Refactoring Multer diskStorage instance using Javascript Closures (before refactor)

cats.js

const router = require('express').Router();
const multer = require('multer');

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, './cats');
  },
  filename: (req, file, cb) => {
    const fname = `${Date.now()}-${encodeURIComponent(file.originalname)}`;
    cb(null, fname);
  },
});

const upload = multer({ storage });

router.post('/', upload.array('photos', 10), (req, res) => {
 // handle logic
});

module.exports = router;

dogs.js

const router = require('express').Router();
const multer = require('multer');

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, './dogs');
  },
  filename: (req, file, cb) => {
    const fname = `${Date.now()}-${encodeURIComponent(file.originalname)}`;
    cb(null, fname);
  },
});

const upload = multer({ storage });

router.post('/', upload.array('photos', 10), (req, res) => {
 // handle logic
});

module.exports = router;