State Management Advisor

Choose and implement the right state management solution for React applications.

Quick Start

Use local state by default, Context for simple global state, Zustand for complex client state, and TanStack Query for server state.

Instructions

Decision Tree

Start here:

Is it server data (from API)? → Use TanStack Query
Is it used in one component only? → Use useState
Is it simple global state (theme, auth)? → Use Context
Is it complex client state? → Use Zustand or Redux Toolkit

Local State (useState)

For component-specific state.

Basic usage:

tsx

function Counter() {
  const [count, setCount] = useState(0);
  
  return (
    <button onClick={() => setCount(count + 1)}>
      Count: {count}
    </button>
  );
}

With objects:

tsx

function Form() {
  const [formData, setFormData] = useState({
    name: '',
    email: ''
  });
  
  const handleChange = (field: string, value: string) => {
    setFormData(prev => ({ ...prev, [field]: value }));
  };
  
  return (
    <form>
      <input
        value={formData.name}
        onChange={e => handleChange('name', e.target.value)}
      />
    </form>
  );
}

React Context

For simple global state shared across components.

Setup:

tsx

interface AuthContextValue {
  user: User | null;
  login: (credentials: Credentials) => Promise<void>;
  logout: () => void;
}

const AuthContext = createContext<AuthContextValue | null>(null);

export function AuthProvider({ children }: { children: React.ReactNode }) {
  const [user, setUser] = useState<User | null>(null);
  
  const login = async (credentials: Credentials) => {
    const user = await api.login(credentials);
    setUser(user);
  };
  
  const logout = () => {
    setUser(null);
  };
  
  return (
    <AuthContext.Provider value={{ user, login, logout }}>
      {children}
    </AuthContext.Provider>
  );
}

export function useAuth() {
  const context = useContext(AuthContext);
  if (!context) throw new Error('useAuth must be used within AuthProvider');
  return context;
}

Usage:

tsx

function App() {
  return (
    <AuthProvider>
      <Router />
    </AuthProvider>
  );
}

function Profile() {
  const { user, logout } = useAuth();
  return <div>{user?.name} <button onClick={logout}>Logout</button></div>;
}

Optimization - Split contexts:

tsx

// Separate frequently changing data
const ThemeContext = createContext<Theme>(null);
const ThemeUpdateContext = createContext<(theme: Theme) => void>(null);

function ThemeProvider({ children }) {
  const [theme, setTheme] = useState('light');
  
  return (
    <ThemeContext.Provider value={theme}>
      <ThemeUpdateContext.Provider value={setTheme}>
        {children}
      </ThemeUpdateContext.Provider>
    </ThemeContext.Provider>
  );
}

Zustand

Lightweight global state with minimal boilerplate.

Installation:

bash

npm install zustand

Basic store:

tsx

import { create } from 'zustand';

interface CounterStore {
  count: number;
  increment: () => void;
  decrement: () => void;
}

const useCounterStore = create<CounterStore>((set) => ({
  count: 0,
  increment: () => set((state) => ({ count: state.count + 1 })),
  decrement: () => set((state) => ({ count: state.count - 1 })),
}));

// Usage
function Counter() {
  const count = useCounterStore((state) => state.count);
  const increment = useCounterStore((state) => state.increment);
  
  return <button onClick={increment}>Count: {count}</button>;
}

With async actions:

tsx

interface UserStore {
  users: User[];
  loading: boolean;
  fetchUsers: () => Promise<void>;
}

const useUserStore = create<UserStore>((set) => ({
  users: [],
  loading: false,
  fetchUsers: async () => {
    set({ loading: true });
    const users = await api.fetchUsers();
    set({ users, loading: false });
  },
}));

With middleware:

tsx

import { persist } from 'zustand/middleware';

const useStore = create(
  persist(
    (set) => ({
      token: null,
      setToken: (token) => set({ token }),
    }),
    {
      name: 'auth-storage',
    }
  )
);

Redux Toolkit

For complex state with many interactions.

Installation:

bash

npm install @reduxjs/toolkit react-redux

Setup store:

tsx

import { configureStore, createSlice } from '@reduxjs/toolkit';

const counterSlice = createSlice({
  name: 'counter',
  initialState: { value: 0 },
  reducers: {
    increment: (state) => {
      state.value += 1;
    },
    decrement: (state) => {
      state.value -= 1;
    },
  },
});

export const { increment, decrement } = counterSlice.actions;

export const store = configureStore({
  reducer: {
    counter: counterSlice.reducer,
  },
});

export type RootState = ReturnType<typeof store.getState>;
export type AppDispatch = typeof store.dispatch;

Provider:

tsx

import { Provider } from 'react-redux';

function App() {
  return (
    <Provider store={store}>
      <Router />
    </Provider>
  );
}

Usage:

tsx

import { useSelector, useDispatch } from 'react-redux';

function Counter() {
  const count = useSelector((state: RootState) => state.counter.value);
  const dispatch = useDispatch();
  
  return (
    <button onClick={() => dispatch(increment())}>
      Count: {count}
    </button>
  );
}

Async with createAsyncThunk:

tsx

import { createAsyncThunk } from '@reduxjs/toolkit';

export const fetchUsers = createAsyncThunk(
  'users/fetch',
  async () => {
    const response = await api.fetchUsers();
    return response.data;
  }
);

const usersSlice = createSlice({
  name: 'users',
  initialState: { data: [], loading: false },
  reducers: {},
  extraReducers: (builder) => {
    builder
      .addCase(fetchUsers.pending, (state) => {
        state.loading = true;
      })
      .addCase(fetchUsers.fulfilled, (state, action) => {
        state.data = action.payload;
        state.loading = false;
      });
  },
});

TanStack Query (React Query)

For server state management.

