How to save file in node.js server?

Question

Node.js

I form data and send it like this

submitForm (newValue) {
 let FD = new FormData()
 FD.append('action', 'UPDATE')
 FD.append('params', JSON.stringify(OEWparams))
 if (this.oew_type === 'el_image') {
  newValue.forEach(function (item, index) {
   FD.append('p[' + index + '][0]', item.img)
   FD.append('p[' + index + '][1]', item.img_mini)
  })
 }
 for (let value of FD.values()) {
  console.log(value)
 }
 Api().post('settings', FD)
}

console

UPDATE

{"edit_type":"el","el_object":"5cad5b7f9439b91b342d3663","pixel_id":"5c7defa9f3eb9d0efcc4b5a9","el_type":"5c5e951ec3d902119834af69","value_type":"image","new_value":[],"startIndex":0}

File {uid: 1558322638902, name: "2018-lexus-lx570-116-1526419489.jpg", lastModified: 1550452912986, lastModifiedDate: Mon Feb 18 2019 11:21:52 GMT+1000 (Владивосток, стандартное время), webkitRelativePath: "", …}

File {name: "blob", lastModified: 1558322829055, lastModifiedDate: Mon May 20 2019 13:27:09 GMT+1000 (Владивосток, стандартное время), webkitRelativePath: "", size: 82204, …}

I read like this

const multer = require('multer');
const storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, '/tmp/my-uploads')
    },
    filename: function (req, file, cb) {
        cb(null, file.fieldname + '-' + Date.now())
    }
})

const upload = multer({ storage: storage }).single('p')

app.all('/settings', (req, res) => {
 var action = req.body.action;
 if (req.body.hasOwnProperty('params')) {
        if (typeof req.body.params === 'string') {
            req.body.params = JSON.parse(req.body.params);
        }
        if (req.body.params.hasOwnProperty('edit_type', 'value_type')) {
            if (req.body.params.edit_type === 'el' && req.body.params.value_type === 'image') {
                req.body.params.new_value = req.body.imgs
                upload(req, res, function (err) {
                    if (err instanceof multer.MulterError) {
                        // A Multer error occurred when uploading.
                        console.log(err)
                    } else if (err) {
                        // An unknown error occurred when uploading.
                        console.log(err)
                    }

                    // Everything went fine.
                })
            }
        }
    }		
})

But the files are not saved, what's the problem?