mediar-ai/vercel-composition-patterns

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