => {
    var formData = new FormData();
    formData.append("zdarov", document.getElementById("file").files[0], 'a.png');
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "http://localhost:3000/api");
    xhr.send(formData);
}

And the server receives an empty object:

router.post('/api', ctx => {
    ctx.status = 200
    console.log(ctx.request.body)
})

Answer 1

https://www.npmjs.com/package/koa-multer