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

🎯 Accordion Component Design

Senior Rust Staff Engineer Review - September 20, 2025

📋 Component Overview

The Accordion component provides a vertically stacked set of collapsible content sections. Each section can be expanded or collapsed independently, allowing users to focus on specific content while keeping the interface clean and organized.

Current Status

• File Size: 287 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
• Keyboard Navigation: Arrow keys, Enter, Space, Tab navigation
• Focus Management: Clear focus indicators and logical tab order
• Screen Reader Support: Proper announcements for state changes

2. Performance Optimized

• Lazy Loading: Content loaded only when expanded
• Memory Management: Proper cleanup of event listeners
• 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 accordion container
pub struct Accordion {
    pub value: Option<String>,
    pub on_value_change: Option<Callback<String>>,
    pub collapsible: bool,
    pub class: Option<String>,
    pub children: Children,
}

// Individual accordion item
pub struct AccordionItem {
    pub value: String,
    pub disabled: bool,
    pub class: Option<String>,
    pub children: Children,
}

// Accordion trigger (header)
pub struct AccordionTrigger {
    pub class: Option<String>,
    pub children: Children,
}

// Accordion content (body)
pub struct AccordionContent {
    pub class: Option<String>,
    pub children: Children,
}

State Management

// Accordion state
pub struct AccordionState {
    pub open_items: RwSignal<HashSet<String>>,
    pub focused_item: RwSignal<Option<String>>,
    pub keyboard_navigation: RwSignal<bool>,
}

// Accordion item state
pub struct AccordionItemState {
    pub is_open: RwSignal<bool>,
    pub is_focused: RwSignal<bool>,
    pub is_disabled: RwSignal<bool>,
}

---

🎯 API Design

Accordion Props

pub struct AccordionProps {
    // Core functionality
    pub value: Option<String>,                    // Currently open item
    pub on_value_change: Option<Callback<String>>, // Value change callback
    pub collapsible: bool,                        // Allow all items to be closed
    
    // Styling
    pub class: Option<String>,                    // Custom CSS classes
    pub variant: AccordionVariant,               // Visual variant
    
    // Accessibility
    pub aria_label: Option<String>,              // ARIA label
    pub aria_labelledby: Option<String>,         // ARIA labelledby
    
    // Children
    pub children: Children,                      // Accordion items
}

AccordionItem Props

pub struct AccordionItemProps {
    // Core functionality
    pub value: String,                           // Unique identifier
    pub disabled: bool,                          // Disabled state
    
    // Styling
    pub class: Option<String>,                   // Custom CSS classes
    
    // Children
    pub children: Children,                     // Trigger and content
}

AccordionTrigger Props

pub struct AccordionTriggerProps {
    // Styling
    pub class: Option<String>,                   // Custom CSS classes
    
    // Children
    pub children: Children,                     // Trigger content
}

AccordionContent Props

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

---

🎨 Visual Design

Variants

pub enum AccordionVariant {
    Default,    // Standard accordion
    Bordered,   // With borders between items
    Filled,     // Filled background
    Ghost,      // Transparent background
}

Sizes

pub enum AccordionSize {
    Small,      // Compact spacing
    Medium,     // Standard spacing
    Large,      // Generous spacing
}

States

• Closed: Collapsed state with trigger visible
• Open: Expanded state with content visible
• Disabled: Non-interactive state
• Focused: Keyboard focus state
• Hover: Mouse hover state

---

🧪 Testing Strategy

Unit Tests

• Basic Rendering: Component renders without errors
• Props Handling: All props are properly applied
• State Management: Open/close state works correctly
• Event Handling: Click and keyboard events work
• Accessibility: ARIA attributes are correct

Integration Tests

• Multiple Items: Multiple accordion items work together
• Collapsible Behavior: Collapsible prop works correctly
• Value Changes: on_value_change callback fires
• Keyboard Navigation: Arrow keys, Enter, Space work
• Focus Management: Focus moves correctly

Accessibility Tests

• Screen Reader: Content is announced correctly
• Keyboard Navigation: All interactions work with keyboard
• Focus Indicators: Focus is clearly visible
• ARIA Attributes: Proper ARIA implementation

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 accordion functionality

Phase 2: Advanced Features (Week 2)

• Keyboard Navigation: Arrow keys, Enter, Space
• Accessibility: ARIA attributes and screen reader support
• Styling: Variants and size options
• Event Handling: Click and keyboard events

Phase 3: Testing & Documentation (Week 3)

• Unit Tests: Comprehensive test coverage
• Integration Tests: Multi-item 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 Accordion: Open/close functionality works
• Multiple Items: Multiple items work together
• Collapsible: All items can be closed
• Value Changes: Callbacks fire correctly

Accessibility

• Screen Reader: Content is announced correctly
• Keyboard Navigation: All interactions work with keyboard
• Focus Management: Focus moves correctly
• ARIA Compliance: Meets WCAG 2.1 AA standards

Performance

• Rendering: Fast initial render (< 16ms)
• Memory: No memory leaks
• Bundle Size: Minimal impact (< 5KB)
• 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 Accordion component is a medium priority component that requires moderate test coverage improvements and file size optimization. The component follows accessibility-first design principles with comprehensive keyboard navigation and screen reader support.

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 accordion component that meets enterprise standards.

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