durable-objects-pattern-checker

# Durable Objects Pattern Checker SKILL

## Activation Patterns

This SKILL automatically activates when:
- Durable Object imports or exports are detected
- DO stub creation and usage patterns
- State management in Durable Objects
- ID generation patterns (`idFromName`, `newUniqueId`)
- Hibernation and lifecycle patterns
- WebSocket or real-time features with DOs

## Expertise Provided

### Durable Objects Best Practices
- **State Management**: Ensures proper state persistence and consistency
- **ID Generation**: Validates correct ID patterns for different use cases
- **Hibernation**: Checks for proper hibernation implementation
- **Lifecycle Management**: Validates constructor, fetch, and alarm handling
- **Strong Consistency**: Ensures DOs are used when strong consistency is needed
- **Performance**: Identifies DO performance anti-patterns

### Specific Checks Performed

#### ❌ Durable Objects Anti-Patterns
```typescript
// These patterns trigger immediate alerts:
// Using DOs for stateless operations
export default {
  async fetch(request: Request, env: Env) {
    const id = env.COUNTER.newUniqueId();  // New DO every request!
    const stub = env.COUNTER.get(id);
    return stub.fetch(request);  // Overkill for simple counter
  }
}

// Missing hibernation for long-lived DOs
export class ChatRoom {
  constructor(state, env) {
    this.state = state;
    // Missing this.state.storage.setAlarm() for hibernation
  }
}
```

#### ✅ Durable Objects Best Practices
```typescript
// These patterns are validated as correct:
// Reuse DO instances for stateful coordination
export default {
  async fetch(request: Request, env: Env) {
    const ip = request.headers.get('CF-Connecting-IP');
    const id = env.RATE_LIMITER.idFromName(ip);  // Reuse same DO
    const stub = env.RATE_LIMITER.get(id);
    return stub.fetch(request);
  }
}

// Proper hibernation implementation
export class ChatRoom {
  constructor(state, env) {
    this.state = state;
    this.env = env;
    
    //