Redux Toolkit React Counter App

Hi, I'm Ravi. I'm an JavaScript Developer by profession and a Youtuber also, subscribe my channel JavaScript Centric If you are one of the lover of JavaScript.

In this post I will share the basic example of a Counter App implemented using react and redux toolkit.

Why use Redux Toolkit? 🤷‍♂️

Redux toolkit includes all the functions or "tools", you want for a Redux application. At the end of the day, less code and faster setups of Redux in every scenario.

Here's what the Official docs said :

These tools should be beneficial to all Redux users. Whether you're a brand new Redux user setting up your first project, or an experienced user who wants to simplify an existing application, Redux Toolkit can help you make your Redux code better.

Create a react app

Create-react-app gives you a basic React app so don't have to setup React yourself.

npx create-react-app readuxtoolkit_app

Now we need to add react-redux and Redux Toolkit to this app:

npm install --save react-redux @reduxjs/toolkit

You can install react-bootstrap also:

npm install --save react-bootstrap

Folder Structure

We will be following this folder structure. Create two folders app and features inside src folder. Inside app folder create file store.js and inside features folder create two other folders coin and counter.

Steps To Follow

Create a Redux Store
Provide the Redux Store to React Main App.js
Create a Redux State Slice
Add Slice Reducers to the Store
Use Redux State and Actions in React Component
To use redux state in other component use useSelector hook from react-redux

1.First Step is to configure our Store, now this is where you'll see the magic of redux toolkit! Now your redux store src/app/store.js will contains

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

export const store = configureStore({
  reducer: {

  },
})

Here configureStore({}) wraps createStore to provide simplified configuration options and good defaults. It can automatically combine your slice reducers, adds whatever Redux middleware you supply, includes redux-thunk by default, and enables use of the Redux DevTools Extension.

2.Now we need to connect our store to our app or just wrap it with Redux. Import store.js and Provider from react-redux into src/index.js

import { store } from "./app/store";
import { Provider } from "react-redux";

ReactDOM.render(
    <React.StrictMode>
        <Provider store={store}>
            <App />
        </Provider>
    </React.StrictMode>,
    document.getElementById("root")
);

Now start your application with npm start and open up Redux DevTools, you should see @@INIT. Congrats you have setup Redux with React!! 🥳️

3.Third Step is to create a counterSlice.js file inside features/counter folder.

import { createSlice } from '@reduxjs/toolkit'

const initialStateValues = {
  coin: 0,
}

export const counterSlice = createSlice({
  name: 'counter',
  initialState: initialStateValues,
  reducers: {
    increment: (state) => {
      state.coin += 1
    },
    decrement: (state) => {
      state.coin -= 1
    },
    incrementByAmount: (state, action) => {
      state.coin += action.payload
    },
    decrementByAmount: (state, action) => {
      state.coin -=action.payload
    }
  },
})

// Action creators are generated for each case reducer function
export const { increment, decrement, incrementByAmount, decrementByAmount } = counterSlice.actions

export default counterSlice.reducer

Basically createSlice accepts an object of reducer functions, a slice name( in our case slice name is 'counter') and an initialState(here initialStateValues that contains coin) and automatically generates a slice reducer with corresponding action creators and action types.

4.Fourth Step is to Add Slice Reducers to the Store. So update store.js will look like below:

import { configureStore } from '@reduxjs/toolkit';
import counterReducer from './../features/counter/counterSlice';

export const store = configureStore({
  reducer: {
      counter: counterReducer
  },
})

In case if you are using other reduces than you have to use combineReducers from redux as below:

import { configureStore } from "@reduxjs/toolkit";
import counterReducer1 from "./../features/counter/counterSlice1";
import counterReducer2 from "./../features/counter/counterSlice2";

import { combineReducers } from "redux";

const reducer = combineReducers({
  // put all your reducers here!
  counterReducer1,
  counterReducer2,
});

export const store = configureStore({
  reducer,
});

5.To use actions in other component we have to use useDispatch() provided by "react-redux" and used to dispatch our actions like

const dispatch = useDispatch();
now call dispatch action by passing action name inside it.
In features/counter/Counter.js we are using different actions like (increment, decrement, incrementByAmount, decrementByAmount).

import { useDispatch } from "react-redux";
import {
  increment,
  decrement,
  incrementByAmount,
  decrementByAmount,
} from "./counterSlice";
import Button from 'react-bootstrap/Button';
import 'bootstrap/dist/css/bootstrap.min.css';

const Counter = () => {
  const dispatch = useDispatch();
  return (
    <div>
      <hr />
      <Button
        aria-label="Increment value"
        onClick={() => {
          dispatch(increment());
        }}
        variant="success"
        className="mx-2"
      >
        Increase
      </Button>

      <Button
        className="button"
        aria-label="Decrement value"
        onClick={() => {
          dispatch(decrement());
        }}
        variant="danger"
        className="mx-2"
      >
        Decrease
      </Button>

      <Button
        className="button"
        aria-label="Decrement value"
        onClick={() => {
          dispatch(incrementByAmount(10));
        }}
        variant="success"
        className="mx-2"
      >
        IncrementBy 10
      </Button>

      <Button
        className="button"
        aria-label="Decrement value"
        onClick={() => {
          dispatch(decrementByAmount(10));
        }}
        variant="danger"
        className="mx-2"
      >
        DecrementBy 10
      </Button>
    </div>
  );
};
export default Counter;

6.To use redux state in other component use useSelector hook from react-redux like in features/coin/Coin.js.

Remember the name of our reducer we imported in counterSlice.js, that's the name we have to use when using the useSelector() hook.

It receives our state in arguments and then we can extract every other variable in our state with the help of destructuring like below.

import {useSelector} from 'react-redux';
const Coin = () => {
  const {coin} = useSelector((state)=>state.counter);
  return (
    <div style={{paddingTop: '200px'}}>
      <b><big className="value">Coins: {coin}</big></b>
    </div>
  );
};

export default Coin;

Now in your Terminal, to start your React app: