I have an XHR post request as follows:

    const xhr = new XMLHttpRequest();
    const formData = new FormData();
    const inpFile = document.getElementById("inpFile");

    var numFiles = inpFile.files.length;
    for (let i = 0; i < numFiles; i++) {
        formData.append("file", inpFile.files[i]);
    }

    xhr.open("POST", "https://submit.com.xz");
    xhr.send(formData);

Once I post the form data to the server, or in this instance, a cloud function, I'd like to decode the file, store it as inpFile and send another very similar XMLHttpRequest.

Would appreciate some advice on how to do this as I'm having difficulty extracting the file from the original XMLHttpRequest.