React Hooks

React Hooks Skill

Handles common React hook patterns and violations across the codebase.

Capabilities

• Rules of Hooks violations: Early returns before hook calls, conditional hooks
• useEffect dependency issues: Missing/stale dependencies, infinite loops
• Hook ordering problems: Hooks called in conditional order, inconsistent hook sequence
• Context hook patterns: Proper use of useContext, avoiding unnecessary context re-renders
• Custom hook extraction: Safe creation of custom hooks for reusable logic

Key Patterns

Pattern 1: Early Returns Before Hooks (⚠️ FATAL)

// WRONG - return before hooks
if (!isAuthenticated) {
  return <Login />;  // ❌ Hook call below is unreachable sometimes
}
const user = useUser();  // VIOLATION

// RIGHT - hooks always execute
const user = useUser();
if (!isAuthenticated) {
  return <Login />;
}

Pattern 2: useEffect Dependency Problems

// WRONG - missing dependency
const context = useContext(MyContext);
useEffect(() => {
  doSomething(context);
}, []);  // ❌ Missing `context`

// RIGHT - include all dependencies
useEffect(() => {
  doSomething(context);
}, [context]);

Pattern 3: Infinite Loop from Context Object

// WRONG - context object changes on every render
const Provider = ({ children }) => {
  const value = { user: currentUser };  // New object every render
  return (
    <MyContext.Provider value={value}>  // ❌ Causes infinite loop
      {children}
    </MyContext.Provider>
  );
};

// RIGHT - memoize context value
const Provider = ({ children }) => {
  const value = useMemo(() => ({ user: currentUser }), [currentUser]);
  return (
    <MyContext.Provider value={value}>
      {children}
    </MyContext.Provider>
  );
};

Debugging Workflow

1. Identify the error: Check browser console for hook violations.
2. Find the violation: search for early returns or dependency issues.
3. Locate the component: Grep for hook name or variable.
4. Apply fix: Use the patterns above as templates.
5. Test: Re-render and check console.

Instrumentation

./scripts/log-skill.sh react-hooks