A simple and functional stopwatch app built with React. This app allows you to start, stop, and reset a timer, with the time displayed in a clean MM:SS format. Built as a standalone React application using Create React App.

• ⏯️ Start, Stop, and Reset the timer
• 🕒 Displays time in MM:SS format
• ✅ Conditional message when timer is running
• 🧹 Interval cleanup using useEffect to avoid stacking
• ⚛️ Built with React Hooks (useState, useEffect)

12-stopwatch-timer/
├── public/
│   └── index.html
│
├── src/
│   ├── App.js
│   ├── index.js
│   └── App.css (optional / remove if not used)
│
├── package.json
└── README.md

• React.js (via Create React App)
• JavaScript (ES6+)
• React Hooks: useState, useEffect
• CSS (inline or optional App.css)
• Git & GitHub

1. Clone the repo

git clone https://github.com/abhishekdevelops/12-stopwatch-timer.git
cd 12-stopwatch-timer

2. Install dependencies

npm install

3. Start the development server

npm start

App will run at: http://localhost:3000

Click Start to begin the timer, Stop to pause, and Reset to return to 00:00.
A message appears below the timer while it’s actively running.

🔗 Live Demo: https://stopwatch-timer-psi.vercel.app/

• How to manage intervals in React
• How to prevent memory leaks using clearInterval and useEffect cleanup
• Formatting time from seconds to MM:SS
• Managing React component state in real-time apps

This app is part of my React Projects Portfolio.