Upload file using angular2 and nodejs (express)

uploadFile.ts

// FRONTEND (angular2)
// product-form.compontent.html
<input type="file" (change)="fileChangeEvent($event)" placeholder="Upload file..." />
<button type="button" (click)="upload()">Upload</button>

// product-form.compontent.ts
import { Component, OnInit } from '@angular/core';
import { Http } from '@angular/http';

@Component({
  selector: 'product-form',
  templateUrl: './product-form.component.html',
  styleUrls: ['./product-form.component.css']
})

export class ProductFormComponent implements OnInit {
  filesToUpload: Array<File> = [];

  constructor(private http: Http) {}

  ngOnInit() {}

  upload() {
    const formData: any = new FormData();
    const files: Array<File> = this.filesToUpload;

    formData.append("uploads[]", files[0], files[0]['name']);
    
    this.http.post('http://localhost:3001/upload', formData)
      .map(files => files.json())
      .subscribe(files => console.log('files', files))
  }

  fileChangeEvent(fileInput: any) {
    this.filesToUpload = <Array<File>>fileInput.target.files;
    this.product.photo = fileInput.target.files[0]['name'];
  }

// BACKEND (anodejs - express)
// npm install express multer

var express = require('express');
var multer = require('multer');
var path = require('path');
var app = express();
var port = 3001;

// le dice a express que el directorio 'uploads', es estatico.
app.use(express.static(path.join(__dirname, 'uploads')));

// para CORN
app.use(function (req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
});

var storage = multer.diskStorage({
  // destino del fichero
  destination: function (req, file, cb) {
    cb(null, './uploads/')
  },
  // renombrar fichero
  filename: function (req, file, cb) {
    cb(null, file.originalname);
  }
});

var upload = multer({ storage: storage });

app.post("/upload", upload.array("uploads[]", 12), function (req, res) {
  console.log('files', req.files);
  res.send(req.files);
});

var server = app.listen(port, function () {
  console.log("Listening on port %s...", port);
});