redux toolkit

                                    import {createAction, createReducer} from '@reduxjs/toolkit ;
//Action
const add = createAction('add');
//Reducer
const Reducer = createReducer(initialState= 0, (builder)=>{
  builder.addCase(add, (state,action) => state + 1)
})

                                    import { createSlice } from '@reduxjs/toolkit'
// Slice
const slice = createSlice({
  name: 'user',
  initialState: {
    user: null,
  },
  reducers: {
    loginSuccess: (state, action) => {
      state.user = action.payload;
    },
    logoutSuccess: (state, action) =>  {
      state.user = null;
    },
  },
});
export default slice.reducer
// Actions
const { loginSuccess, logoutSuccess } = slice.actions
export const login = ({ username, password }) => async dispatch => {
  try {
    // const res = await api.post('/api/auth/login/', { username, password })
    dispatch(loginSuccess({username}));
  } catch (e) {
    return console.error(e.message);
  }
}
export const logout = () => async dispatch => {
  try {
    // const res = await api.post('/api/auth/logout/')
    return dispatch(logoutSuccess())
  } catch (e) {
    return console.error(e.message);
  }
}

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

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

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

export const selectCount = state => state.counter.value;

export default counterSlice.reducer;