Kod Refactoring

Refactor this [language] code for better readability, maintainability, and performance.

**Current code:**
```[language]
[code]
```

**Requirements:**
- Maintain exact same functionality (no behavior changes)
- Add proper error handling where missing
- Follow [pattern] design pattern
- Add TypeScript types if applicable
- Extract magic numbers/strings into constants
- Split large functions (>20 lines) into smaller ones

Show the refactored code with inline comments explaining each change.