Installing Node.js and Setting up Visual Studio Code

The tutorial begins by guiding users through the installation of Node.js, suggesting a Google search for "node.js download" and providing a link in the description for convenience. Visual Studio Code (VS Code) is recommended as the code editor due to its integrated command prompt. The process includes downloading Node.js (version 8.11.3 LTS is mentioned), installing it, creating a new folder (e.g., "node.js tutorial"), opening it in VS Code, creating a new file (e.g., "app.js"), and writing a simple JavaScript program to test the installation (console.log("Hello world from node.js")).

Running Code using the Terminal

The tutorial demonstrates running the Node.js code using both the integrated terminal in VS Code and the standard command prompt. Steps for accessing and configuring the integrated terminal in VS Code are provided, including selecting the default shell (Command Prompt is preferred over PowerShell). Running the code involves navigating to the project directory using the cd command and then executing the command node app.js. The tutorial emphasizes that either method (integrated terminal or standard command prompt) is acceptable.

Understanding Node Modules

The concept of Node modules is explained. A Node module is described as a JavaScript file that helps separate concerns within an application. The tutorial shows how to create a new module ("tutorial.js"), define a function (e.g., sum), export it using module.exports, and then import and use it in the main "app.js" file using the require function. Multiple exports from a module are also demonstrated, using both individual module.exports properties and an object literal for cleaner syntax. Examples include exporting a function, a variable (pi), and a class (SomeMathObject).

Working with the Events Module

The tutorial introduces the Events module, specifically the EventEmitter class. It explains event-driven programming in Node.js. The process involves requiring the Events module (const EventEmitter = require('events');), creating an EventEmitter instance, attaching a listener using the on method, and emitting an event using the emit method. The tutorial also shows how to pass parameters to event listeners and demonstrates extending a custom class (e.g., Person) from the EventEmitter class to create event-driven objects.

Utilizing the Readline Module

The readline module is introduced, which enables prompting the user for input and getting responses. The tutorial shows creating a readline interface, asking questions using the question method, and handling user input within a callback function. The importance of trimming user input and closing the readline interface using rl.close() is highlighted. Event listeners are added to handle the close event (signaling a correct answer) and the line event (for continuous prompting until a correct answer is received).

File System Module: Working with Files

The tutorial covers the file system module (fs), demonstrating how to create files (fs.writeFile), read files (fs.readFile), rename files (fs.rename), append data to files (fs.appendFile), and delete files (fs.unlink). The importance of specifying encoding (e.g., 'utf-8') when reading files is emphasized. Error handling using callback functions is shown throughout the examples.

File System Module: Working with Folders

This section expands on the file system module to demonstrate folder manipulation. It shows how to create folders (fs.mkdir), delete folders (fs.rm), create files within folders, and handle the error of trying to delete a non-empty folder. The tutorial explains the use of relative paths (e.g., ./tutorial/example.txt) and demonstrates using fs.readdir to get a list of files in a folder, iterating through them, and deleting them individually.

Readable and Writable Streams

The tutorial introduces readable and writable streams for efficient data handling. It explains how streams read and write data in chunks, improving performance compared to loading entire files into memory at once. Examples are given of creating a readable stream (fs.createReadStream), listening for the 'data' event, and using a writable stream (fs.createWriteStream) to write data to a new file chunk by chunk. The advantages of streams, especially when dealing with large files, are highlighted.

Pipes and Pipe Chaining

The concept of pipes (readStream.pipe(writeStream)) is introduced as a simplified way to connect a readable stream (source) to a writable stream (destination). Pipe chaining is demonstrated, involving a transform stream (e.g., using the zlib module for compression/decompression) to manipulate data flowing between streams. Examples show compressing a file using zlib.createGzip() and decompressing it using zlib.createGunzip().

Creating an HTTP Server

The tutorial demonstrates creating a basic HTTP server using the http module. It shows how to create a server using http.createServer, handle requests and send responses using the request and response objects (res.write and res.end), and listen on a specific port (e.g., 3000) using server.listen. Handling requests to different routes (based on req.url) is also covered.

Serving Static Files with the HTTP Module

The tutorial shows how to serve static files (HTML, JSON, images) using the http and fs modules. It covers creating readable streams for files, setting response headers (res.writeHead) to specify content type, and piping the readable stream to the response object. Different content types (text/html, application/json, image/png) are used for different file types.

