react-native-template-by-nh/template/src/store/counterSlice/index.ts

React Native Template for a quick start with TypeScript using best existing libraries and scalable structure

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

export interface CounterState {
  value: number;
}

const initialState: CounterState = {
  value: 0,
};

export const counterSlice = createSlice({
  name: 'counter',
  initialState,
  reducers: {
    increment: state => {
      // Redux Toolkit allows us to write "mutating" logic in reducers. It
      // doesn't actually mutate the state because it uses the Immer library,
      // which detects changes to a "draft state" and produces a brand new
      // immutable state based off those changes
      state.value += 1;
    },
    decrement: state => {
      state.value -= 1;
    },
    incrementByAmount: (state, action: PayloadAction<number>) => {
      state.value += action.payload;
    },
  },
});

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

export default counterSlice.reducer;