Getting Started with Node.js

What is it all about?

• A Back-end framework for JavaScript
• It allows you to run JavaScript on the server
• It's a javaScript runtime (it is not a programming language)
• An extension to JavaScript
• Native JSON Support
• It's open source
• Back-end technology
• You can process multiple requests at the same time

Installing Node.js

Official Node.js Download link: https://nodejs.org/en/download/

• LTS (Long Term Support) - Recommended for Most Users
• Current - Latest features

Choose an IDE (Integrated Development Environment)

Bitesize definition of IDE from the BBC here.

Some examples of IDEs:

• Brackets
• Sublime Text
• Visual Studio Code
• Webstorm (not free)

NPM (Node Package Manager)

• An open-source package manager for Node.js created in 2009
• You can import and create your own packages
• A package contains all the files needed for a module
• package.json.The folder node_modules is where to find the modules

Creating a Simple Web Server

• A web server
• Import a package
• HTTP stands for Hyper Text Transfer Protocol
• List of Status codes: 200/ 300/ 400/ 500...
• MIME Types: Content type
• HTTP request methods (GET, HEAD, POST, PUT, DELETE ...)

Node.js API

• API is the acronym for Application Programming Interface
• Node.js comes with built-in packages and core modules
• Index: https://nodejs.org/docs/latest/api/
• To include a module, you can use require()
• File System is one example: const fs = require('fs');

Terminology

• CPU - Central Processing Unit - executes code, it's much faster than the RAM and the HD.
• RAM - Random Access Memory. Short-term memory
• HD - Hard drive. It reads the file. Long-term memory
• Synchronous - Program is halted until resources are available
• Asynchronous - The program continues executing and doesn't wait for resources to be available.
• Arrow notation - clean way to write a callback function
• Callback function - Prevents blocking, allows code to run
• Middleware functions - have access to the request object (req) and the response object (res). It allows isolated functionalities to interact

Frameworks

• Express.js
• Nest.js
• Koa.js
• Meteor.js

Running a script

From the terminal type in node <name_of_the_file.js>