Review: State Management

Checklist

State Immutability

• No direct state mutation
• Using spread operators or immutable update patterns
• Arrays updated with map/filter/concat (not push/splice)
• Objects updated with spread or Object.assign

State Location

• Local state used when appropriate
• Context only for cross-cutting concerns
• No prop drilling through 3+ levels
• Frequently changing state not in Context

useReducer Usage

• Used for complex state logic
• Reducer functions are pure
• Action types are consistent
• State updates follow patterns

Context Patterns

• Split contexts for different concerns
• Using use() API in React 19 (not useContext)
• Context providers at appropriate level
• No unnecessary re-renders

Anti-Patterns

• ❌ Direct state mutation (state.push(), state.x = y)
• ❌ Context for frequently changing values
• ❌ Excessive prop drilling
• ❌ God components managing too much state

For comprehensive state patterns, see: research/react-19-comprehensive.md.