Vercel Composition Patterns

---
name: vercel-composition-patterns
description: >-
  Refactors React components with composition patterns: compound components, context providers and
  slots instead of boolean-prop explosions, flexible component library APIs, and React 19 API
  changes. Use when a component has too many boolean props or variants, the user asks to refactor
  a Modal, Card or Form API, or mentions compound components or render props. Not for performance
  (use vercel-react-best-practices).
license: MIT
metadata:
  author: vercel
  version: '1.0.0'
---

# React Composition Patterns

Composition patterns for building flexible, maintainable React components. Avoid
boolean prop proliferation by using compound components, lifting state, and
composing internals. These patterns make codebases easier for both humans and AI
agents to work with as they scale.

## When to Apply

Reference these guidelines when:

- Refactoring components with many boolean props
- Building reusable component libraries
- Designing flexible component APIs
- Reviewing component architecture
- Working with compound components or context providers

## Rule Categories by Priority

| Priority | Category                | Impact | Prefix          |
| -------- | ----------------------- | ------ | --------------- |
| 1        | Component Architecture  | HIGH   | `architecture-` |
| 2        | State Management        | MEDIUM | `state-`        |
| 3        | Implementation Patterns | MEDIUM | `patterns-`     |
| 4        | React 19 APIs           | MEDIUM | `react19-`      |

## Quick Reference

### 1. Component Architecture (HIGH)

- `architecture-avoid-boolean-props` - Don't add boolean props to customize
  behavior; use composition
- `architecture-compound-components` - Structure complex components with shared
  context

### 2. State Management (MEDIUM)

- `state-decouple-implementation` - Provider is the only place that knows how
  state is managed
- `state-context-interface` - Define generic interface with state, actions, meta
  for dependency injection
- `state-lift-state` - Move state into provider components for sibling access

### 3. Implementation Patterns (MEDIUM)

- `patterns-explicit-variants` - Create explicit variant components instead of
  boolean modes
- `patterns-children-over-render-props` - Use children for composition instead
  of renderX props

### 4. React 19 APIs (MEDIUM)

> **⚠️ React 19+ only.** Skip this section if using React 18 or earlier.

- `react19-no-forwardref` - Don't use `forwardRef`; use `use()` instead of `useContext()`

## How to Use

Read individual rule files for detailed explanations and code examples:

```
rules/architecture-avoid-boolean-props.md
rules/state-context-interface.md
```

Each rule file contains:

- Brief explanation of why it matters
- Incorrect code example with explanation
- Correct code example with explanation
- Additional context and references

## Full Compiled Document

For the complete guide with all rules expanded: `AGENTS.md`