low-code-react-app-b/docs/composite-components-quick-reference.md

Composite Components - Quick Reference

What are Composite Components?

Composite components are pre-assembled, reusable UI sections that combine multiple smaller components (atoms and molecules) into cohesive, functional units (organisms).

Schema Editor Composites

Core Panels

SchemaEditorToolbar

Purpose: Top action bar with import/export controls Location: src/components/organisms/SchemaEditorToolbar.tsx

<SchemaEditorToolbar
  onImport={() => {}}
  onExport={() => {}}
  onCopy={() => {}}
  onPreview={() => {}}
  onClear={() => {}}
/>

SchemaEditorSidebar

Purpose: Left panel with component palette Location: src/components/organisms/SchemaEditorSidebar.tsx

<SchemaEditorSidebar
  onDragStart={(component, e) => {}}
/>

SchemaEditorCanvas

Purpose: Central canvas for rendering components Location: src/components/organisms/SchemaEditorCanvas.tsx

<SchemaEditorCanvas
  components={components}
  selectedId={selectedId}
  hoveredId={hoveredId}
  draggedOverId={draggedOverId}
  dropPosition={dropPosition}
  onSelect={setSelectedId}
  onHover={setHoveredId}
  onHoverEnd={() => setHoveredId(null)}
  onDragOver={handleDragOver}
  onDragLeave={handleDragLeave}
  onDrop={handleDrop}
/>

SchemaEditorPropertiesPanel

Purpose: Right panel with component tree and property editor Location: src/components/organisms/SchemaEditorPropertiesPanel.tsx

<SchemaEditorPropertiesPanel
  components={components}
  selectedId={selectedId}
  hoveredId={hoveredId}
  draggedOverId={draggedOverId}
  dropPosition={dropPosition}
  selectedComponent={selectedComponent}
  onSelect={setSelectedId}
  onHover={setHoveredId}
  onHoverEnd={() => setHoveredId(null)}
  onDragStart={handleTreeDragStart}
  onDragOver={handleDragOver}
  onDragLeave={handleDragLeave}
  onDrop={handleDrop}
  onUpdate={handleUpdate}
  onDelete={handleDelete}
/>

Supporting Composites

EmptyCanvasState

Purpose: Empty state when no components exist Location: src/components/organisms/EmptyCanvasState.tsx

<EmptyCanvasState
  onAddFirstComponent={() => {}}
  onImportSchema={() => {}}
/>

SchemaEditorStatusBar

Purpose: Bottom status bar showing metrics Location: src/components/organisms/SchemaEditorStatusBar.tsx

<SchemaEditorStatusBar
  componentCount={components.length}
  selectedComponentType={selectedComponent?.type}
  hasUnsavedChanges={false}
/>

SchemaCodeViewer

Purpose: View generated JSON schema Location: src/components/organisms/SchemaCodeViewer.tsx

<SchemaCodeViewer
  components={components}
  schema={schema}
/>

Complete Layout

SchemaEditorLayout

Purpose: Orchestrates all panels into complete editor Location: src/components/organisms/SchemaEditorLayout.tsx

<SchemaEditorLayout
  components={components}
  selectedId={selectedId}
  hoveredId={hoveredId}
  draggedOverId={draggedOverId}
  dropPosition={dropPosition}
  selectedComponent={selectedComponent}
  onSelect={setSelectedId}
  onHover={setHoveredId}
  onHoverEnd={() => setHoveredId(null)}
  onComponentDragStart={handleComponentDragStart}
  onTreeDragStart={handleTreeDragStart}
  onDragOver={handleDragOver}
  onDragLeave={handleDragLeave}
  onDrop={handleDrop}
  onUpdate={handleUpdate}
  onDelete={handleDelete}
  onImport={handleImport}
  onExport={handleExport}
  onCopy={handleCopy}
  onPreview={handlePreview}
  onClear={clearAll}
/>

When to Use

Use Composite Components When:

✅ Building complete features (full page editors, dashboards) ✅ Need to enforce consistent layouts ✅ Want to abstract complexity from page components ✅ Creating reusable feature modules

Use Individual Components When:

✅ Building custom layouts ✅ Need fine-grained control ✅ Creating new composite components ✅ Testing specific functionality

Benefits

1. Reduced Duplication: Reuse complex layouts across pages
2. Consistency: Same look and behavior everywhere
3. Maintainability: Change once, update everywhere
4. Testability: Test complete features in isolation
5. Documentation: Self-documenting through composition

Creating New Composites

Step 1: Identify the Pattern

Look for repeated component combinations in your code.

Step 2: Create the Organism

// src/components/organisms/MyComposite.tsx
interface MyCompositeProps {
  // data props
  items: Item[]
  selectedId: string | null
  
  // action props
  onSelect: (id: string) => void
  onUpdate: (item: Item) => void
}

export function MyComposite({ 
  items, 
  selectedId, 
  onSelect, 
  onUpdate 
}: MyCompositeProps) {
  return (
    <div className="flex flex-col">
      <MyHeader />
      <MySidebar items={items} onSelect={onSelect} />
      <MyContent 
        item={items.find(i => i.id === selectedId)}
        onUpdate={onUpdate}
      />
    </div>
  )
}

Step 3: Export from Index

// src/components/organisms/index.ts
export { MyComposite } from './MyComposite'

Step 4: Document

Add usage examples and prop descriptions.

Common Patterns

Panel Wrapper Pattern

function MyPanel({ children }: { children: React.ReactNode }) {
  return (
    <div className="border-r border-border bg-card">
      <div className="p-4 border-b">
        <h2>Panel Title</h2>
      </div>
      <div className="p-4">
        {children}
      </div>
    </div>
  )
}

Action Bar Pattern

function MyActionBar({ onAction1, onAction2 }: ActionBarProps) {
  return (
    <div className="flex items-center gap-2 p-2 border-b">
      <Button onClick={onAction1}>Action 1</Button>
      <Button onClick={onAction2}>Action 2</Button>
    </div>
  )
}

Split View Pattern

function MySplitView({ left, right }: SplitViewProps) {
  return (
    <div className="flex h-full">
      <div className="w-1/2 border-r">{left}</div>
      <div className="w-1/2">{right}</div>
    </div>
  )
}

Best Practices

1. Keep Props Focused: Each composite should have a clear, single purpose
2. Expose Necessary Callbacks: Don't hide important events
3. Support Composition: Allow children or render props when needed
4. Document Extensively: Provide examples and use cases
5. Test Thoroughly: Test with various prop combinations
6. Keep LOC < 150: Break down if it gets too large

Related Docs

• Atomic Design Principles
• Schema Editor Architecture
• Component Guidelines