Express.js Tutorial: Building Web Applications and APIs with Node.js

Learn Express.js, a popular Node.js framework, with this comprehensive tutorial. This guide covers fundamental concepts, routing, middleware, handling HTTP requests, and building both simple and more complex web applications and APIs, suitable for both beginners and experienced Node.js developers.

Express.js Tutorial

This tutorial covers Express.js, a popular Node.js web framework, from basic to advanced concepts. It's designed for both beginners and experienced developers.

What is Express.js?

Express.js is a fast, minimal, and flexible Node.js web application framework. Think of it as a layer on top of Node.js that simplifies server management and routing. It provides powerful features for creating web and mobile applications.

Key Features of Express.js

  • Supports single-page, multi-page, and hybrid web applications.
  • Uses middleware to handle HTTP requests.
  • Defines a routing table to manage different actions based on HTTP methods (GET, POST, etc.) and URLs.
  • Dynamically renders HTML pages using templates.

Why Use Express.js?

  • Very fast I/O (Input/Output) performance.
  • Asynchronous and single-threaded architecture.
  • Provides a structure similar to the Model-View-Controller (MVC) pattern.
  • A robust API simplifies routing.

A Basic Express.js App

Here's a simple Express.js application that responds to requests on the root URL ("/"):

Basic Express.js App

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

app.get('/', function (req, res) {
    res.send('Welcome to JavaTpoint!');
});

var server = app.listen(8000, function () {
    var host = server.address().address;
    var port = server.address().port;
    console.log('Example app listening at http://%s:%s', host, port);
});

This code creates a simple server that listens on port 8000 and sends a "Welcome" message in response to GET requests to the root URL. You would run this using `node basic_express.js`.

Express.js Tutorial Outline

This tutorial covers the following topics:

  • Installing Express.js (on Windows and Linux)
  • Understanding the Request and Response objects
  • GET and POST methods
  • Routing
  • Cookie Management
  • File Uploads
  • Middleware
  • Scaffolding
  • Templating
  • Interview Questions (Node.js, AngularJS, JavaScript, jQuery, etc.)

Prerequisites & Audience

Basic knowledge of JavaScript and Node.js is recommended. This tutorial is suitable for both beginners and experienced developers.

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