Understanding Express.js: Building Web Applications with Ease

Akash (codeguyakash)

What is Express.js?

Express.js is a web application framework for Node.js. If Node.js is the engine of your web server, think of Express.js as a streamlined toolkit that helps you build things quickly and easily. It handles the complexities of routing (mapping URLs to actions), templating (creating dynamic HTML pages), and much more, giving you a solid foundation for your web applications.

Why Use Express.js?

  1. Simplicity: Express offers a minimalist approach, giving you the freedom to structure your application the way you want.
  2. Flexibility: It works seamlessly with many other Node.js modules available, letting you pick the tools that best suit your project.
  3. Performance: Express.js is built on Node.js, giving you great performance and scalability for web apps.
  4. Popularity: Huge community support means lots of tutorials, help, and resources to learn from.

Core Concepts

  1. Routing: Express lets you define “routes” — these are patterns in URLs. For example
  2. This means, that when someone visits your website’s root (‘/’), they’ll see the text “Hello from the home page!”.
app.get('/', (req, res) => {
res.send('Hello from the home page!');
});
  1. Middleware: Think of middleware as functions that modify incoming requests or outgoing responses. They’re like checkpoints along the route of your application. Common uses:

i). Logging requests

ii). Authentication (checking if a user is logged in)

iii). Parsing data from forms

  1. Templating Engines: Express lets you plug in templating engines (like EJS, Pug, or Handlebars) These help you create dynamic HTML pages by filling in data on the fly.
const express = require('express');
const app = express();
const port = 3000;

// A route for the homepage
app.get('/', (req, res) => {
res.send('Hello, Express!');
});

// Start listening for requests
app.listen(port, () => {
console.log(`Example app listening at http://localhost:${port}`);
});

Explanation

  • We start by bringing in the ‘express’ module.
  • The app object is our main Express application.
  • We define a route for the homepage (‘/’). When someone visits this route, the function sends a text response.
  • Finally, we start the server listening on port 3000.

Next Steps

This is just a taste of Express.js! To learn more, explore:

  • Express.js Official Docs: The best source (https://expressjs.com/)
  • Building Routes for Different Request Types (GET, POST, etc.): Shape how your application handles user interactions.
  • Working with Templating Engines: Make your pages dynamic.
  • Using Middleware for Common Tasks: Add functionality at different points.

Sign up to discover human stories that deepen your understanding of the world.

Free

Distraction-free reading. No ads.

Organize your knowledge with lists and highlights.

Tell your story. Find your audience.

Membership

Read member-only stories

Support writers you read most

Earn money for your writing

Listen to audio narrations

Read offline with the Medium app

Akash (codeguyakash)
Akash (codeguyakash)

Written by Akash (codeguyakash)

Full Stack Developer with MERN Stack expertise, preparing to become an Expert SDE while building innovative web applications. https://codeguyakash.in

No responses yet

Write a response