"Multipart/ form -data“在React-redux表单上载中不起作用

import React from 'react';
import { useDispatch } from 'react-redux';
import { submitForm } from './actions';

const FileUploadForm = () => {
  const dispatch = useDispatch();

  const handleSubmit = (event) => {
    event.preventDefault();
    const formData = new FormData(event.target);
    dispatch(submitForm(formData));
  };

  return (
    <form onSubmit={handleSubmit}>
      <input type="file" name="file" />
      <button type="submit">Upload</button>
    </form>
  );
};

export default FileUploadForm;

const express = require('express');
const multer = require('multer');
const upload = multer({ dest: 'uploads/' });

const app = express();

app.post('/upload', upload.single('file'), (req, res) => {
  res.send('File uploaded successfully');
});

app.listen(3000, () => {
  console.log('Server started on port 3000');
});

const cors = require('cors');

app.use(cors());