dees-catalog/ts_web/elements/wysiwyg/phase4-summary.md

Phase 4 Implementation Summary - Heading Blocks Migration

Overview

Successfully migrated all heading blocks (h1, h2, h3) to the new block handler architecture using a unified HeadingBlockHandler class.

Changes Made

1. Created Unified Heading Handler

• File: blocks/text/heading.block.ts
• Implemented HeadingBlockHandler class extending BaseBlockHandler
• Single handler class that accepts heading level (1, 2, or 3) in constructor
• Extracted all heading rendering logic from dees-wysiwyg-block.ts
• Extracted heading setup logic with full text editing support:
  • Input handling with cursor tracking
  • Selection handling with Shadow DOM support
  • Focus/blur management
  • Composition events for IME support
  • Split content functionality
• Extracted all heading-specific styles for all three levels

2. Registration Updates

• File: wysiwyg.blockregistration.ts
• Registered three heading handlers using the same class:
  • heading-1 → new HeadingBlockHandler('heading-1')
  • heading-2 → new HeadingBlockHandler('heading-2')
  • heading-3 → new HeadingBlockHandler('heading-3')
• Updated imports to include HeadingBlockHandler

3. Updated Exports

• File: blocks/index.ts
• Exported HeadingBlockHandler class
• Removed TODO comment for heading handler

4. Handler Implementation Details

• Dynamic Level Handling: The handler determines the heading level from the block type
• Shared Styles: All heading levels share the same style method but render different CSS
• Placeholder Support: Each level has its own placeholder text
• Full Text Editing: Inherits all paragraph-like functionality:
  • Cursor position tracking
  • Text selection with Shadow DOM awareness
  • Content splitting for Enter key handling
  • Focus management with cursor positioning

Key Features Preserved

✅ All three heading levels render with correct styles ✅ Font sizes: h1 (32px), h2 (24px), h3 (20px) ✅ Proper font weights and line heights ✅ Theme-aware colors using cssManager.bdTheme ✅ Contenteditable functionality ✅ Selection and cursor tracking ✅ Keyboard navigation ✅ Focus/blur handling ✅ Placeholder text for empty headings

Architecture Benefits

1. Code Reuse: Single handler class for all heading levels
2. Consistency: All headings share the same behavior
3. Maintainability: Changes to heading behavior only need to be made once
4. Type Safety: Heading level is type-checked at construction
5. Scalability: Easy to add more heading levels if needed

Testing Results

• ✅ TypeScript compilation successful
• ✅ All three heading handlers registered correctly
• ✅ Render method produces correct HTML with proper classes
• ✅ Placeholders set correctly for each level
• ✅ All handlers are instances of HeadingBlockHandler

Next Steps

Continue with Phase 5 to migrate remaining text blocks:

• Quote block
• Code block
• List block

Each will follow the same pattern but with their specific requirements.