NIM Game (MERN)

This workspace contains a prototype MERN application for playing the two-player NIM game in real-time using Socket.IO.

Folders:

• backend — Express + Socket.IO server (in-memory game rooms)
• frontend — Vite + React client

Quick Start (Local Development)

Option 1: Frontend Only (Recommended for quick testing)

The frontend can run in local two-player mode without requiring the backend:

cd frontend
npm install
npm run dev

This will start the Vite development server (usually on http://localhost:5173). Both players can play from the same device/browser.

Option 2: Full Stack (Frontend + Backend)

For real-time multiplayer with separate devices:

Start the backend:

cd backend
npm install
npm run dev

This starts the Express + Socket.IO server on port 4000.

Start the frontend:

cd frontend
npm install
npm run dev

Production Build

To build the frontend for production:

cd frontend
npm install
npm run build
npm run preview

Deploying to Vercel

This repository is prepared to deploy the static frontend to Vercel and includes a simple serverless health endpoint at /api/health.

Key points:

• The frontend (Vite) is built from the frontend/ folder. Vercel will run npm run build in frontend and publish the output.
• A minimal serverless endpoint is available at /api/health (see api/health.js).
• The current backend (backend/index.js) runs an Express + Socket.IO server which requires a long-lived WebSocket server. Vercel's serverless functions are not suitable for hosting a Socket.IO server (they do not support long-lived WebSocket servers reliably).

Recommended options for real-time backend:

1. Deploy the existing Express + Socket.IO server to a platform that supports long-lived sockets (Render, Fly.io, a VPS, Railway). Then point the frontend to that server's URL.
2. Replace socket-based realtime with a serverless-friendly realtime product (Pusher, Supabase Realtime, Ably) and update frontend to use that client.

How to deploy the frontend to Vercel (brief):

1. Sign in to Vercel and import the repository.
2. In the project settings, set the Root Directory to the repository root. The included vercel.json routes static files from frontend and provides /api endpoints.
3. Ensure the Build Command is npm run build --prefix frontend and the Output Directory is frontend/dist if Vercel asks.

If you want, I can:

• Add an example of switching the frontend to use an externally hosted Socket.IO server.
• Help create a small deployable backend on Render or Railway and wire it to the frontend.

Quick local build example

To build the frontend locally (what Vercel will run under the hood):

npm --prefix frontend install
npm --prefix frontend run build

What I changed

• Added vercel.json to configure Vercel's builds and routes.
• Added api/health.js as a tiny serverless health endpoint.
• Documented Socket.IO hosting recommendations.