uploading file with multer

I am a js-newbie and I am currently trying to use multer to upload some files. Here is my code:

let express = require('express');
let im = require('imagemagick');
let gm = require("gm").subClass({
    imageMagick: true
});
let multer  = require('multer');

let app = express();

let storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, '/uploads')
    },
    filename: function (req, file, cb) {
        cb(null, file.fieldname + '-' + Date.now())
    }
});
var upload = multer({storage: storage}).single('avatar');

app.post('/', function (req, res) {
    upload(req, res, function (err) {
        if (err instanceof multer.MulterError) {
            res.json({
                success: false,
                message: 'error during uploading'
            });
        } else if (err) {
            res.json({
                success: false,
                message: 'error during uploading'
            });
        }

        res.json({
            success: true,
            message: 'Image uploaded'
        });
    })
})

app.listen(3000);

When I send a post-req with a file (form-data), then I get a success message, however the folder with the file is not created:

post request

EDIT:

I managed to upload the file... I had to change the path of the uploads directory in the code like this:

let storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, './uploads/')
    },
    filename: function (req, file, cb) {
        cb(null, file.originalname)
    }
});

However the uploads directory hast to be created manually, it is not being created automatically if it is missing...how do I solve this problem?

You can check this issue out: https://github.com/expressjs/multer/issues/287

It says you should create a directory in 'destination' or as pre-requirements.