在node.js中请求正文/文件是否为空

Question

I have quite issues with the requests in node.js. I have a router that put request router.put (basically, I want to make some changes on a data that I stored in MongoDB). I am storing three different things which are name, price, file(path of file) on the server, and I am storing the data on the physical hard drive.

I did not want to use patch because I could not succeed the upload file by itself.

In order to check the request.body dependencies empty or not, I am using Object.keys() , but I cannot apply the same thing to request.file

It gives this error:

TypeError: Cannot read property 'filename' of undefined

And this is part of my code: By the way, in my js file I have all dependencies & requirements like multer, body.parser

router.put('/:productId', checkAuth, upload.single('productImage'), (req, res, next) => {
const id = req.params.productId;
var imageName = "";

Product.findById(id)
    .exec()
    .then(docs => {
        if (Object.keys(req.file.filename).length > 0) {
            imageName = docs.productImage;
            fs.unlink(__rootdir + '\\public\\uploads\\' + imageName, function(err) {
                console.log(err);
                if (err && err.code == 'ENOENT') {
                    console.info("File does not exist, will not update");
                } else if (err) {
                    console.info("Error occurred while trying to update");
                } else {}
            });
        }
        return Product.findById( {_id: id}).exec();
    })
    .then(doc => {
        if (doc) {
            if (Object.keys(req.body.name).length === 0) {doc.name =  doct.name;}
            else {doc.name = req.body.name;}

            if (Object.keys(req.body.price).length === 0) {doc.price = doc.price }
            else { doc.price = req.body.price; }

            if (Object.keys(req.file.filename).length === 0) {doc.productImage = doc.productImage;}
            else {doc.productImage = req.file.filename}

            doc.save(err => {
                if (err) {
                    res.send(err);
                }
                res.status(200).json({
                    message: 'Product Updated',
                    request: {
                        type: 'GET',
                        url: 'http://localhost:3000//products/' + id
                    }
                });
            });
        }        
    });
 });

Added code part:

const express = require('express');
const router = express.Router();
const mongoose =  require('mongoose');
const multer = require('multer');
const checkAuth = require('../middleware/check-auth');

const bodyParser = require('body-parser');

router.use(bodyParser.urlencoded());
router.use(bodyParser.json());

const fs = require('fs');

Answer 1

I solved my problem.

Instead of using Object.keys(req.file.filename).length === 0 , I used typeof(req.file) !== "undefined" . Doing like this can identify the form-data (especially about file uploading) exist or not. (Basically, checks the upload area empty or not)