Benefits Application

• Stack: React, TypeScript, and [Vite/Next.js].
• Dependencies: Zustand, Immer, React Hook Form, Tailwind CSS, uuid.
• Prerequisites: Node.js (v22+) and npm/yarn.

Install & Run

# Install dependencies
npm install

# Start development server
npm run dev

# or

# Start production ready build
npm run start

The application will be available at http://localhost:5173 (or the next available port).

Architectural Decisions and Trade-Offs

1. Stack and Environment

• Custom Setup (TypeScript): I opted to use a clean React/TypeScript setup instead of the provided JavaScript starter files. This was a deliberate choice to ensure type safety, code robustness, and better long-term maintainability.
• Styling (Tailwind CSS): Tailwind CSS was chosen as a trade-off to minimize time spent on writing custom CSS.

2. State and Data Integrity

• Zustand + Immer + Normalization: State management utilizes Zustand with the Immer middleware. I implemented a normalized data structure (separate employees and dependents dictionaries linked by IDs) to ensure data consistency and efficient updates.
• Persistence: State persistence is achieved efficiently using the Zustand persist middleware integrated with localStorage.
• IDs: Unique IDs are generated using the uuid package to ensure production-level data integrity during CRUD operations.

Financial Integrity (Critical Trade-Off)

• Floating-Point Risk: The calculation logic involving payroll data is susceptible to IEEE 754 floating-point errors inherent to native JavaScript numbers.
• Mitigation: In a production environment, I would integrate a dedicated financial library, such as decimal.js or big.js, to ensure all calculations are performed with guaranteed precision. This is a crucial architectural decision to prevent errors in payroll data.