error-handling-patterns

name	error-handling-patterns
description	Error handling patterns and best practices. Use when implementing error handling, creating custom exceptions, or designing error responses.
license	Apache 2.0

Error Handling Patterns

When to Use This Skill

• Implementing error handling
• Creating custom exceptions
• Designing API error responses

Core Concepts

Custom Exceptions

class AppError extends Error {
  constructor(
    public code: string,
    message: string,
    public statusCode: number
  ) {
    super(message);
  }
}

class ValidationError extends AppError {
  constructor(message: string) {
    super('VALIDATION_ERROR', message, 400);
  }
}

class NotFoundError extends AppError {
  constructor(resource: string) {
    super('NOT_FOUND', `${resource} not found`, 404);
  }
}

Error Handling

try {
  await service.process(data);
} catch (error) {
  if (error instanceof ValidationError) {
    logger.warn('Validation failed', { error, data });
    throw error;
  }
  logger.error('Unexpected error', { error, data });
  throw new InternalServerError('Processing failed');
}

API Error Response

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid input data",
    "details": [
      { "field": "email", "message": "Invalid email format" }
    ]
  }
}

References

• Error Handling Guidelines