Image Upload Error: TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received type undefined

exports.uploadImage = (req, res) => {
  const BusBoy = require('busboy')
  const path = require('path')
  const os = require('os')
  const fs = require('fs')

  const busboy = new BusBoy({
    headers: req.headers
  })

  let imageFileName
  let imageToBeUploaded = {}

  busboy.on('file', (fieldname, file, filename, encoding, mimetype) => {

    console.log(fieldname, filename, encoding, mimetype)

    if (mimetype !== 'image/jpeg' && mimetype !== 'image/png') {
      return res.status(400).json({
        error: '❌ Wrong file type submitted'
      })
    }

    const imageExtension = filename.split('.')[filename.split('.').length - 1]

    imageFileName = `${Math.round(
      Math.random() * 1000000000000
    )}.${imageExtension}`

    const filepath = path.join(os.tmpdir(), imageFileName)

    imageToBeUploaded = {
      filepath,
      mimetype
    }

    file.pipe(fs.createWriteStream(filepath))

  })


  busboy.on('finish', () => {
    admin
      .storage()
      .bucket(config.storageBucket)
      .upload(imageToBeUploaded.filpath, {
        resumable: false,
        metadata: {
          metadata: {
            contentType: imageToBeUploaded.mimetype,
          },
        },
      })
      .then(() => {
        const imageUrl = `https://firebasestorage.googleapis.com/v0/b/${config.storageBucket}/o/${imageFileName}?alt=media`
        return db.doc(`/users/${req.user.handle}`).update({
          imageUrl
        })
      })
      .then(() => {
        return res.json({
          message: '✅ Image uploaded successfully'
        })
      })
      .catch((err) => {
        console.error(err)
        return res.status(500).json({
          error: err.code
        })
      })
  })
  busboy.end(req.rawBody)
}