Node.js

Free, open-source, cross-platform JavaScript runtime environment that lets developers create servers, web apps, command line tools and scripts.

Álvaro José Agámez Licha

Senior Software Engineer

https://github.com/aagamezl

https://x.com/aagamezl

The backend is the server-side part of a software application that handles data processing, business logic, and database interactions. It runs on remote servers, processes requests from the frontend (client side), and sends back appropriate responses.

What is Backend?

Hypertext Transfer Protocol (HTTP) is the foundation of web communication, defining how clients (browsers) and servers exchange requests and responses.

Key HTTP Methods (Verbs):

GET: Fetch data (e.g., loading a webpage).
POST: Submit new data (e.g., form submission).
PATCH/PUT: Update existing data.
DELETE:Remove data.

HTTP & REST Basics

To understand how HTTP messages work, we'll look at HTTP/1.1 messages:

HTTP & REST Basics

The following table lists HTTP request methods and their categorization in terms of safety, cacheability, and idempotency.

HTTP Request Methods

Method	Safe	Idempotent	Cacheable
GET	Yes	Yes	Yes
HEAD	Yes	Yes	Yes
OPTIONS	Yes	Yes	No
TRACE	Yes	Yes	No
PUT	No	Yes	No
DELETE	No	Yes	No
POST	No	No	Conditional*
PATCH	No	No	Conditional*
CONNECT	No	No	No

HTTP Response Status Codes

HTTP response status codes indicate whether a specific HTTP request has been successfully completed. Responses are grouped in five classes:

Informational responses (100 – 199)
Successful responses (200 – 299)
Redirection messages (300 – 399)
Client error responses (400 – 499)
Server error responses (500 – 599)

Informational Responses (1xx)

"Hold on, I’m thinking…" 🤔 (Server’s still loading, like your WiFi in a basement).

"Mission accomplished! 🎉 (rare like a perfect avocado in Europe 🥑)"

Successful Responses (2xx)

Oops, wrong address. Try this link. 🏃‍♂️💨" (The internet’s way of ghosting you to a new URL).

Redirection Messages (3xx)

"You had ONE job…" 😤 (you messed up, I can't believe it).

Client Error Responses (4xx)

"My bad, I’ll just… crash 💥" (server’s on strike. Blame the intern).

Server Error Responses (5xx)

HTTP Status Codes: The Drama Edition 🎭

Code	Name	Meme Description
200	OK	Everything worked!. (rare like a perfect avocado in Europe 🥑)
201	Created	New resource born! Name it wisely
204	No Content	Success! So clean and empty... like my desk on New Year's Day! 🧹💫
400	Bad Request	You sent garbage. The server's judging you
401	Unauthorized	Oops! Did you forget your keys again? 🔑 Time for a coffee break while you reset your password! ☕😊
403	Forbidden	You shall not pass! 🧙‍♂️ (Even if you brought coffee
404	Not Found	Whoops! This page went on vacation! 🏖️ Maybe try the homepage instead? 🏠💡
405	Method Not Allowed	Nope. Try again, hacker boi
500	Internal Server Error	The server's on strike. (Blame the intern)
502	Bad Gateway	The backend is ghosting us
503	Service Unavailable	Server's taking a nap

Node.js is a runtime environment that allows you to run JavaScript code outside of a browser.

It uses the V8 JavaScript engine, the same engine that powers Google Chrome.

What Is Node.js?

npm is the world's largest software registry. Open source developers from every continent use npm to share and borrow packages, and many organizations use npm to manage private development as well.

npm consists of three distinct components:

The website.
The Command Line Interface (CLI).
The registry.

NPM - Build Amazing Things

Meaningful names for variables, constants and functions
Always add the .gitignore
Give some love to your code, companies care about code quality
Blank lines are free, use them to separate your logic blocks
Use 2 spaces for indentation
Add comments to your code for why not what

Let's Care About Quality

You cheat yourself
Job interviews don’t allow AI
Struggle teaches you valuable skills
You’ll build a false sense of confidence
You're not really learning
It's really quite obvious

Let's Avoid Using Any LLM

Every time you use an LLM unnecessarily, a puppy dies.

Coding Time

Starting A Node.js Project

# Create a Project Folder
mkdir my-node-project
cd my-node-project

# Initialize the Project
npm init -y

# Create an Entry File
touch index.js

# Write Basic Code in index.js
console.log('Hello from Node.js!');

# Run Your App
node index.js

{
  "name": "your-project-name",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
  "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

Node.js

What is Backend?

HTTP & REST Basics

HTTP & REST Basics

HTTP Request Methods

HTTP Response Status Codes

Informational Responses (1xx)

Successful Responses (2xx)

Redirection Messages (3xx)

Client Error Responses (4xx)

Server Error Responses (5xx)

HTTP Status Codes: The Drama Edition 🎭

What Is Node.js?

NPM - Build Amazing Things

Let's Care About Quality

Let's Avoid Using Any LLM

Let's Avoid Using Any LLM

Every time you use an LLM unnecessarily, a puppy dies.

Coding Time

Starting A Node.js Project

Anatomy Of package.json

HyF Node.js Week 01

HyF Node.js Week 01

Alvaro Agamez

Node.js

What is Backend?

HTTP & REST Basics

HTTP & REST Basics

HTTP Request Methods

HTTP Response Status Codes

Informational Responses (1xx)

Successful Responses (2xx)

Redirection Messages (3xx)

Client Error Responses (4xx)

Server Error Responses (5xx)

HTTP Status Codes: The Drama Edition 🎭

What Is Node.js?

NPM - Build Amazing Things

Let's Care About Quality

Let's Avoid Using Any LLM

Let's Avoid Using Any LLM

Every time you use an LLM unnecessarily, a puppy dies.

Coding Time

Starting A Node.js Project

Anatomy Of package.json

HyF Node.js Week 01

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