Node.js ReactJS上传文件到Express后端未定义

我正在尝试使用FormData从reactjs将profilePhoto上载到express后端：

    const form = new FormData();
        form.append(user, "user");
     
        form.append(profilePhoto, "profilePhoto");
  axios({
      method: "post",
      url: "http://localhost:8082/candidate/addCandidate",
      data: form,
      headers: { "Content-Type": "multipart/form-data" },
    })
      .then(function (response) {
        //handle success
        console.log(response);
      })
      .catch(function (response) {
        //handle error
        console.log(response);
      });

在后端：（这与邮递员配合得很好，图像被添加到后端） const DIR=“/public/”

然而，当我试图上传一个文件时，它不会被上传到后端，我会得到

req.file未定义的

。我试着去安慰req，这就是我得到的结果： {'606aee02f057cd714db2b646'：'user'，'[object File]：'profilePhoto'}

---

任何帮助

我认为您误用了formData.append，它应该是formData.append（“key”，value），所以在您的示例中：form.append（“user”，user）@Haythemfarhats天与这个问题斗争！你救了我。它起作用了

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, DIR);
  },
  filename: (req, file, cb) => {
    const fileName = file.originalname.toLowerCase().split(" ").join("-");
    cb(null, uuid() + "-" + fileName);
  },
});

var upload = multer({
  storage: storage,
  fileFilter: (req, file, cb) => {
    if (
      file.mimetype === "image/png" ||
      file.mimetype === "image/jpg" ||
      file.mimetype === "image/jpeg"
    ) {
      cb(null, true);
    } else {
      cb(null, false);
      return cb(new Error("Only .png, .jpg and .jpeg format allowed!"));
    }
  },
});

router.post(
  "/addCandidate",
  upload.single("profilePhoto"),
  (req, res, next) => {
    const url = req.protocol + "://" + req.get("host");

    // try {
    const candidate = new Candidate({
      user: req.body.user,
      profilePhoto: url + "/public/" + req.file,
    });
    candidate
      .save()
      .then((result) => {
        console.log("bbbbbbbbbbbb", req);
        res.status(201).json({
          message: "User registered successfully!",
          profilePhoto: result.profilePhoto,
        });
      })
      .catch((err) => {
        console.log("aaaaaaaaaaaa", req.body.file);
        res.status(500).json({ error: err });
        console.log(err);
      });
  }
);