How to import files on Memory using Multer on Express(Nodejs)

const { Router } = require('express')
const multer = require('multer')
const router = router

const storage = multer.memoryStorage()
const upload  = multer({ storage: storage})

const func = async (req, res) => {
  console.log(typeof req.file) // buffer
  console.log(typeof req.file.buffer)
  
  // send image back
  if (req.file.memetype === 'image/jpg'){
    res.set('Content-Type', 'image/jpg')
    res.send(req.file.buffer)
  } else {
    res.send('it is not image')
  }
}

router.route('/upload')
  .post(upload.single('file'), func)