What is the redux toolkit?

Redux Toolkit is the official, opinionated, batteries-included toolset for efficient Redux development. It provides utilities to simplify common Redux use cases, such as store setup, reducer creation, and asynchronous logic handling.

Function and Utils

Redux Toolkit includes various functions and utilities to streamline Redux development, such as configureStore, createSlice, createAsyncThunk, and createEntityAdapter.

Configure Store

configureStore is a function provided by Redux Toolkit to set up a Redux store with sensible defaults and additional middleware.

import { configureStore } from '@reduxjs/toolkit'; 
import rootReducer from './reducers';

const store = configureStore({
 reducer: rootReducer, 
 devTools: process.env.NODE_ENV !== 'production' 
});

export default store;

Provider

Provider access the Redux store through a React Application

import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import store from './store';
import App from './App';

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

createSlice

createSlice to create Redux state slices with reducers and action creators.

import { 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 default counterSlice.reducer;

useDispatch

useDispatch for accessing the dispatch function

import React from 'react';
import { useDispatch } from 'react-redux';
import { increment, decrement } from './counterSlice';

const Counter = () => {
  const dispatch = useDispatch();

  return (
    <div>
      <button onClick={() => dispatch(increment())}>Increment</button>
      <button onClick={() => dispatch(decrement())}>Decrement</button>
    </div>
  );
};

export default Counter;

useSelector

useSelector for accessing the Redux store state

import React from 'react';
import { useSelector } from 'react-redux';

const CounterDisplay = () => {
  const count = useSelector(state => state.counter.value);

  return <div>Count: {count}</div>;
};

export default CounterDisplay;

createAsyncThunk

• generates async action creator

• take action type string as a token

ActionType

it generates three action types a pending, a fulfilled, and a rejected action type.

Async function

an async function as the second argument to createAsyncThunk for asynchronous operation. you can dispatch actions, perform async operations (like API calls), and handle any errors that may occur.

import { createSlice, createAsyncThunk } from '@reduxjs/toolkit';
import { fetchUser } from '../api/userAPI';

export const fetchUserById = createAsyncThunk(
  'users/fetchByIdStatus',
  async (userId, thunkAPI) => {
    const response = await fetchUser(userId);
    return response.data;
  }
);

const userSlice = createSlice({
  name: 'user',
  initialState: {
    data: {},
    status: 'idle',
  },
  reducers: {},
  extraReducers: builder => {
    builder
      .addCase(fetchUserById.pending, state => {
        state.status = 'loading';
      })
      .addCase(fetchUserById.fulfilled, (state, action) => {
        state.status = 'succeeded';
        state.data = action.payload;
      })
      .addCase(fetchUserById.rejected, (state, action) => {
        state.status = 'failed';
        state.error = action.error.message;
      });
  },
});

export default userSlice.reducer;