Javascript 从React本机应用程序向Express api发送CSV文件

我已经为此苦苦挣扎了好几个小时，却找不到正确的解决方案。所以基本上我有一个REST API，它看起来像这样：

   //multer config
const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, "");
  },
  filename: function (req, file, cb) {
    cb(null, new Date().valueOf() + "-" + file.originalname);
  },
});

const upload = multer({
  storage,
  limits: {
    fileSize: 30 * 1024 * 1024,
  },
}).single("list");

app.post("/", upload, function (req, res) {
  // console.log(dataURLtoFile(req.body,'list'))
  console.log(req.body);
  CSVToJSON()
    .fromFile(req.file.path)
    .then((source) => {
      source.forEach((res) => {
        firebase
          .firestore()
          .collection("races")
          .add(res)
          .then(() => {});
      });
    })
    .then(() => {
      fs.unlinkSync(req.file.path);
    });

  res.send("All good");

  console.log(req.body);
});

Object {
  "name": "biostats.csv",
  "size": 849,
  "type": "success",
  "uri": "file:///data/user/0/host.exp.exponent/cache/ExperienceData/%2540yawning%252FChatOneonOne/DocumentPicker/218c8859-4bdb-4af4-ac61-f1c71688cca5.csv",
}

因此，它接收CSV文件，将其保存在本地，将其转换为JSON，将JSON发送到Firebase Firestore并删除临时CSV文件。当前端是一个普通的HTML表单时，它工作得很好，但是当我尝试用expo document picker上传它时，它就不起作用了。我得到的是一个如下所示的对象：

   //multer config
const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, "");
  },
  filename: function (req, file, cb) {
    cb(null, new Date().valueOf() + "-" + file.originalname);
  },
});

const upload = multer({
  storage,
  limits: {
    fileSize: 30 * 1024 * 1024,
  },
}).single("list");

app.post("/", upload, function (req, res) {
  // console.log(dataURLtoFile(req.body,'list'))
  console.log(req.body);
  CSVToJSON()
    .fromFile(req.file.path)
    .then((source) => {
      source.forEach((res) => {
        firebase
          .firestore()
          .collection("races")
          .add(res)
          .then(() => {});
      });
    })
    .then(() => {
      fs.unlinkSync(req.file.path);
    });

  res.send("All good");

  console.log(req.body);
});

Object {
  "name": "biostats.csv",
  "size": 849,
  "type": "success",
  "uri": "file:///data/user/0/host.exp.exponent/cache/ExperienceData/%2540yawning%252FChatOneonOne/DocumentPicker/218c8859-4bdb-4af4-ac61-f1c71688cca5.csv",
}

我正在做的基本上是尝试将URI部分转换为blob，因为我已经用一个图像完成了这项工作，并且工作正常。以下是我的上传功能：

const uploadImage = async () => {
    // Check if any file is selected or not

    const fd = new FormData();
    if (singleFile != null) {
      const toUpload = singleFile
      const response = await fetch(toUpload);
      const blob = await response.blob();
    
        fd.append("list", blob);
        fetch("http://192.168.1.163:5000/", {
        method: "POST",
        body: fd,
        headers: {
          "Content-Type": "multipart/form-data",
        },
      }).then(res => console.log(res)).catch(err => console.log(err.message))
    
      }
      };
      
    }

所以我现在非常绝望，不知道如何继续。如果有人知道怎么做，请分享。我欠你一个人情