I use this script to upload a file via browser:
function onSubmit() {
    const url = 'uploadURl';
    fetch(url, {
            method: 'POST',
            body: input.files[0]
        }).then(function(res) {
            console.log(res);
            location.reload();
        })
        .catch(function(err) {
            console.error('Got error:', err);
        });
}
It works fine, but I would like to use $.ajax instead of fetch.
How can it be rewritten? In particular, I still did not get how to properly setup the request body for the file.
Update:
If I write:
$.post({
    url: 'uploadUrl',
    { data: input.files[0] }
})
.done(function() {
    console.log('File uploaded');
});
I get: Uncaught SyntaxError: Unexpected token {
 
    