Node.js 如何使用multer-s3转换图像？

我试图在上传到AmazonS3之前调整图像的大小。我已经找到了关于如何实现这一点的文档，但我怀疑我的实现是不正确的。我包括下面的代码。我做错了什么

const multerFilter = (req, file, cb) => {
  if (file.mimetype.startsWith('image')) {
    cb(null, true);
  } else {
    cb(new AppError('Not an image! Please upload images only.', 400), false);
  }
};

const upload = multer({
  storage: multerS3({
    s3: s3,
    acl: 'public-read',
    bucket: 'BUCKETNAME',
    contentType: multerS3.AUTO_CONTENT_TYPE,
  }),
  fileFilter: multerFilter,
  shouldTransform: function (req, file, cb) {
    cb(null, /^image/i.test(file.mimetype));
  },
  transforms: [
    {
      id: 'original',
      key: function (req, file, cb) {
        cb(null, 'image-original.jpg');
      },
      transform: function (req, file, cb) {
        cb(null, sharp().resize(100, 100).jpg());
      },
    },
  ],
});

---

我能弄明白这一点。下面的代码使用npm的multer-s3-image-transform工作

const upload = multer({
  storage: multerS3({
    s3: s3,
    acl: 'public-read',
    bucket: 'BUCKETNAME',
    contentType: multerS3.AUTO_CONTENT_TYPE,
    transforms: () =>
      sharp().resize(250, 250).jpeg({
        progressive: true,
        quality: 80,
      }),
  }),
  fileFilter: multerFilter,
});

---

我能弄明白这一点。下面的代码使用npm的multer-s3-image-transform工作

const upload = multer({
  storage: multerS3({
    s3: s3,
    acl: 'public-read',
    bucket: 'BUCKETNAME',
    contentType: multerS3.AUTO_CONTENT_TYPE,
    transforms: () =>
      sharp().resize(250, 250).jpeg({
        progressive: true,
        quality: 80,
      }),
  }),
  fileFilter: multerFilter,
});