leptos-shadcn-ui/docs/remediation/components/badge/DESIGN.md

🎯 Badge Component Design

Senior Rust Staff Engineer Review - September 20, 2025

📋 Component Overview

The Badge component displays small status indicators, notifications, or labels. It provides a compact way to show counts, status, or other contextual information with various styles and positions.

Current Status

• File Size: 60 lines (default.rs) - ✅ COMPLIANT
• Test Coverage: 3 test files - ✅ MODERATE
• Priority: P2 - Medium Priority

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🎨 Design Principles

1. Accessibility First

• ARIA Support: Full ARIA attributes for screen readers
• Color Contrast: Meets WCAG 2.1 AA standards
• Screen Reader Support: Proper announcements for badges
• Focus Management: Clear focus indicators

2. Performance Optimized

• Lightweight: Minimal bundle impact
• Memory Management: Proper cleanup of resources
• Signal Management: Efficient reactive state updates
• Bundle Size: Minimal impact on application bundle

3. Developer Experience

• Type Safety: Full TypeScript support with proper prop types
• Composable: Easy to extend and customize
• Consistent API: Follows established patterns
• Documentation: Comprehensive examples and guides

---

🏗️ Architecture

Core Components

// Main badge container
pub struct Badge {
    pub variant: BadgeVariant,
    pub size: BadgeSize,
    pub position: BadgePosition,
    pub count: Option<u32>,
    pub max_count: Option<u32>,
    pub show_zero: bool,
    pub class: Option<String>,
    pub children: Children,
}

// Badge content
pub struct BadgeContent {
    pub class: Option<String>,
    pub children: Children,
}

State Management

// Badge state
pub struct BadgeState {
    pub is_visible: RwSignal<bool>,
    pub count_display: RwSignal<String>,
    pub animation_state: RwSignal<AnimationState>,
}

// Animation state
pub enum AnimationState {
    Entering,
    Visible,
    Exiting,
    Hidden,
}

---

🎯 API Design

Badge Props

pub struct BadgeProps {
    // Core functionality
    pub variant: BadgeVariant,                   // Badge type
    pub size: BadgeSize,                         // Badge size
    pub position: BadgePosition,                // Badge position
    pub count: Option<u32>,                      // Count value
    pub max_count: Option<u32>,                  // Maximum count
    pub show_zero: bool,                         // Show zero count
    
    // Styling
    pub class: Option<String>,                   // Custom CSS classes
    
    // Accessibility
    pub aria_label: Option<String>,              // ARIA label
    
    // Children
    pub children: Children,                      // Badge content
}

BadgeContent Props

pub struct BadgeContentProps {
    // Styling
    pub class: Option<String>,                   // Custom CSS classes
    
    // Children
    pub children: Children,                      // Content
}

---

🎨 Visual Design

Variants

pub enum BadgeVariant {
    Default,    // Standard badge
    Destructive, // Error/danger badge
    Warning,    // Warning badge
    Success,    // Success badge
    Info,       // Information badge
    Secondary,  // Secondary badge
    Outline,    // Outline badge
}

Sizes

pub enum BadgeSize {
    Small,      // 16px
    Medium,     // 20px
    Large,      // 24px
}

Positions

pub enum BadgePosition {
    TopRight,   // Top right corner
    TopLeft,    // Top left corner
    BottomRight, // Bottom right corner
    BottomLeft, // Bottom left corner
    Center,     // Center position
}

States

• Visible: Badge is shown
• Hidden: Badge is hidden
• Animating: Transition state
• Focused: Keyboard focus state

---

🧪 Testing Strategy

Unit Tests

• Basic Rendering: Component renders without errors
• Props Handling: All props are properly applied
• Variant Styling: Different variants render correctly
• Size Styling: Different sizes render correctly
• Position Styling: Different positions render correctly

Integration Tests

• Multiple Badges: Multiple badges work together
• Count Display: Count values display correctly
• Max Count: Max count functionality works
• Show Zero: Show zero behavior works
• Animation States: Transitions work correctly

Accessibility Tests

• Screen Reader: Content is announced correctly
• Color Contrast: Meets WCAG 2.1 AA standards
• ARIA Attributes: Proper ARIA implementation
• Focus Indicators: Focus is clearly visible

Performance Tests

• Rendering Performance: Fast initial render
• Memory Usage: No memory leaks
• Bundle Size: Minimal impact on bundle
• Signal Updates: Efficient reactive updates

---

🚀 Implementation Plan

Phase 1: Core Implementation (Week 1)

• Basic Structure: Create core component files
• Props Definition: Define all prop types
• State Management: Implement reactive state
• Basic Rendering: Simple badge functionality

Phase 2: Advanced Features (Week 2)

• Variants: Implement all badge variants
• Sizes: Implement all badge sizes
• Positions: Implement all badge positions
• Count Logic: Count display and max count

Phase 3: Testing & Documentation (Week 3)

• Unit Tests: Comprehensive test coverage
• Integration Tests: Multi-badge scenarios
• Accessibility Tests: Screen reader and keyboard
• Documentation: Examples and guides

Phase 4: Optimization (Week 4)

• Performance: Optimize rendering and memory
• Bundle Size: Minimize impact on bundle
• Signal Management: Efficient reactive updates
• Final Testing: End-to-end validation

---

📊 Success Metrics

Functionality

• Basic Badge: Badge displays correctly
• Variants: All variants render properly
• Sizes: All sizes render properly
• Positions: All positions render properly

Accessibility

• Screen Reader: Content is announced correctly
• Color Contrast: Meets WCAG 2.1 AA standards
• ARIA Compliance: Meets WCAG 2.1 AA standards
• Focus Management: Focus moves correctly

Performance

• Rendering: Fast initial render (< 16ms)
• Memory: No memory leaks
• Bundle Size: Minimal impact (< 2KB)
• Updates: Efficient reactive updates

Developer Experience

• Type Safety: Full TypeScript support
• Documentation: Comprehensive examples
• API Consistency: Follows established patterns
• Error Handling: Clear error messages

---

🎯 Conclusion

The Badge component is a medium priority component that requires moderate test coverage improvements. The component follows accessibility-first design principles with comprehensive screen reader support and proper color contrast.

Key Focus Areas:

1. Test Coverage: Expand from 3 to 5+ test files
2. File Size: Ensure all files under 300 lines
3. Accessibility: Comprehensive ARIA support
4. Performance: Optimize rendering and memory usage

Expected Outcome: A production-ready, fully-accessible, well-tested badge component that meets enterprise standards.

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Badge Component Design created: September 20, 2025
Next review: October 20, 2025