async function ajax({
  method = "GET",
  url = ".",
  body = undefined,
  headers = {},
  on_success = () => {},
  on_failure = () => {},
}) {
  const xhttp = new XMLHttpRequest();
  const return_on_sent = new Promise((resolve, reject) => {
    try {
      xhttp.onreadystatechange = () => {
        if (xhttp.readyState == 4) {
          const response_status = String(xhttp.status);
          if (/2\d\d/.test(response_status)) {
            resolve(on_success(xhttp.responseText, xhttp));
          } else {
            resolve(on_failure(xhttp.responseText, xhttp));
          }
        }
      };
    } catch (err) {
      reject(err);
    }
  });

  xhttp.open(method, url, true);
  Object.keys(headers).forEach((header_key) => {
    xhttp.setRequestHeader(header_key, headers[header_key]);
  });
  xhttp.send(body);

  return return_on_sent;
}