Express.js Tutorial


Express.js is a minimal and flexiable backend web application framework for Node.js. It was created by TJ Holowaychuk in 2010. It is designed for building API's, single-page applications, or full-stack web applications. Express.js is to handle HTTP requests and responses.

Key Features of Express.js

  • Middleware Support : Middleware functions are executed during the lifecycle of a request-response cycle.
  • Routing : Expres.jss provides robust routing for managing different URL endpoints
  • Template Engines : Express.js provides a variety of template engines like EJS, Pug, or Handlebars to render HTML pages.
  • Error Handling : Express.js provides robust error-handling features that allow developers handle errors and respond to errors effectively.
  • API Development : A lightweight framework for building RESTful APIs and web services.

Let's look at a basic Express.js app

index.js 
const express = require('express');
const app = express();
const PORT = 5000;

// Define a route
app.get('/', (req, res) => {
    res.send('Welcome to Express.js!');
});

// Start the server and listen on the specified port
app.listen(PORT, () => {
    console.log(`Server is running on http:// localhost:${PORT}`);
});

Run the server using the command given below.

D:\my-app>node index.js
Output Express setup project output

Why Use Express.js

  • Fast and Lightweight
  • Flexible and Minimalistic
  • Middleware Support
  • Robust Routing
  • Speed and Simplicity
  • Extensible Ecosystem
  • Compatibility

Prerequisites to Learn Express.js

  • JavaScript
  • Node.js Fundamentals
  • NPM
  • Understanding of HTTP & REST
  • Familiarity with JSON
  • Command Line Basics

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