Node.js Practice Projects

A collection of small Node.js projects built while learning backend development with Express, MongoDB, Socket.IO and Discord.js.

Project	What it does	Tech
url_shortner	URL shortener with login and click analytics	Express, MongoDB, JWT, EJS
realtime-chat-app	Real-time group chat	Express, Socket.IO
file-upload-app	File upload form	Express, Multer, EJS
discord_bot	Basic Discord bot with message and slash-command handling	Discord.js

Prerequisites

• Node.js v18+
• MongoDB running locally on mongodb://127.0.0.1:27017 (only for url_shortner)

Each project is independent. To run one:

cd <project-folder>
npm install
node index.js        # or: npm start (uses nodemon, where available)

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1. url_shortner

A URL shortening service where logged-in users can create short links and track how many times each one is clicked.

Features

• Sign up and log in (JWT-based authentication)
• Generate a short ID for any URL (using shortid)
• Redirect from a short link to the original URL (/url/:shortid)
• Visit history (timestamps) stored per link, with an analytics endpoint
• All /url routes are protected by a login-check middleware (reads the uid cookie)
• Server-rendered pages with EJS

Run

cd url_shortner
npm install
npm start

Runs on http://localhost:8001. Make sure MongoDB is running (database: short_url).

Routes

Method	Route	Description
GET	/	Home page
GET	/signup, /login	Auth pages
POST	/user	Create a new user
POST	/user/login	Log in
POST	/url	Create a short URL (login required)
GET	/url/:shortid	Redirect to the original URL and record the visit (login required)
GET	/url/analytics/:shortId	Total clicks and visit timestamps (login required)

Structure: controllers/, models/, routes/, middlewares/, services/, views/

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2. realtime-chat-app

A simple real-time chat app. Any message sent by one connected user is broadcast to everyone.

Features

• Real-time messaging with Socket.IO
• Static front end served by Express

Run

cd realtime-chat-app
npm install
node index.js

Open http://localhost:9000 in two or more browser tabs and send messages between them.

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3. file-upload-app

Demonstrates handling multipart/form-data file uploads with Multer.

Features

• HTML form (EJS) to pick and upload a file
• Files saved to the uploads/ folder (Multer gives them a random filename)
• Includes a second Multer config that keeps the original filename with a timestamp prefix (diskStorage), ready to swap in

Run

cd file-upload-app
npm install
mkdir uploads        # if it doesn't exist
npx nodemon index.js   # or: node index.js

Open http://localhost:8000, choose a file and click Upload.

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4. discord_bot

A starter Discord bot built with Discord.js v14.

Features

• Replies to messages in a channel (ignores other bots)
• create <url> message command (placeholder for connecting to the URL shortener)
• Slash command registration (/create) and a Pong!! interaction reply

Setup

1. Create an application and bot at the Discord Developer Portal.

2. Enable the Message Content Intent under the bot settings.

3. Invite the bot to your server using the OAuth2 URL generator.

4. Create a .env file in discord_bot/ (never commit it):

   DISCORD_TOKEN=your_bot_token
   CLIENT_ID=your_application_id
   

5. Load these values in the code via process.env.DISCORD_TOKEN and process.env.CLIENT_ID (for example with node --env-file=.env index.js on Node 20+, or the dotenv package).

Run

cd discord_bot
npm install
node command.js      # registers slash commands (run once)
npm start            # starts the bot

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Notes

These are learning projects, not production code. Known limitations:

• In url_shortner, /user/login returns the JWT as JSON; to use it with the browser pages, set it as the uid cookie (the res.cookie('uid', token) line is currently commented out).
• url_shortner stores passwords in plain text and needs hashing (e.g. bcrypt) before real use.
• Secrets (JWT secret, Discord token) should come from environment variables, not source code.