Redux Toolkit Implementation Best Practices

Introduction

Redux Toolkit (RTK) is the official, opinionated, batteries-included toolset for efficient Redux development. It simplifies common Redux use cases, reduces boilerplate, and enforces best practices. However, even with RTK, developers can still fall into anti-patterns or inefficient implementations if they don’t follow recommended practices.

In this post, we’ll explore key best practices for structuring, organizing, and optimizing Redux Toolkit in your applications. Whether you're migrating from legacy Redux or starting fresh, these guidelines will help you build maintainable and performant state management.

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1. Organizing Your Store with Slices

Redux Toolkit introduces the createSlice function, which automatically generates action creators and reducers. Properly structuring your slices ensures readability and scalability.

Best Practices for Slices

• Group Related Logic: Each slice should manage a specific domain of your application state (e.g., userSlice, cartSlice).
• Use Meaningful Names: Prefix actions and selectors with the slice name (e.g., user/login, cart/addItem).
• Keep State Shape Flat: Avoid deeply nested state structures to simplify updates.

Here’s an example of a well-structured slice:

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

interface UserState {  
  id: string | null;  
  name: string | null;  
  isLoggedIn: boolean;  
}  

const initialState: UserState = {  
  id: null,  
  name: null,  
  isLoggedIn: false,  
};  

const userSlice = createSlice({  
  name: 'user',  
  initialState,  
  reducers: {  
    login(state, action: PayloadAction<{ id: string; name: string }>) {  
      state.id = action.payload.id;  
      state.name = action.payload.name;  
      state.isLoggedIn = true;  
    },  
    logout(state) {  
      state.id = null;  
      state.name = null;  
      state.isLoggedIn = false;  
    },  
  },  
});  

export const { login, logout } = userSlice.actions;  
export default userSlice.reducer;

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2. Leveraging createAsyncThunk for Async Logic

Handling side effects (e.g., API calls) is a common Redux requirement. RTK’s createAsyncThunk simplifies this by abstracting the loading/error states.

Best Practices for Async Thunks

• Use Descriptive Action Types: Follow the convention sliceName/actionType (e.g., user/fetchUserById).
• Handle Errors Gracefully: Use rejectWithValue to return structured error responses.
• Keep Thunks Focused: Each thunk should handle a single async operation.

Example:

import { createAsyncThunk } from '@reduxjs/toolkit';  
import { fetchUser } from '../api/userApi';  

export const fetchUserById = createAsyncThunk(  
  'user/fetchUserById',  
  async (userId: string, { rejectWithValue }) => {  
    try {  
      const response = await fetchUser(userId);  
      return response.data;  
    } catch (err) {  
      return rejectWithValue(err.response.data);  
    }  
  }  
);  

// In the slice's extraReducers:  
extraReducers: (builder) => {  
  builder  
    .addCase(fetchUserById.pending, (state) => {  
      state.loading = true;  
    })  
    .addCase(fetchUserById.fulfilled, (state, action) => {  
      state.loading = false;  
      state.user = action.payload;  
    })  
    .addCase(fetchUserById.rejected, (state, action) => {  
      state.loading = false;  
      state.error = action.payload;  
    });  
},

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3. Optimizing Performance with Selectors

Selectors compute derived data from the Redux store. RTK works seamlessly with reselect for memoized selectors.

Best Practices for Selectors

• Use createSelector for Memoization: Prevents unnecessary recalculations.
• Keep Selectors Close to Slices: Define them in the same file as the slice.
• Avoid Over-Fetching: Select only the data needed by the component.

Example:

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

const selectUserState = (state) => state.user;  

export const selectUserName = createSelector(  
  selectUserState,  
  (user) => user.name  
);  

export const selectIsLoggedIn = createSelector(  
  selectUserState,  
  (user) => user.isLoggedIn  
);

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4. Configuring the Store for Scalability

A well-configured store ensures maintainability as your app grows.

Best Practices for Store Setup

• Use configureStore: It includes Redux DevTools and middleware by default.
• Apply Middleware Judiciously: Only add necessary middleware (e.g., redux-logger in development).
• Enable Serializability Checks: RTK includes middleware to detect non-serializable values.

Example store configuration:

import { configureStore } from '@reduxjs/toolkit';  
import userReducer from './userSlice';  
import cartReducer from './cartSlice';  

const store = configureStore({  
  reducer: {  
    user: userReducer,  
    cart: cartReducer,  
  },  
  middleware: (getDefaultMiddleware) =>  
    getDefaultMiddleware({  
      serializableCheck: {  
        ignoredActions: ['user/specialAction'],  
      },  
    }),  
  devTools: process.env.NODE_ENV !== 'production',  
});  

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

export default store;

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Conclusion

Redux Toolkit significantly reduces Redux boilerplate while enforcing best practices. By organizing slices logically, handling async flows with createAsyncThunk, optimizing selectors, and configuring the store properly, you can build scalable and maintainable state management.

Adopting these practices early ensures your Redux codebase remains clean, performant, and easy to debug as your application grows. For further reading, explore the Redux Toolkit documentation and experiment with these patterns in your projects.

Happy coding! 🚀