send multiple form data to express API with multer

I want to send form data including a file to my express API for adding churches in my database and i want to upload church details and an image for this.
this is my HTML form :

        <form action="" id="ad-bis">
          <div class="form-group">
            <label>INTRODU NUMEle BISERICII</label>
            <input
              type="text"
              name="biserica"
              id="biserica"
              class="form-control"
            />
            <span id="error_biserica" class="text-danger"></span>
          </div>
          <div class="form-group">
            <label>INTRODU ORASUL</label>
            <input type="text" name="oras" id="oras" class="form-control" />
            <span id="error_oras" class="text-danger"></span>
          </div>
          <div class="form-group">
            <label>INTRODU ADRESA</label>
            <input type="text" name="adresa" id="adresa" class="form-control" />
            <span id="error_adresa" class="text-danger"></span>
          </div>
          <div class="form-group">
            <label>INTRODU NUME PREOT</label>
            <input type="text" name="preot" id="preot" class="form-control" />
            <span id="error_preot" class="text-danger"></span>
          </div>
          <div class="form-group">
            <label for="poza">ADAUGA POZA</label>
            <input type="file" id="poza" />
          </div>
          <div class="form-group" align="center">
            <button type="submit" name="save" id="save" class="btn btn-info">
              SALVARE
            </button>
          </div>
        </form>

in my js file i created submit function:

adBis.addEventListener("submit", async e => {
  e.preventDefault();
  const data = new FormData();
  data.append(
    "data",
    JSON.stringify({
      nume: document.querySelector("#biserica").value,
      oras: document.querySelector("#oras").value,
      adresa: document.querySelector("#adresa").value,
      preot: document.querySelector("#preot").value,
      uid: localStorage.getItem("uid")
    })
  );
  data.append("poza", _("#poza").files[0]);
  console.log(data);
  const res = await await fetch("http://localhost:8080/api/site/adaugare", {
    method: "POST",
    body: data
  });
  const serverData = await res.json();
  console.log(res, serverData);
  _(".info").style.display = "none";
  if (!serverData.success) {
    afisareEroare(data.msg);
  }
  console.log("ok");
  await afisRezultate(localStorage.getItem("uid"));
});

then i created endpoint in express using multer tu upload file:

const multer = require("multer");
const storage = multer.diskStorage({
  destination: function(req, file, cb) {
    cb(null, "../images");
  },
  filename: function(req, file, cb) {
    cb(null, file.fieldname + "_" + Date.now() + "_" + file.originalname);
  }
});

const upload = multer({
  storage: storage
}).array("imgUploader", 3);

outer.post("/adaugare", (req, res) => {
  console.log(req.body);
  res.json({ msg: "ok" });
  /*
 
    */
});

in my console, req.body is empty how send all data?
I tried with firebase storage but it doesn't work for me.
what I missed?
thanks!

First tip: Since you are using FormData you can pass the form in to get automatically all the values in the form.

Second, here you are awaiting twice:

const res = await await fetch("http://localhost:8080/api/site/adaugare", [...]

Lastly req.body empty is either because of lack of body-parser or, as I see here, you have not added the enctype="multipart/form-data" attribute, without this Multer won't get any data from your form.