CODE EXAMPLE FOR JAVASCRIPT

multer

<form action="/profile" method="post" enctype="multipart/form-data">
  <input type="file" name="avatar" />
</form>

-----Configer Multer -------
const multer = require("multer");
const path = require("path")
const storage = multer.diskStorage({
    destination(req, file, cb) {
        cb(null, 'public/uploads')
    },
    filename(req, file, cb) {
        console.log(path.extname, file.originalname)

        cb(null, `${file.fieldname}-${Date.now()}-${Math.round(Math.random()*1E9)}${path.extname(file.originalname)}`)
    }
})

const checkFileType = (file, cb) => {
    const fileType = /jpg|jpeg|png/
    const extname = fileType.test(path.extname(file.originalname).toLowerCase())
    const mimetype = fileType.test(file.mimetype)

    if (extname && mimetype) {
        return cb(null, true)
    } else {
        cb(new Error("Only Image Support!"), false)
    }
}

const upload = multer({
    storage,
    limits: {
        fileSize: 5e+6
    },
    fileFilter(req,file,cb){
        checkFileType(file,cb)
    }

})

app.post('/', upload.single('fild-name'), (req, res) => {
  res.send(`/${req.file.path}`)
})

//OR => For Error Handling
app.post('/', (req, res,next) => {
   upload(req, res, async (err) => {
        if (err) {
            return next(new Error("Server Error"))
        }
        const filePath = req.file.path
        console.log(req.body)
        let { error } = productSchema.validate(req.body)
        if (error) {
            fs.unlink(root + "/" + filePath, (err) => {
                if (err) {
                    return next(new Error("Server Error"))
                }
            })
            return next(error)
        }

        let { name, price, size, image } = req.body
        let document
        try {
            document = await ProductModel.create({
                name,
                price,
                size,
                image: filePath
            })
        } catch (err) {
            return next(err)
        }

        res.status(201).json(document)

        res.send({})
    })
})