How To Handle Global Connection of MongoDB in NodeJs?

Handling a global connection to MongoDB in a Node.js application is important for efficient resource management and performance optimization. By maintaining a single connection to the MongoDB database, you avoid the overhead of repeatedly establishing and closing connections, which can be resource-intensive and slow. This article will guide you through the steps to set up and manage a global MongoDB connection in a Node.js application.

Prerequisites

• MongoDB
• ExpressJs
• NodeJs
• JavaScript

Why Handle Global MongoDB Connections?

• Performance: Reusing a single connection pool improves performance by reducing the overhead of establishing new connections.
• Resource Management: Prevents unnecessary consumption of resources and potential memory leaks.
• Error Handling: Centralized connection management simplifies error handling and debugging.
• Scalability: Facilitates scaling by ensuring the connection pool is shared across multiple requests.

Managing a Global MongoDB Connection

To manage a global MongoDB connection, you should create a reusable connection pool that can be accessed from different parts of your application. We will cover how to implement this using both a custom module and a singleton pattern.

Steps to Setup Project

Step 1: Create a reactJS application by using this command

npx create-react-app DB

Step 2: Navigate to the project directory

cd DB

Step 3: Install the necessary packages/libraries in your project using the following commands.

npm install mongoose express

Project Structure

Dependencies

"dependencies": {
    "express": "^4.19.2",
    "mongodb": "^6.7.0"
  }

Example: Implementation to show handling global connection of Mongodb in NodeJs.

//db.js

const { MongoClient } = require("mongodb");

let dbInstance = null;

async function connect(url, dbName) {
    try {
        const client = new MongoClient(url);
        await client.connect();
        dbInstance = client.db(dbName);
        console.log("Connected to MongoDB");
    } catch (error) {
        console.error("Error connecting to MongoDB:", error);
        throw error;
    }
}

function getDBInstance() {
    if (!dbInstance) {
        throw new Error("Database not connected");
    }
    return dbInstance;
}

module.exports = { connect, getDBInstance };

// app.js

const express = require("express");
const { connect } = require("./db");

const app = express();

// Connect to MongoDB
const mongoUrl = "mongodb://localhost:27017";
const dbName = "your_database_name";
connect(mongoUrl, dbName);


app.listen(3000, () => {
    console.log("Server is running on port 3000");
});

Step to Run Application: Run the application using the following command from the root directory of the project

npm start

Output: Your project will be shown in the URL http://localhost:3000/