Let’s Initialize Node.js (express) + MongoDB (mongoose)

3 min readAug 10, 2023

I write this story because I want to use it as a template in the future and share how I use Node.js with MongoDB. And for those who visit this stroy by accident.

My Code: https://github.com/panat54083/Medium_Node.js-MongoDB

Initial the backend with node.js + mongoDB

1- init node.js

Create a new directory for your project and navigate into it.

Run the following command in the terminal to initialize package.json

npm init -y

2- install the mongodb module in the terminal

npm i express mongoose

3- set up a server

create server.js file in your root directory

// server.js

const express = require('express');
const app = express();
const port = 3000;

app.listen(port, () => {
  console.log(`Server is listening on port ${port}`);
});

Optional: try to run node server.js . If it can run perfectly, then go to the next step.

4- set up mongodb

create db.js file in your root directory.

// db.js

const mongoose = require('mongoose');
const dbURI = 'mongodb://localhost:27017/your-database-name';

mongoose.connect(dbURI, { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => console.log('Connected to MongoDB'))
  .catch(error => console.error('MongoDB connection error:', error));

update server.js file. We need to import db.js .

// server.js

require("./db.js")

// ... other code

Optional 1: try to run node server.js . If there is a MongoDB connection error, try to change localhost to 0.0.0.0 or 127.0.0.1.
Optional 2: I used to get some trouble but I forgot about it but I fixed by downloading MongoDB Community Server .

Initial CRUD Operations

1- Create Model

create file named models for storing the MongoDB model.

I suppose I want to create the Customer Model.

// models/Customer.js

const mongoose = require("mongoose");

const customerSchema = new mongoose.Schema(
    {
        email: {
            type: String,
            required: "Email is required!",
        },
        name: {
            type: String,
            required: "Name is required!",
        },
        age: {
            type: Number,
        },
    },
    {
        timestamps: true,
    }
);

module.exports = mongoose.model("Customer", customerSchema);

update the db.js file

// db.js

// ...Other code

//Model Setup
require("./models/Customer")

2- Create Controller

create file named Controller for storing the MongoDB controller.

I want to create the register function for Customer.

// controllers/Customer.js

const mongoose = require("mongoose");
const Customer = mongoose.model("Customer");

// Controller function to register a new customer
exports.registerCustomer = async (req, res) => {
    try {
        const { email, name, age } = req.body;

        // Check if the customer already exists based on email
        const existingCustomer = await Customer.findOne({ email });
        if (existingCustomer) {
            return res.status(400).json({ message: "Customer already exists with this email." });
        }

        // Create a new customer instance
        const newCustomer = new Customer({
            email,
            name,
            age,
        });

        // Save the new customer to the database
        await newCustomer.save();

        res.status(201).json({ message: "Customer registered successfully.", customer: newCustomer });
    } catch (error) {
        console.error("Error registering customer:", error);
        res.status(500).json({ message: "Internal server error" });
    }
};

3- Create Router

create file named Routers for storing the MongoDB router.

// routes/Customer.js

const router = require("express").Router();
const customerController = require("../controllers/Customer"); // Import the customer controller

// Define route for registering a new customer
router.post("/register", customerController.registerCustomer);

module.exports = router;

update the server.js file

// server.js

require("./db")

const express = require('express');
const app = express();
const port = 3000;

// ------------------------------ Start -----------------------------

// Middleware to parse JSON and URL-encoded data
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

//Setup routes
app.use("/api", require("./routes/Customer"));

// ------------------------------ End -------------------------------

app.listen(port, () => {
  console.log(`Server is listening on port ${port}`);
});