Claude Code

git status
claude --permission-mode plan

Prompt to Claude in Plan mode:

We are adding a simple canteen pre-order flow.
Do not edit files yet.
First inspect these files:
- package.json
- src/App.jsx
- src/pages/Menu.jsx
- src/lib/orders.js
- src/lib/menu.js

Then propose a plan for the smallest working change that lets a student select one menu item and create a pending order.
Constraints:
- Keep existing component style.
- No backend yet.
- Store orders in localStorage through src/lib/orders.js.
- Include any test or manual check I should run.
Reference the exact files you plan to change.

Before plan:
1. Add order management.
2. Update the menu UI.
3. Improve styling.
4. Add storage and tests if needed.

After editing with Ctrl+G:
1. In src/lib/orders.js, implement getOrders() and createOrder(item) using localStorage key "canteen_orders".
2. In src/pages/Menu.jsx, add a button beside each item that calls createOrder(item).
3. In src/pages/Menu.jsx, show "Order saved" after a successful click.
4. Do not add new dependencies.
5. Do not change routing, package.json, or src/lib/menu.js.
6. Manual check: run the app, click Order on Poha, refresh, and confirm getOrders() still returns the saved order.

// src/lib/orders.js
const STORAGE_KEY = "canteen_orders";

export function getOrders() {
  const saved = localStorage.getItem(STORAGE_KEY);
  return saved ? JSON.parse(saved) : [];
}

export function createOrder(item) {
  const order = {
    id: crypto.randomUUID(),
    itemId: item.id,
    itemName: item.name,
    price: item.price,
    status: "pending",
    createdAt: new Date().toISOString()
  };

  const orders = [...getOrders(), order];
  localStorage.setItem(STORAGE_KEY, JSON.stringify(orders));
  return order;
}

git status
git branch --show-current
git diff --stat
git diff

File: CLAUDE.md
Project: FestSplit

Commands:
- npm test
- npm run lint
- npm run build

Conventions:
- Use TypeScript for all app logic.
- Keep money amounts in paise internally.
- Display rupees only at the UI boundary.
- Do not read or modify .env files.

Architecture:
- src/lib contains pure calculation helpers.
- src/components contains React UI components.
- Tests live next to the file as *.test.ts.

File: .claude/settings.json
{
  "permissions": {
    "deny": [
      "Read(./.env)",
      "Read(./.env.*)"
    ]
  }
}

Before: src/lib/split.ts
export function splitAmount(totalRupees: number, people: number): number[] {
  const share = totalRupees / people;
  return Array.from({ length: people }, () => share);
}

After: src/lib/split.ts
export function splitAmountPaise(totalPaise: number, people: number): number[] {
  if (!Number.isInteger(totalPaise) || totalPaise < 0) {
    throw new Error("totalPaise must be a non-negative integer");
  }

  if (!Number.isInteger(people) || people <= 0) {
    throw new Error("people must be a positive integer");
  }

  const baseShare = Math.floor(totalPaise / people);
  const remainder = totalPaise % people;

  return Array.from({ length: people }, (_, index) => {
    return index < remainder ? baseShare + 1 : baseShare;
  });
}

After: src/lib/split.test.ts
import { describe, expect, it } from "vitest";
import { splitAmountPaise } from "./split";

describe("splitAmountPaise", () => {
  it("splits an amount evenly", () => {
    expect(splitAmountPaise(9000, 3)).toEqual([3000, 3000, 3000]);
  });

  it("distributes remaining paise without losing money", () => {
    expect(splitAmountPaise(10000, 3)).toEqual([3334, 3333, 3333]);
  });

  it("rejects invalid people count", () => {
    expect(() => splitAmountPaise(10000, 0)).toThrow("people");
  });
});

Commands:
git diff -- src/lib/split.ts src/lib/split.test.ts

npm test
npm run lint
npm run build

Focused prompt to Claude Code:
The command npm test fails after the splitAmountPaise change.
Only inspect src/lib/split.ts and src/lib/split.test.ts.
Keep money in paise internally.
Explain the cause first, then propose the smallest fix.

git status
git diff
git log --oneline -5

# Claude Code project context

Project: UPI Expense Splitter for college fest teams.

Stack:
- Client: React in client/
- Server: Node and Express in server/
- Data: local JSON storage for hackathon demo

Commands:
- Install root dependencies: npm install
- Start dev server: npm run dev
- Run client build: npm run build
- Run tests if present: npm test

Conventions:
- Keep UI text simple for Indian college users.
- Amounts are stored in rupees as numbers.
- Do not add paid services or external APIs unless asked.
- Do not read or modify .env files.
- For multi-file changes, propose a plan first.

Review checklist:
- Run npm run build before final commit.
- Check git diff before committing.
- Mention any untested area in the commit or PR notes.

mkdir -p .claude
cat > .claude/settings.json <<'EOF'
{
  "permissions": {
    "deny": [
      "Read(./.env)",
      "Read(./.env.*)"
    ]
  }
}
EOF

cat > .gitignore <<'EOF'
.env
.env.*
node_modules/
dist/
build/
.claude/settings.local.json
EOF

git status

git diff -- CLAUDE.md .claude/settings.json .gitignore
npm run build

# In Claude Code, run local review:
/code-review

# Then commit:
git add CLAUDE.md .claude/settings.json .gitignore server/routes/expenses.js client/src/pages/GroupSummary.jsx
git commit -m "Add reviewed CSV export for expense summaries"
git status

git remote -v
git push origin main