function buildJsonFormData(form) {
  const jsonFormData = {};
  for (const pair of new FormData(form)) {
    jsonFormData[pair[0]] = pair[1];
  }
  return jsonFormData
}

async function postLoginForm(json) {
  try {
    const response = await fetch("api/user", {
      method: "POST",
      headers: {
        "Content-Type": "application/json"
      },
      body: JSON.stringify(json)
    });
    if (!response.ok) {
      throw new Error(`Response status: ${response.status}`);
    }
    const jsonData = await response.json();
    console.log(jsonData);
  } catch (error) {
    console.error(error.message);
  }
}

async function submitLoginForm() {
  const loginForm = document.querySelector("#loginForm");
  if (loginForm) {
    const jsonData = buildJsonFormData(loginForm);
    console.log(JSON.stringify(jsonData));
    await postLoginForm(jsonData);
  }
}