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NodeJS

Node.js is a runtime environment built on Chrome's V8 JavaScript engine, enabling server-side JavaScript development. It provides a non-blocking, event-driven architecture that allows developers to build scalable and efficient network applications. Node.js leverages the power of asynchronous programming, making it particularly suited for building real-time applications and handling a large number of concurrent connections.

Module 1: Introduction to Node.js

What is Node.js?

Node.js is an open-source, cross-platform, JavaScript runtime environment that executes JavaScript code outside a web browser.

// Load the HTTP library
var http = require('http');

// Create a server and send a response
http.createServer(function (request, response) {
  response.writeHead(200, {'Content-Type': 'text/plain'});
  response.end('Hello World\n');
}).listen(8080);

Understanding Node Package Manager (NPM)

NPM is a package manager for the JavaScript programming language. It is the default package manager for the JavaScript runtime environment Node.js.

// To install a package
npm install <package_name>

// To uninstall a package
npm uninstall <package_name>

Module 2: Introduction to Express.js

What is Express.js?

Express.js, or simply Express, is a back-end web application framework for Node.js.

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

// Respond with 'Hello World' for requests that hit our root '/'
app.get('/', function (req, res) {
  res.send('Hello World!');
});

// listen to port 3000 by default
app.listen(process.env.PORT || 3000);

Basic Routing with Express

Routing refers to how an application’s endpoints (URIs) respond to client requests.

// Respond with 'Hello World' for requests that hit our root '/'
app.get('/', function (req, res) {
  res.send('Hello World!');
});

// Respond to POST request on the root route ('/'), the application’s home page
app.post('/', function (req, res) {
  res.send('Got a POST request');
});

Module 3: Building RESTful APIs with Express.js

Introduction to RESTful APIs

A RESTful API is an architectural style for an application program interface (API) that uses HTTP requests to access and use data.

app.get('/api/items', (req, res) => {
  // Return some items
});
app.post('/api/items', (req, res) => {
  // Create a new item
});

Working with JSON

JSON (JavaScript Object Notation) is a popular data format with diverse uses in data manipulation and information sending/receiving in Node.js

app.get('/', function (req, res) {
  res.json({ message: 'Welcome to our API!' });
});

Module 4: Express Middleware

Understanding Middleware

Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle.

app.use(function (req, res, next) {
  console.log('Time:', Date.now())
  next()
})

Using Built-in Middleware

Express has a few important built-in middleware functions: json(), urlencoded(), static().

app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(express.static('public'));