# Error Handling Standards ## Current State: INCONSISTENT Error handling varies across the codebase - some functions have comprehensive error handling while others are missing it entirely. ## Required Error Handling Patterns ### 1. Error Boundaries (MISSING) Implement React error boundaries for component-level error handling: ```typescript // ✅ IMPLEMENT - ThemeErrorBoundary.tsx import React, { Component, ErrorInfo, ReactNode } from 'react'; interface Props { children: ReactNode; fallback?: ReactNode; } interface State { hasError: boolean; error?: Error; } export class ThemeErrorBoundary extends Component { constructor(props: Props) { super(props); this.state = { hasError: false }; } static getDerivedStateFromError(error: Error): State { return { hasError: true, error }; } componentDidCatch(error: Error, errorInfo: ErrorInfo) { console.error('Theme component error:', error, errorInfo); // Log to error reporting service in production } render() { if (this.state.hasError) { return this.props.fallback || (

Something went wrong

There was an error loading the theme system.

); } return this.props.children; } } ``` ### 2. Async Error Handling (STANDARDIZE) Consistent pattern for all async operations: ```typescript // ✅ STANDARD PATTERN const performAsyncOperation = async (id: string) => { try { setLoading(true); setError(null); const result = await riskyOperation(id); if (!result) { throw new Error(`Operation failed for ${id}`); } return result; } catch (error) { const message = error instanceof Error ? error.message : 'Unknown error occurred'; setError(message); console.error(`Async operation failed:`, error); throw error; // Re-throw if caller needs to handle } finally { setLoading(false); } }; ``` ### 3. Hook Error Handling (IMPLEMENT) Custom hook for consistent error states: ```typescript // ✅ IMPLEMENT - useAsyncOperation.ts import { useState, useCallback } from 'react'; interface AsyncState { data: T | null; loading: boolean; error: string | null; } export function useAsyncOperation() { const [state, setState] = useState>({ data: null, loading: false, error: null }); const execute = useCallback(async (operation: () => Promise) => { setState(prev => ({ ...prev, loading: true, error: null })); try { const data = await operation(); setState({ data, loading: false, error: null }); return data; } catch (error) { const message = error instanceof Error ? error.message : 'Operation failed'; setState(prev => ({ ...prev, loading: false, error: message })); throw error; } }, []); return { ...state, execute }; } ``` ### 4. Network Error Handling (ENHANCE) Standardized fetch error handling: ```typescript // ✅ STANDARD PATTERN const fetchWithErrorHandling = async (url: string, options?: RequestInit) => { try { const response = await fetch(url, options); if (!response.ok) { throw new Error(`HTTP ${response.status}: ${response.statusText}`); } return response; } catch (error) { if (error instanceof TypeError) { throw new Error('Network error - check your connection'); } throw error; } }; ``` ## Error Types & Classifications ### 1. User Errors (Recoverable) - Invalid theme selection - Missing form data - File upload issues **Handling**: Show user-friendly message, allow retry ### 2. System Errors (Technical) - Network failures - Parse errors - Configuration issues **Handling**: Log details, show generic message, provide fallback ### 3. Critical Errors (Unrecoverable) - Dependency failures - Memory issues - Corrupt data **Handling**: Error boundary, full page reload option ## Logging Standards ### Development ```typescript // ✅ PATTERN console.group(`🔥 ${operation} Error`); console.error('Details:', error); console.error('Context:', context); console.groupEnd(); ``` ### Production ```typescript // ✅ PATTERN (when error service added) errorReportingService.captureException(error, { context, user: getCurrentUser(), timestamp: new Date().toISOString() }); ``` ## Error Message Standards ### User-Facing Messages - **Clear & Actionable**: "Could not load theme. Please try again." - **No technical jargon**: Avoid error codes, stack traces - **Suggest solutions**: "Check your connection and retry" ### Developer Messages - **Detailed context**: Include operation, parameters, state - **Stack traces**: Preserve for debugging - **Structured data**: Consistent error object format ## Implementation Checklist ### HIGH PRIORITY - [ ] Add ThemeErrorBoundary to App.tsx - [ ] Implement useAsyncOperation hook - [ ] Standardize theme loading error handling - [ ] Add network error handling to fetch operations ### MEDIUM PRIORITY - [ ] Create error fallback components - [ ] Add error recovery mechanisms (retry buttons) - [ ] Implement error state consistency across components - [ ] Add loading state management standards ### LOW PRIORITY - [ ] Add error reporting service integration - [ ] Implement error analytics tracking - [ ] Add error rate monitoring - [ ] Create error handling documentation ## Testing Requirements - **Error boundary testing**: Verify fallback rendering - **Async error testing**: Test network failures, timeouts - **Recovery testing**: Ensure retry mechanisms work - **Error state testing**: Verify error messages display correctly ## Current Problem Areas ### Missing Error Boundaries No React error boundaries implemented - component errors crash the app ### Inconsistent Async Patterns Some async operations handle errors, others don't: - `themeLoader.ts` ✅ Has good error handling - Some components ❌ Missing error handling ### No Error Recovery Users cannot recover from errors - no retry buttons or reload options ### Logging Inconsistency Mix of `console.warn`, `console.error`, and no logging