Creating and Using a `package.json` File

This section details the creation and purpose of the package.json file, which holds metadata for a Node.js project (name, version, description, etc.). The process of initializing a package.json file using npm init (and using the -y flag to skip interactive prompts) is shown.

Installing and Using Node Packages with npm

The tutorial explains how to install and use external packages using npm. It demonstrates searching for packages on npmjs.com, installing a package (e.g., lodash) using npm install lodash, and then requiring and using the installed package in your application (const _ = require('lodash');). Uninstalling a package using npm uninstall lodash is also shown.

Understanding Semantic Versioning

Semantic versioning (SemVer) is explained, focusing on the meaning of major, minor, and patch version numbers (e.g., 4.17.11). The tutorial describes how these numbers indicate the type of changes in a package update (bug fixes, new features, breaking changes). The use of the caret (^) and tilde (~) symbols in package versions within package.json to control update behavior is discussed.

Setting up an Express Server

This section introduces Express.js as a web framework for Node.js. It demonstrates installing Express (npm install express), creating a basic Express application (using the Express function), defining a route using app.get, sending a response (res.send), and listening on a port using app.listen.

Working with HTTP GET Requests: Query Strings and Route Parameters

The tutorial expands on Express routing, showing how to handle different routes (e.g., /, /example), access route parameters (using req.params), and access query string parameters (using req.query). The differences between route parameters (required data) and query string parameters (optional data) are explained with examples.

Serving Static Files with Express

This section demonstrates a more efficient way to serve static files using Express.js's built-in middleware. The process involves using app.use(express.static(path.join(__dirname, 'static'))); to serve files from a specified directory (here, "static"). The use of `path.join` for constructing paths and the concept of aliasing the static directory (e.g., making it accessible through "public" even if the actual directory is "static") is explained.

Handling HTTP POST Requests

The tutorial explains how to handle HTTP POST requests in Express.js using the body-parser middleware to parse form data. The process includes installing body-parser (npm install body-parser), using it as middleware (app.use(bodyParser.urlencoded({ extended: false }));), defining a POST route (app.post('/'...)), and accessing the parsed form data in req.body. The tutorial highlights that this is essential for handling data submitted via HTML forms.

Handling JSON Data with Express and Body Parser

This section focuses on handling JSON data using Express.js and body-parser. The tutorial shows how to modify an HTML form to submit JSON data using jQuery AJAX, configure the body-parser to handle JSON (app.use(bodyParser.json());), and send JSON responses using res.json().

Validating User Input with Joi

The tutorial introduces Joi for server-side input validation. It demonstrates installing Joi (npm install joi), creating a Joi schema to define validation rules (data types, minimum/maximum lengths, required fields, etc.), and using joi.validate() to check user input against the schema. Error handling and accessing validation results are covered.

Advanced Joi Validation: Nested Objects and Arrays

This section expands on Joi validation to handle more complex data structures. It shows how to create schemas for nested objects and arrays, using joi.object().keys() for objects and joi.array().items() for arrays (allowing specification of the schema for individual array elements). The tutorial demonstrates validation of an array of strings and an array of objects.

Using EJS Templates for Dynamic Web Pages

The tutorial introduces EJS (Embedded JavaScript) as a templating engine for creating dynamic web pages in Express.js. Setting up EJS (app.set('view engine', 'ejs');), creating EJS templates (files with the .ejs extension in the "views" directory), and rendering EJS templates using res.render() are covered. The tutorial also demonstrates passing data from the server to the EJS template and using EJS syntax (e.g., <%= %> for outputting data, <% %> for control flow) to dynamically generate HTML content. Examples include using loops (forEach) and conditionals (if) within the EJS templates.

Understanding and Creating Custom Middleware

The tutorial provides a detailed explanation of middleware in Express.js. It demonstrates creating custom middleware functions (functions with req, res, and next parameters) that execute between incoming requests and the route handler. The importance of calling next() to signal the completion of middleware processing is stressed. Using middleware for specific routes (app.use('/example', middlewareFunction)) and modifying the req and res objects within middleware are also explained.

Using the Express Router for Route Organization

This final section explains how to use the Express Router to organize routes into separate files, improving code management. It shows creating a router instance (const router = express.Router();), defining routes on the router (router.get('/', ...)), exporting the router (module.exports = router;), and using the router in the main application file (app.use('/people', peopleRouter);) to mount it at a specific base URL. The tutorial demonstrates adding middleware specific to a route within the router file.

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