React Redux Web Development Guide

React Redux is a popular library for managing state in JavaScript applications, especially those using React. It combines the power of React with the state management capabilities of Redux. This guide will help you get started with React Redux and understand its core concepts.

Core Concepts

State: Centralized state management is the cornerstone of Redux. It allows you to maintain the state of your application in a single, immutable object.
Actions: Actions are payloads of information that send data from your application to your store. They are the only source of information for the store.
Reducers: Reducers are functions that take the current state and an action, and return the next state. They are the heart of Redux, where the actual logic for changing the state lives.

Getting Started

Install Redux and React-Redux: To get started, you need to install Redux and React-Redux. You can do this using npm or yarn.
```
npm install redux react-redux
```
or
```
yarn add redux react-redux
```

Create a Store: Create a Redux store to hold the state of your application.

import { createStore } from 'redux';
import rootReducer from './reducers';

const store = createStore(rootReducer);

Connect React to Redux: Use the Provider component from React-Redux to wrap your root component and make the Redux store available to all components in your application.

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

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

Create a Reducer: Create a reducer function that will handle changes to the state based on actions.

const initialState = {
  count: 0
};

const counterReducer = (state = initialState, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return {
        ...state,
        count: state.count + 1
      };
    case 'DECREMENT':
      return {
        ...state,
        count: state.count - 1
      };
    default:
      return state;
  }
};

Dispatch Actions: Dispatch actions to your store to update the state.
```
store.dispatch({ type: 'INCREMENT' });
```
Use Selectors: Selectors are functions that extract a piece of state from the Redux store. They are useful for getting specific pieces of data from the store.
```
const getCount = state => state.count;
```

Connect Components: Use the connect function from React-Redux to connect your components to the Redux store.

import { connect } from 'react-redux';

const Counter = ({ count, increment, decrement }) => (
  <div>
    <p>Count: {count}</p>
    <button onClick={increment}>Increment</button>
    <button onClick={decrement}>Decrement</button>
  </div>
);

const mapStateToProps = state => ({
  count: getCount(state)
});

const mapDispatchToProps = dispatch => ({
  increment: () => dispatch({ type: 'INCREMENT' }),
  decrement: () => dispatch({ type: 'DECREMENT' })
});

export default connect(mapStateToProps, mapDispatchToProps)(Counter);

React Redux Web Development Guide

Core Concepts

Getting Started

Further Reading