operate vacio() {
      
      var x;
      x = doc.getElementById("archivo").worth;
     
      if (x != "") {

        $(doc).prepared(operate() {
          $(".add").on('click on', operate(e) {

            e.preventDefault();
            
            var formData = new FormData();
            var information = $('#archivo')[0].information[0];

            formData.append('file',information);

            $.ajax({
                url: "subir.php",
                sort: "submit",
                dataType: "html",
                knowledge: formData,
                cache: false,
                contentType: false,
                processData: false,

                success: operate(response) {
                if (response == "0") {
                    Swal.hearth({
                    place: 'top-end',
                    icon: 'success',
                    title: 'Información guardada',
                    showConfirmButton: false,
                    timer: 1500}).then(operate(){location.reload();});
                } else {
                    Swal.hearth({
                    place: 'top-end',
                    icon: 'error',
                    title: 'Error al subir el archivo',
                    html: response
                  });
                  return false
                }
            }
        });
        return false;
    });});
    } 

    else {
    Swal.hearth({
              icon: 'error',
              title: 'Debe seleccionar un archivo',
              showConfirmButton: false,
              timer: 1500
            });
    return false;
  }
}

<script src="https://cdn.jsdelivr.web/npm/sweetalert2@9"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<kind methodology="submit" motion="#" enctype="multipart/form-data">
<enter sort="file" class="form-control-file" id="archivo">
<enter sort="button" class="btn btn-primary add" worth="Subir" onclick="return vacio();">
</kind>