What is Express.js?

If you are learning backend development then you will hear one name again and again – Express.js. But What is it?, How it is used?, And how is this helpful for beginners? In this blog, you will get answers to all these questions.

This blog is for everyone who is new to backend programming and is searching for a framework like this which is easy, fast, and JavaScript-based.

So, let’s start and simplify your backend journey!

It is a web application framework which works on Node.js. In simple words, if Node is an engine then Express provides steering and controls to use it. Its main work is to create a server and handle HTTP requests like when a user visits a website, sends data, submits the form, or requests any API.

If you are creating a backend that requires login, signup, or data-saving features then you must use Express.

Why use Express.js?

Many people ask that if Node already provides JavaScript backend then why we should use Express.
Let’s understand some main reasons:

Simplified Server Creation – Creating server in Node is complex, Express makes this process easy.
Routing Made Easy – Handling different URLs for different functions becomes simple.
Middleware Support – You can easily add functionalities like logging, authentication, etc.
Faster Development – Less time for writing code.
Larger Community Support – Help and tools are available at every level.

Setting Up Express.js

If you want to use Express, then you have to first install Node. Then run this command in your terminal:

npm init -y
npm install express

Then create a server.js file and then write this basic server setup:

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

app.get('/', (req, res) => {
  res.send('Hello from Express.js!');
});

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

Now run node server.js and check it on localhost:3000 in your browser.

Key Concepts in Express.js

1. Routing – It means when we go to some specific URL then which code will run for that URL.
Example:

app.get('/about', (req, res) => {
  res.send('This is the About Page');
});

2. Middleware – It is a function which runs between request and response like logging, authentication, etc.

app.use((req, res, next) => {
  console.log('Middleware Started');
  next();
});

3. Request and Response Objects – In Express, there are req (request) and res (response) parameters in functions through which we can send and recieve data.

app.post('/login', (req, res) => {
  // req.body, req.params, req.query are used.
  res.send('Login Success');
});

Express.js Folder Structure

Structure of a good Express App looks like this:

project-name/
|-- node_modules/
|-- routes/
|   |-- users.js
|-- models/
|   |-- userModel.js
|-- controllers/
|   |-- userController.js
|-- server.js
|-- package.json

Using this structure the app becomes maintainable and scanable.

Connecting Express.js with MongoDB

If you are developing MERN Stack, then connecting Express and MongoDB is common using mongoose package:

npm install mongoose

Connection:

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/mydb', {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

Real Use Cases:

Creating RESTful APIs
Authentication Systems
Admin Panels Backend
Chat Applications Backend
Data Storage and Retrieval Systems

Projects you can build

To-Do List API
User Authentication App
Blogging Platform Backend
Real-time Chat Server
E-commerce Product API

You can use and easily implement POST, GET, PUT, DELETE methods while creating projects using Express.

Express.js vs Other Frameworks

1. Express vs Django:

Django is for Python whereas Express is for JavaScript.
Express is lightweight and Django is an opinionated framework.

2. Express vs Spring Boot:

Spring is Java-based, Express is JavaScript-based.
Express is simple, Spring is for enterprise level.

Conclusion

So, now you know that Express.js is a powerful and easy-to-learn backend framework that gives you the power to develop the whole backend using JavaScript.

If you are learning MERN Stack or developing a backend, then Express.js would be the best option for you. Practice more, create small APIs and slowly-slowly move to advanced level.

Express = Simplicity + Speed + JavaScript Magic

Share and help your fellow developers if you like the blog!🙌

Happy Coding and Keep Expressing with Express.js! 🚀

Express.js