http

path

events

fs

A command-line tool for managing Node.js packages

A template engine for rendering HTML

A database management system for Node.js

Express.js provides a web application framework for Node.js, enabling routing, middleware, and easy handling of HTTP requests.

Middleware is a front-end framework

Middleware in Express is a function that processes requests and responses.

Middleware is a programming language

Middleware is a type of database

Execute 'npm install express.js' in your project directory.

Run 'npm install express' in your project directory.

Use 'npm add express' in your project folder.

Run 'npm start express' in your project directory.

fs.readFileAsync

fs.readFile

fs.readFileSync

fs.readSync

The 'fs' module is for creating web servers in Node.js.

The 'fs' module is used for file system operations in Node.js.

The 'fs' module is used for network operations in Node.js.

The 'fs' module handles database connections in Node.js.

app.get('/path', (req, res) => { res.send('Hello World!'); });

app.get('/anotherPath', (req, res) => { res.send('Hello World!'); });

app.route('/path', (req, res) => { res.send('Goodbye World!'); });

app.post('/path', (req, res) => { res.send('Hello World!'); });

3000

5000

8080

4000

nodemon

npm run

nodemon start

node

Set 'app.staticFiles('path/to/static/files');' to serve static files.

Implement 'app.serveStaticFiles('path/to/static/files');' to serve static files.

Use 'app.get('/static', express.static('path/to/static/files'));' to serve static files.

Use 'app.use(express.static("path/to/static/files"));' to serve static files.

To define routes in an Express application.

To mount middleware functions in an Express application.

To handle HTTP requests directly.

To serve static files in an Express application.

Ignore errors and continue processing requests.

Use an error-handling middleware function with four parameters (err, req, res, next) to handle errors in Express.

Use console.log to display errors in the terminal.

Return a generic error message without details.

The 'req' object sends the response, while the 'res' object receives the request.

The 'req' object is used for logging, and the 'res' object is for error handling.

The 'req' object manages database connections, while the 'res' object formats HTML.

The 'req' object handles the request data, while the 'res' object manages the response to the client.

const fs = require('fs'); fs.readFile('file.json', 'utf8', (data) => { console.log(data); });

const fs = require('fs'); fs.readFile('file.json', 'utf8', (err, data) => { if (err) throw err; const jsonData = JSON.parse(data); console.log(jsonData); });

const fs = require('fs'); fs.readFile('file.json', (data) => { console.log(data); });

const fs = require('fs'); fs.readFileSync('file.json');

To handle routing in Express applications.

To serve static files in Express applications.

To manage database connections in Express.

To parse incoming request bodies in Express applications.

app.delete('/route', (req, res) => { res.send('Response'); });

app.put('/route', (req, res) => { res.send('Response'); });

app.get('/route', (req, res) => { res.send('Response'); });

app.post('/route', (req, res) => { res.send('Response'); });

npm install nodemon -g

npm install --global nodemon

npm install nodemon

npm install -g nodemon

Use res.write({ key: 'value' });

Use res.send({ key: 'value' });

Use res.json({ key: 'value' });

Use res.sendFile({ key: 'value' });

The 'db.json' file is used for logging application errors.

The 'db.json' file is significant as it acts as a mock database for storing application data in JSON format.

The 'db.json' file serves as a configuration file for server settings.

The 'db.json' file is a template for generating HTML pages.