I’m building a portfolio site with express and i’m trying to make a dashboard to add my works from the interface but i get some errors when i try to upload files. the ejs form is encoded in multipart/form-data

//this is how multer is set up
const storage = multer.diskStorage({
    destination: (req, file, cb) => {

      const workPath = `./data/works/${req.body.id}/`
  
      fs.access(workPath, (err) => {
        if (err) {
          // La directory non esiste la crea
          fs.mkdirSync(workPath, { recursive: true })
        }

        cb(null, workPath)
      })
    },

    filename: (req, file, cb) => {
      cb(null, file.originalname)
    }
})

this is the post request causing the error (i guess)
it’s made to add those three files in a folder and add data and their name to a json

router.post('/addwork', auth,

  upload.fields([
    { name: 'image', maxCount: 1 },
    { name: 'audio', maxCount: 1 },
    { name: 'file', maxCount: 1 }
  ]), 
  
  (req, res) => {
    //console.log(req.body)
    //console.log(req.files)
    console.log(validationResult(req))

    var newWorkInfo = req.body
    
    for (const key in req.files) {
      if (Object.hasOwnProperty.call(req.files, key)) {
        const filename = req.files[key][0].filename
        const field = req.files[key][0].fieldname
        //console.log(`${filename}, ${field}`)       
        newWorkInfo[field] = filename
      }
    }
    
    //console.log(newWorkInfo)
    const worksDbPath = "./data/works.db.json"
    let worksData = [];
    try {
      worksData = JSON.parse(fs.readFileSync(worksDbPath, 'utf8'));
    } catch (err) {
        console.log(err)
    }

    worksData.unshift(newWorkInfo)

    fs.writeFileSync(worksDbPath, JSON.stringify(worksData, null, 2))

    req.flash("authenticated", true)
    res.redirect("/admin/dashboard")
  })

this is the error i get when i try to submit the form

TypeError: path must be absolute or specify root to res.sendFile  at ...PortfolioSitenode_modulesexpresslibresponse.js:442:11

the script worked for some tasks, then started to not work anymore for some reason…