app.js

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

const productsRoutes = require("./api/routes/products");
const ordersRoutes = require("./api/routes/orders");
const userRoutes = require("./api/routes/user");
mongoose.connect(
  "mongodb+srv://lavaraju:" +
    process.env.MONGO_ATLAS_PW +
    "@node-rest-shop-lxrf7.mongodb.net/test?retryWrites=true&w=majority",
  { useNewUrlParser: true, useUnifiedTopology: true }
);
mongoose.Promise = global.Promise;
mongoose.set("useCreateIndex", true);

app.use(morgan("dev")); // for showing status of the response
app.use("/uploads", express.static("uploads"));
app.use(bodyParser.urlencoded({ extended: false }));
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-Methods",
      "PUT",
      "POST",
      "PATCH",
      "DELETE",
      "GET"
    );
    return res.status(200).json({});
  }
  next();
});

app.use("/products", productsRoutes); //import the productsRoute
app.use("/orders", ordersRoutes);
app.use("/user", userRoutes);

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;