app.js

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

const app = express();
const mongoDB = 'mongodb://localhost:27017/shopDB';
const productsRouter = require('./routing/products/index')

mongoose.connect(mongoDB, { useNewUrlParser: true });
mongoose.Promise = global.Promise;
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error:'));

app.use(bodyParser.json())
app.use(bodyParser.urlencoded({ extended: true }))

app.use(function (req, res, next) {
  res.setHeader('Access-Control-Allow-Origin', '*')
  res.setHeader(
    'Access-Control-Allow-Methods',
    'GET, POST, OPTIONS, PUT, PATCH, DELETE'
  )
  res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type')
  res.setHeader('Access-Control-Allow-Credentials', true)
  next()
})

app.use('/products', productsRouter);

var server = app.listen(8080, err => {
  if (err) {
    console.log('error', 'Error: ' + err)
  }
  console.log('Server is running on port: ' + server.address().port)
})