app.js

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

const productRoutes = require('./api/routes/products');
const orderRoutes = require('./api/routes/orders');

mongoose.connect(`mongodb+srv://Mary:${process.env.MONGO_ATLAS_PASSWORD}@shop-rest-api.sxnn0.mongodb.net/${process.env.DBNAME}?retryWrites=true&w=majority`, {
    useNewUrlParser: true,
    useUnifiedTopology: true
});

mongoose.Promise = global.Promise;

app.use(morgan('dev'));
app.use(bodyParser.urlencoded({
    extended: false //set to true if you want more complex body with rich data in it for urlencoded data
}));
app.use(bodyParser.json());

app.use((req, res, next) => {
    res.header('Access-Control-Allow-Origin', '*');
    res.header(
        'Access-Control-Allow-Headers', 
        'Origin, X-Requested-With, Content-Type, Accept, Authorization'
    );
    if (req.method === 'OPTIONS') {
        res.header('Access-Control-Allow-Method', 'PUT, POST, PATCH, DELETE, GET');
        return res.status(200).json({});
    }
    next();
});

app.use('/products', productRoutes);
app.use('/orders', orderRoutes);

app.use((req, res, next) => {
    const error = new Error('Not found');
    error.status = 404;
    next(error);
});

app.use((error, req, res, next) => {
    res.status(error.status || 500);
    res.json({
        error: {
            message: error.message
        }
    });
});

module.exports = app;