error-handling

# Error Handling

Design resilient applications through intentional error handling strategies.

## Error Handling Philosophy

```
┌─────────────────────────────────────────────────────────────────┐
│                    Error Handling Goals                         │
├─────────────────┬─────────────────┬─────────────────────────────┤
│   Debuggable    │   Recoverable   │      User-Friendly          │
│ "What failed?"  │ "Can we retry?" │    "What should I do?"      │
├─────────────────┼─────────────────┼─────────────────────────────┤
│ Rich context    │ Retry logic     │ Clear, actionable messages  │
│ Stack traces    │ Fallbacks       │ Appropriate detail level    │
│ Correlation IDs │ Circuit breaker │ Recovery guidance           │
└─────────────────┴─────────────────┴─────────────────────────────┘
```

**Core principle:** Errors are data, not just exceptions. Design them intentionally.

## Quick Decision Guide

| Situation | Pattern | Reference |
|-----------|---------|-----------|
| Need typed error categories | Custom error classes | [error-patterns.md](references/error-patterns.md) |
| Want explicit error handling (no throws) | Result/Either type | [error-patterns.md](references/error-patterns.md) |
| React component might crash | Error boundary | [react-errors.md](references/react-errors.md) |
| API endpoint error response | Structured API errors | [api-errors.md](references/api-errors.md) |
| Network calls that might fail | Retry with backoff | [recovery-patterns.md](references/recovery-patterns.md) |
| Downstream service unreliable | Circuit breaker | [recovery-patterns.md](references/recovery-patterns.md) |
| Feature can work without dependency | Graceful degradation | [recovery-patterns.md](references/recovery-patterns.md) |

## Error Type Design

### Custom Error Classes

```typescript
// Base error with context
class AppError extends Error {
  constructor(
    message: string,
    public readonly code: string,
    public readonly context?: Record<string,