无法更改MongoDB GridFS中的存储桶名称？

Question

我正在尝试使用GridFS和Mongoose将视频上传到数据库，但它将Bucket Name保持为fs

let gfss;
  const conn = mongoose.createConnection('mongodb://localhost:27017/zaad');
  conn.once('open',()=>{
    gfss = Grid(conn.db,mongoose.mongo);
    gfss.collection('lessonVideo');
  });

const storage = new GridFsStorage({
    url:config.uri,
    file:(req,file)=>{
      if(!req.params.id){
        console.log('no id provided');
      }else{
        User.findOne({_id:req.decoded.user},(err,user)=>{
          if(err){
            console.log(err);
          }else{
            Lesson.findOne({_id:req.params.id},(err,lesson)=>{
              if(err){
                console.log(err);
              }else{
                if(!lesson){
                  console.log('lesson does not exits');
                }else{
                  if(lesson.createbById == req.decoded.userId){
                    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 metadata = req.params.id;
                        const fileinfo = {
                          filename:filename,
                          metadata:metadata,
                          bucketName:'lessonVideo'
                        };
                        resolve(fileinfo);
                      });
                    });
                  }else{
                    console.log('your not authentication to this file');
                  }
                }
              }
            });
          }
        });
      }
    }
  });

const upload = multer({storage});
  router.post('/lessonVideo/:id',upload.single('file'),(req,res)=>{
    if(!req.file){
      res.json({success:false , message:'no image was provided'});
    }else{
      console.log(req.decoded.userId);
      res.json({success:true , message:'done'});

    }
  });

但它保留了存储桶名称fs

当我删除它工作的所有if语句但当我使用它们时，存储桶名称更改为fs