Frontend Development

This document outlines the development practices, guidelines, and improvement roadmap for the Four-Sided Triangle frontend application.

Development Environment

Prerequisites

• Node.js 18+
• Yarn package manager
• TypeScript 4.9+
• Next.js 13+

Setup

cd frontend
yarn install
yarn dev

Environment Configuration

# .env.local
NEXT_PUBLIC_API_URL=http://localhost:8000
NEXT_PUBLIC_WS_URL=ws://localhost:8000/ws

Development Guidelines

Code Quality Standards

• TypeScript: 95%+ coverage for all components
• ESLint: Enforced code quality rules
• Prettier: Consistent code formatting
• JSDoc: Comprehensive documentation for all functions

Component Development

• Follow React functional component patterns
• Use TypeScript for type safety
• Implement proper error boundaries
• Maintain clear component interfaces
• Document all props and state

Testing Strategy

• Unit Tests: Jest for component logic
• Integration Tests: React Testing Library
• End-to-End Tests: Cypress for critical workflows
• Performance Tests: Lighthouse CI

Improvement Roadmap

Phase 1: Foundation Improvements

Timeline: Weeks 1-6

Goals

• Modernize codebase with TypeScript migration
• Improve component structure and organization
• Enhance accessibility compliance
• Establish comprehensive testing practices

Key Tasks

• Complete TypeScript migration for all components
• Restructure component hierarchy
• Implement WCAG AA accessibility standards
• Set up comprehensive test suite
• Create component documentation

Phase 2: User Experience Enhancements

Timeline: Weeks 7-12

Goals

• Implement responsive design for all components
• Enhance query interface with advanced features
• Improve loading states and error handling
• Add user preference options

Key Tasks

• Responsive design implementation
• Advanced query interface features
• Enhanced loading states with skeleton loaders
• Dark mode theme implementation
• User preference management

Phase 3: Advanced Features

Timeline: Weeks 13-18

Goals

• Create visual selectors for domain expert models
• Implement comparison views for different model outputs
• Add visualization tools for complex data
• Enhance export and sharing capabilities

Key Tasks

• Domain expert model integration
• Multi-model comparison views
• Advanced data visualization tools
• Export functionality (JSON, CSV, PDF)
• Social sharing capabilities

Phase 4: Performance Optimization

Timeline: Weeks 19-24

Goals

• Implement code splitting and lazy loading
• Add caching mechanisms for frequent queries
• Optimize rendering performance
• Implement service workers for offline capabilities

Key Tasks

• Code splitting for major components
• Service worker implementation
• Request caching optimization
• Progressive Web App features
• Performance monitoring

Current Task Status

UI Components

• Responsive design for mobile compatibility
• Dark mode theme with user toggle
• Skeleton loaders instead of spinners
• Error boundary components
• Toast notification system

Query Interface

• Syntax highlighting for technical terms
• Autocomplete for domain terminology
• Query history tracking
• Save/favorite functionality
• Export functionality for results

Domain Expert Integration

• Visual selector for domain models
• Comparison view for model results
• Confidence score visualization
• Detailed metric tooltips
• Model feedback mechanism

Performance Optimization

• Code splitting implementation
• Service worker for offline capabilities
• Lazy loading for images (WebP format)
• Memoization for expensive calculations
• Request caching for frequent data

Accessibility

• ARIA attributes for interactive elements
• Keyboard navigation support
• Screen reader compatibility
• WCAG AA color contrast compliance
• Accessibility documentation

Component Architecture

Design Patterns

• Container/Presentational: Separate logic from presentation
• Custom Hooks: Reusable stateful logic
• Compound Components: Related component groupings
• Render Props: Flexible component composition

State Management

• React Context: Global state management
• useState/useReducer: Local component state
• SWR: Server state management and caching
• Zustand: Complex state management (when needed)

Performance Patterns

• React.memo: Prevent unnecessary re-renders
• useMemo: Expensive computation caching
• useCallback: Function reference stability
• Lazy Loading: Component and route splitting

Quality Assurance

Automated Testing

# Unit tests
yarn test

# Integration tests
yarn test:integration

# End-to-end tests
yarn test:e2e

# Performance tests
yarn test:performance

Code Quality Checks

# Linting
yarn lint

# Type checking
yarn type-check

# Format checking
yarn format:check

Performance Monitoring

• Core Web Vitals tracking
• Bundle size monitoring
• Render performance analysis
• API response time tracking

Deployment Strategy

Development Workflow

1. Feature branch development
2. Pull request review process
3. Automated testing and quality checks
4. Staging environment deployment
5. Production deployment with feature flags

Continuous Integration

• GitHub Actions for automated testing
• Quality gate enforcement
• Performance regression detection
• Security vulnerability scanning

Feature Management

• Feature flags for gradual rollouts
• A/B testing capabilities
• User feedback collection
• Performance impact monitoring

Success Metrics

Code Quality

• 95%+ TypeScript coverage
• 90%+ test coverage for critical paths
• Zero accessibility violations
• 20% improvement in Core Web Vitals

User Experience

• Positive user feedback scores
• Reduced bounce rates
• Increased feature adoption
• Improved task completion rates

Performance

• Bundle size optimization
• Faster page load times
• Reduced memory usage
• Improved mobile performance

Tools and Technologies

Core Stack

• Next.js 13+: React framework with app router
• TypeScript: Type-safe development
• Tailwind CSS: Utility-first styling
• React Query: Server state management

Development Tools

• ESLint: Code quality enforcement
• Prettier: Code formatting
• Husky: Git hooks
• Lint-staged: Pre-commit checks

Testing Framework

• Jest: Unit testing
• React Testing Library: Component testing
• Cypress: End-to-end testing
• Lighthouse CI: Performance testing

Build and Deployment

• Vercel: Hosting and deployment
• GitHub Actions: CI/CD pipeline
• SWR: Data fetching and caching
• Sentry: Error monitoring