➊

const s3 = new S3Client({
  credentials: {
    accessKeyId: process.env.S3_ACCESS_KEY_ID,
    secretAccessKey: process.env.S3_SECRET_ACCESS_KEY,
  },
  region: 'ap-northeast-2',

});

➋

const upload = multer({
  storage: multerS3({
    s٣,
    bucket: 'nodebird33',
    key(req, file, cb) {
      cb(null, `original/${Date.now()}_${file.originalname}`);
    },
  }),
  limits: { fileSize: 5 * 1024 * 1024 },
});
...