Installation:

bash

npm install @tanstack/react-query

Setup:

tsx

import { QueryClient, QueryClientProvider } from '@tanstack/react-query';

const queryClient = new QueryClient();

function App() {
  return (
    <QueryClientProvider client={queryClient}>
      <Router />
    </QueryClientProvider>
  );
}

Fetching data:

tsx

import { useQuery } from '@tanstack/react-query';

function Users() {
  const { data, isLoading, error } = useQuery({
    queryKey: ['users'],
    queryFn: fetchUsers,
  });
  
  if (isLoading) return <Spinner />;
  if (error) return <Error message={error.message} />;
  
  return <UserList users={data} />;
}

Mutations:

tsx

import { useMutation, useQueryClient } from '@tanstack/react-query';

function CreateUser() {
  const queryClient = useQueryClient();
  
  const mutation = useMutation({
    mutationFn: createUser,
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['users'] });
    },
  });
  
  return (
    <button onClick={() => mutation.mutate({ name: 'John' })}>
      Create User
    </button>
  );
}

With parameters:

tsx

function User({ id }: { id: string }) {
  const { data } = useQuery({
    queryKey: ['user', id],
    queryFn: () => fetchUser(id),
  });
  
  return <div>{data?.name}</div>;
}

Optimistic updates:

tsx

const mutation = useMutation({
  mutationFn: updateUser,
  onMutate: async (newUser) => {
    await queryClient.cancelQueries({ queryKey: ['users'] });
    const previousUsers = queryClient.getQueryData(['users']);
    
    queryClient.setQueryData(['users'], (old) => [...old, newUser]);
    
    return { previousUsers };
  },
  onError: (err, newUser, context) => {
    queryClient.setQueryData(['users'], context.previousUsers);
  },
  onSettled: () => {
    queryClient.invalidateQueries({ queryKey: ['users'] });
  },
});

Jotai

Atomic state management.

Installation:

bash

npm install jotai

Basic atoms:

tsx

import { atom, useAtom } from 'jotai';

const countAtom = atom(0);

function Counter() {
  const [count, setCount] = useAtom(countAtom);
  
  return (
    <button onClick={() => setCount(count + 1)}>
      Count: {count}
    </button>
  );
}

Derived atoms:

tsx

const countAtom = atom(0);
const doubleCountAtom = atom((get) => get(countAtom) * 2);

function Display() {
  const [doubleCount] = useAtom(doubleCountAtom);
  return <div>Double: {doubleCount}</div>;
}

Async atoms:

tsx

const usersAtom = atom(async () => {
  const response = await fetch('/api/users');
  return response.json();
});

function Users() {
  const [users] = useAtom(usersAtom);
  return <UserList users={users} />;
}

Comparison Matrix

Solution	Best For	Pros	Cons
useState	Local state	Simple, built-in	Limited to component
Context	Simple global state	Built-in, no deps	Can cause re-renders
Zustand	Complex client state	Minimal, fast	Smaller ecosystem
Redux Toolkit	Large apps, teams	Powerful, DevTools	Verbose, learning curve
TanStack Query	Server state	Caching, sync	Not for client state
Jotai	Atomic state	Fine-grained, modern	Smaller ecosystem

Common Patterns

Combining Solutions

TanStack Query + Zustand:

tsx

// Server state with TanStack Query
const { data: users } = useQuery(['users'], fetchUsers);

// Client state with Zustand
const selectedUserId = useStore((state) => state.selectedUserId);

Context + TanStack Query:

tsx

function AuthProvider({ children }) {
  const { data: user } = useQuery(['me'], fetchCurrentUser);
  
  return (
    <AuthContext.Provider value={{ user }}>
      {children}
    </AuthContext.Provider>
  );
}

Form State

Controlled with useState:

tsx

function Form() {
  const [values, setValues] = useState({ name: '', email: '' });
  
  const handleSubmit = (e) => {
    e.preventDefault();
    api.submit(values);
  };
  
  return (
    <form onSubmit={handleSubmit}>
      <input
        value={values.name}
        onChange={e => setValues(prev => ({ ...prev, name: e.target.value }))}
      />
    </form>
  );
}

With form library:

tsx

import { useForm } from 'react-hook-form';

function Form() {
  const { register, handleSubmit } = useForm();
  
  const onSubmit = (data) => api.submit(data);
  
  return (
    <form onSubmit={handleSubmit(onSubmit)}>
      <input {...register('name')} />
    </form>
  );
}

Troubleshooting

Context causing re-renders:

Split into multiple contexts
Use useMemo for context value
Consider Zustand instead

Stale data in TanStack Query:

Adjust staleTime and cacheTime
Use refetchInterval for polling
Invalidate queries after mutations

Redux boilerplate:

Use Redux Toolkit (not legacy Redux)
Use createSlice for reducers
Use createAsyncThunk for async

State updates not reflecting:

Check if mutating state directly
Use functional updates
Verify dependencies in useEffect

state-management-advisor

NPX Install

Tags

SKILL.md Content

State Management Advisor

Quick Start

Instructions

Decision Tree

Local State (useState)

React Context

Zustand

Redux Toolkit

TanStack Query (React Query)

Jotai

Comparison Matrix

Common Patterns

Combining Solutions

Form State

Troubleshooting