Heroku and multer

I made a webapp that lets you upload a file to the server using multer. It works like it should when the server is run locally, but when I deployed it on Heroku, it seems I ran into a 500 internal server error.

Has anyone dealt with this before?

What are the options?

Webapp is here: https://dupefinder.herokuapp.com/

Github repo is here: https://github.com/ExtDASH/herkodeploy

2018-09-19T19:38:48.310177+00:00 app[web.1]: POST /uploads 500 148 - 181.170 ms
2018-09-19T19:38:48.310830+00:00 app[web.1]: Error: ENOENT: no such file or directory, open 'uploads/csv1537385928295.csv'
2018-09-19T19:38:48.311255+00:00 heroku[router]: at=info method=POST path="/uploads" host=dupefinder.herokuapp.com request_id=ff1aaa34-f36c-49cf-bd4e-4a936fb48a2c fwd="24.52.32.175" dyno=web.1 connect=1ms service=188ms status=500 bytes=404 protocol=https

and here is the console error in the browser:

main.js:146 POST https://dupefinder.herokuapp.com/uploads 500 (Internal Server Error)
reader.onload @ main.js:146
load (async)
readFile @ main.js:131
invoker @ vue.js:2029
Vue.$emit @ vue.js:2538
click @ VBtn.ts:108
invoker @ vue.js:2029
fn._withTask.fn._withTask @ vue.js:1828

I'm using an XMLHttpRequest POST request:

readFile: function(){
        const input = document.querySelector('#myFile')
        const reader = new FileReader()
        reader.onload = function() {
            let csvfile = new Blob([reader.result], { type: 'text/csv' })
            app.uploadingFile = true

            const form = new FormData()
            let sendName = input.files[0].name.split(/\W+/g)

            form.append('Ncsv', csvfile, `${sendName[0]}.csv`)
            const xhr = new XMLHttpRequest()
            xhr.open('POST', '/uploads', true)
            xhr.onreadystatechange = function() {
                if(this.readyState == XMLHttpRequest.DONE && this.status == 200) {
                    form.delete('Ncsv')
                }
            }
            xhr.send(form)

        }
        reader.readAsText(input.files[0])

which goes to an app.post route in my server.js file:

const express = require('express')
const connect = require('connect')
const morgan = require('morgan')
const bodyParser = require('body-parser')
const mongoose = require('mongoose')
const fs = require('fs-extra')
const multer = require('multer')
const getRouter = require('./routes/ourNums')
const nFs = require('./fileSchema.js')
const namesRouter = require('./routes/namesRouter.js')
const computeRouter = require('./routes/computeRouter.js')

// const uploadRouter = require('./routes/uploadRouter') unused for now
const filesRouter = require('./routes/filesRouter')
const path = require('path')



const app = express()

var storage = multer.diskStorage({
destination: function (req, file, cb) {
    fs.ensureFile(file)
    .then(() => {
        console.log('done')
     }
    cb(null, __dirname+'/uploads')
},
filename: function (req, file, cb) {
    var newName = file.originalname.split(/\W+/g)
    var fullName = `${newName[0]}${Date.now()}.csv`
    cb(null, fullName)
},
})



var upload = multer({ storage: storage })

app.use(express.json({limit: '50mb'}))
app.use(bodyParser.urlencoded({extended: false}))
app.use(bodyParser.json())
app.use(bodyParser.json({ limit: '50mb' }))
app.use(morgan('tiny')) //watching for changes
// app.use(express.static(`${__dirname}/client/index.html`))

app.post('/uploads', upload.single('Ncsv'), function (req, res, next) {
var fileName = req.file.filename
nFs.create({
    name: fileName
})
.then(data => res.status(200).send())
.catch(e => {
    req.error = e
    console.log(e)
    next()
})
})

before, I didn't use fs for anything (and as you can see here, fs.ensureFile isn't doing anything to fix the 500 error), I just included it to begin with so I could play around with it. Running the server locally, this works. I click my upload button on my client and it sends whatever file i selected as a blob, runs it through multer, and creates the file in a /server/uploads/ directory

Edit: I just tried using multer.memoryStorage() and got the same 500 internal server error.