What is Redux ?

Redux is a popular JavaScript library for managing the state of an application. It is commonly used in conjunction with React, but can be used with other view libraries as well. Redux provides a predictable and centralized way to manage the state of an application, making it easier to debug and maintain.

In Redux, the state of an application is stored in a single object called the store. The store is managed by a reducer function, which receives actions from the application and updates the store accordingly. Actions are plain JavaScript objects that describe what happened in the application. They are typically created by action creator functions, which return the action object with a type and any necessary data.

Here's an example of how Redux might be used in a React application:

javascriptCopy code// Define the initial state of the application
const initialState = {
  count: 0
};

// Define the reducer function
function reducer(state = initialState, action) {
  switch (action.type) {
    case 'INCREMENT':
      return { count: state.count + 1 };
    case 'DECREMENT':
      return { count: state.count - 1 };
    default:
      return state;
  }
}

// Create the store
const store = Redux.createStore(reducer);

// Define the actions
function increment() {
  return { type: 'INCREMENT' };
}

function decrement() {
  return { type: 'DECREMENT' };
}

// Use the store in a React component
function Counter() {
  const [state, dispatch] = React.useReducer(store.dispatch);

  return (
    <div>
      <p>Count: {state.count}</p>
      <button onClick={() => dispatch(increment())}>Increment</button>
      <button onClick={() => dispatch(decrement())}>Decrement</button>
    </div>
  );
}

In this example, we define an initial state object with a count property of 0. We then define a reducer function that takes an action object and updates the state accordingly. The reducer function handles two types of actions: INCREMENT and DECREMENT, which increase and decrease the count value, respectively.

We create the store using the Redux.createStore() function and pass in the reducer function. We then define two action creator functions, increment() and decrement(), which return the appropriate action objects.

Finally, we use the store in a React component called Counter. We use the React.useReducer() hook to get the current state and dispatch function from the store. We render the current count value and two buttons that dispatch the increment() and decrement() actions when clicked.