1. Introduction to Node.js

1. What is Node.js?

Node.js is an open-source, cross-platform runtime environment for executing JavaScript code outside of a web browser
It’s built on Chrome’s V8 JavaScript engine, which compiles JavaScript directly to machine code for fast execution
- In order to execute Javascript a web browser has (what we call) a Javascript engine
- This engine compiles or interprets the Javascript code on the page, and then executes it appropriately in the browser
Node.js was the first big push to allow Javascript to be ran outside the browser
Node.js is a runtime for Javascript, not a Javascript framework
- This means Node.js is just an environment that can execute Javascript
- It doesn’t natively provide any form of structure for building a specific application
- Instead frameworks like Express.js were created to make it easier to build a web backend with Node.js

Fun Fact: Other JavaScript Runtimes Exist! 🚀

Node.js is the most popular JavaScript runtime, but there are others too!
Deno:
- Created by Ryan Dahl, the original author of Node.js, as a “do-over” to fix design issues in Node.
- Built with security first (e.g., no access to the file system or network by default).
- Natively supports TypeScript out of the box, no additional setup needed.
Bun:
- A newer, high-performance runtime designed to be fast (think supercharged Node.js).
- Aims to be an all-in-one tool for developers, so it includes many common tools, reducing the need for multiple tools during development

Asynchronous and Event-driven:
- Node.js has built in, simple support for asynchronous programming
- Meaning operations like reading files, querying databases, and making API calls could be done simultaneously, instead of sequentially
- Due it’s non-blocking nature, Node.js is extremely efficient for I/O intensive tasks
- This means it can handle thousands of I/O based requests concurrently
Single-threaded with Event Loop:
- Node.js operates on a single thread but uses an event loop to manage concurrent requests
  - This means it can do multiple things “at once” but not in the way you would usually expect with a multi-threaded program
- It delegates heavy operations (like database queries) to background processes where they can continue to be executed in the background
- Then, while those run, the rest of the code can continue
NPM (Node Package Manager):
- Node.js comes with npm, the default package manager for Node.js
  - A package manager is a tool that helps a developer manage their external libraries (known as packages)
- Node.js, through npm has a huge ecosystem of packages just waiting for use
- npm makes it extremely easy to create new packages or add existing ones to your project
  - Using these premade packages can help you get your project off the ground quickly

There are tons of options when working with web development, you can create a web backend in almost every language (PHP, Ruby and Java used to be common). So why use Node.js?
Speed and Efficiency
- Node.js runs on the “Chrome V8” engine, which compiles Javascript to machine code for fast execution
- Asynchoronous I/O makes it able to handle high volumes of I/O heavy tasks (like database work or network requests) at once
Lots of support
- As silly as it is, Node.js is popular in part because everyone else is using it too
- With a large community, there are already lots of resources out there to help you learn and solve problems
- npm provides easy access to a huge volume of packages, which means the barrier to get up and running is even lower
Same language on the front and backend
- Using the same language everywhere means developers don’t have to spend the time learning and becoming comfortable with multiple languages
- Reduces the cognitive load for developers when switching from the front to the backend
- This increases development speed while (often times) lowering costs