Node.js Multer.Multer中间件是'；t响应/工作

我曾试图使用multer和multer-gridfs-storage将IMG保存到mongodb中。每次我尝试使用请求上载IMG时，我都会得到未定义的内容，而且我还有几个控制台日志到中间件中，但它们不能像multer本身那样工作。无论是前/后，文件名都是相同的

express
let conn = mongoose.connection;

//-----------Multer--------------

conn.once('open', () => {
  gfs = Grid(conn.db, mongoose.mongo);
  gfs.collection('uploads');
});

const storage = new GridFsStorage({
  url: process.env.MONGO_URI,
  file: (req, file) => {
    console.log(file, 'file from multer');
    return new Promise((resolve, reject) => {
      crypto.randomBytes(16, (err, buf) => {
        if (err) {
          return reject(err);
        }
        const filename = buf.toString('hex') + path.extname(file.originalname);
        const fileInfo = {
          filename: filename,
          bucketName: 'uploads',
        };
        resolve(fileInfo);
        console.log(fileInfo, 'file info from GridFs');
      });
    });
  },
});

const upload = multer({storage});

//--------------Routes
router.post(
  '/api/profile/upload/avatar',
  upload.single('downloadAvatar'),
  (req, res) => {
    console.log(req.files, 'req.files');
  }
);

反应
setFile（e.target.files）}
/>
export const uploadAvatar=（文件）=>async（分派）=>{
const res=wait api.post（'/api/profile/upload/avatar'，file）；
console.log（res.data，'数据操作'）；
分派（{type:types.UPLOAD_AVATAR，payload:res.data}）；
};

React
      <form
        action='/api/profile/upload/avatar'
        className='downloadButton'
        encType='multipart/form-data'
      >
        <label htmlFor='downloadAvatar'>
          <AddIcon></AddIcon>
          <input
            name='downloadAvatar'
            id='downloadAvatar'
            type='file'
            accept='image/'
            style={{display: 'none'}}
            onChange={(e) => setFile(e.target.files)}
          />
        </label>
      </form>

export const uploadAvatar = (file) => async (dispatch) => {
  const res = await api.post('/api/profile/upload/avatar', file);
  console.log(res.data, 'data action ');
  dispatch({type: types.UPLOAD_AVATAR, payload: res.data});
};