error-handling-expert

Included with Lifetime

$97 forever

Expert in error handling patterns, exception management, error responses, logging, and error recovery strategies for React, Next.js, and NestJS applications

Web Dev

What this skill does


# Error Handling Expert Skill

Expert in error handling patterns, exception management, error responses, logging, and error recovery strategies for React, Next.js, and NestJS applications.

## 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`

Files: 3

Size: 13.5 KB

Complexity: 32/100

Category: Web Dev

Source: https://github.com/shipshitdev/library/tree/main/bundles/backend/skills/error-handling-expert

Related in Web Dev

generating-lwc-components

Included

Lightning Web Components with PICKLES methodology and 165-point scoring. Use this skill when the user creates or edits LWC components, builds wire service patterns, or writes Jest tests for LWC. TRIGGER when: user creates/edits LWC components, touches lwc/**/*.js, .html, .css, .js-meta.xml files, or asks about wire service, SLDS, or Jest LWC tests. DO NOT TRIGGER when: Apex classes (use generating-apex), Aura components, or Visualforce.

Web Devscripts

tanstack-query

Included

Manage server state in React with TanStack Query v5. Set up queries with useQuery, mutations with useMutation, configure QueryClient caching strategies, implement optimistic updates, and handle infinite scroll with useInfiniteQuery. Use when: setting up data fetching in React projects, migrating from v4 to v5, or fixing object syntax required errors, query callbacks removed issues, cacheTime renamed to gcTime, isPending vs isLoading confusion, keepPreviousData removed problems.

Web Devscripts

document-processor-api

Included

Process documents with Nutrient DWS. Use when the user wants to generate PDFs from HTML or URLs, convert Office/images/PDFs, assemble or split packets, OCR scans, extract text/tables/key-value pairs, redact PII, watermark, sign, fill forms, optimize PDFs, or produce compliance outputs like PDF/A or PDF/UA. Triggers include convert to PDF, merge these PDFs, OCR this scan, extract tables, redact PII, sign this PDF, make this PDF/A, or linearize for web delivery.

Web Devscripts

nutrient-document-processing

Included

Web Devscripts

tanstack-query

Included

Manage server state in React with TanStack Query v5. Covers useMutationState, simplified optimistic updates, throwOnError, network mode (offline/PWA), and infiniteQueryOptions. Use when setting up data fetching, fixing v4→v5 migration errors (object syntax, gcTime, isPending, keepPreviousData), or debugging SSR/hydration issues with streaming server components.

Web Devscripts

accelint-nextjs-best-practices

Included

Next.js performance optimization and best practices. Use when writing Next.js code (App Router or Pages Router); implementing Server Components, Server Actions, or API routes; optimizing RSC serialization, data fetching, or server-side rendering; reviewing Next.js code for performance issues; fixing authentication in Server Actions; or implementing Suspense boundaries, parallel data fetching, or request deduplication.

Web Devscripts