Component Composition

Component Composition

Agent Workflow (MANDATORY)

Before implementation, use TeamCreate to spawn 3 agents:

1. fuse-ai-pilot:explore-codebase - Check existing composition patterns
2. fuse-ai-pilot:research-expert - React 19 composition patterns

After: Run fuse-ai-pilot:sniper for validation.

Overview

Quick Reference

Children Pattern

function Card({ children }: { children: React.ReactNode }) {
  return <div className="bg-surface rounded-2xl p-6">{children}</div>;
}

Slots Pattern

function Card({ header, footer, children }: CardProps) {
  return (
    <div className="bg-surface rounded-2xl">
      {header && <div className="px-6 py-4 border-b">{header}</div>}
      <div className="p-6">{children}</div>
      {footer && <div className="px-6 py-4 border-t">{footer}</div>}
    </div>
  );
}

Compound Components

function Card({ children, variant }) {
  return (
    <CardContext.Provider value={{ variant }}>
      <div className="bg-surface rounded-2xl">{children}</div>
    </CardContext.Provider>
  );
}

Card.Header = ({ children }) => <div className="px-6 py-4">{children}</div>;
Card.Body = ({ children }) => <div className="p-6">{children}</div>;
Card.Footer = ({ children }) => <div className="px-6 py-4">{children}</div>;

// Usage
<Card>
  <Card.Header>Title</Card.Header>
  <Card.Body>Content</Card.Body>
</Card>

Polymorphic Components

function Button<T extends React.ElementType = "button">({
  as,
  children,
  ...props
}: ButtonProps<T>) {
  const Component = as || "button";
  return <Component className="btn" {...props}>{children}</Component>;
}

// Usage
<Button as="a" href="/link">Link</Button>

Validation Checklist

[ ] Appropriate pattern for complexity
[ ] TypeScript props properly typed
[ ] displayName set on forwardRef
[ ] Max 2-3 composition levels

Best Practices

DO

• Use children for simple nesting
• Use slots for named regions (max 3-4)
• Forward refs for form elements
• Set displayName

DON'T

• Over-engineer simple components
• Create deep nesting (max 2 levels)
• Forget TypeScript types
• Skip ref forwarding