# Error Handling Expert

> Expert in error handling patterns, exception management, error responses, logging, and error recovery strategies for React, Next.js, and NestJS applications. Use when implementing error handling, exception filters, error responses, error logging, or recovery strategies.

- Skill: `shipshitdev/error-handling-expert` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds add shipshitdev/error-handling-expert`
- Raw SKILL.md: https://api.skillmd.com/api/skills/shipshitdev/error-handling-expert/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: shipshitdev (https://skillmd.com/u/shipshitdev)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/shipshitdev/error-handling-expert

---


# Error Handling Expert Skill

## When to Use

- Implementing error handling
- Creating exception filters
- Designing error responses
- Setting up error logging
- Implementing error recovery
- Handling async errors
- Creating error boundaries
- Implementing retry logic

## Project Context Discovery

Before providing guidance:

1. Check `.agents/memory/` for project architecture and error patterns
2. Review existing exception filters
3. Check for error monitoring (Sentry, Rollbar)
4. Review logging libraries (Winston, Pino)

## Core Principles

### Error Types

**Application Errors:** 400, 401, 403, 404, 409, 422
**System Errors:** 500, 502, 503, 504

### Error Response Format

```typescript
{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Validation failed",
    "details": [...],
    "timestamp": "2025-01-01T00:00:00Z",
    "path": "/api/users",
    "requestId": "req-123456"
  }
}
```

## Quick Patterns

### NestJS Exception Filter

```typescript
@Catch()
export class AllExceptionsFilter implements ExceptionFilter {
  catch(exception: unknown, host: ArgumentsHost) {
    // Log, format, respond
  }
}
```

### React Error Boundary

```typescript
class ErrorBoundary extends React.Component {
  componentDidCatch(error, errorInfo) {
    // Log to monitoring
  }
}
```

### Retry with Backoff

```typescript
async function retryWithBackoff<T>(fn, maxRetries = 3): Promise<T>
```

## Best Practices

- User-friendly messages, no sensitive info
- Log all errors with context
- Integrate error monitoring (Sentry)
- Implement retry logic and circuit breakers
- Provide fallback values
- Test error cases

## Recovery Strategies

1. **Retry Logic** - Exponential backoff
2. **Circuit Breaker** - Prevent cascade failures
3. **Fallback Values** - Graceful degradation

---

**For complete exception filter implementations, custom exceptions, validation pipe setup, error boundaries, circuit breaker pattern, logging integration, and database/API error patterns, see:** `references/full-guide.md`