What is Redux used for?

Redux is used for state management in JavaScript applications, especially in SPA (Single Page Applications). It provides a predictable container for storing state, making its changes transparent and easy to debug.

Main goals of Redux:

• Centralized state storage: All application state is stored in a single object - store.
• Predictability of changes: State is changed only through special actions and pure functions (reducers).
• Debugging and testing: Thanks to predictability, it is easy to track and debug state changes. Redux developer tools allow viewing all actions and state at any moment.
• Managing complex state: Helps organize and manage complex state in large applications.
• Performance improvement (optional): Proper use of Redux can help optimize rendering, avoiding unnecessary component re-renders.

Key concepts of Redux:

• Store: An object that holds the entire application state.
• Actions: Simple JavaScript objects describing an event that occurred.
• Reducers: Pure functions that take the current state and an action, and return a new state.
• Dispatch: The store method for sending actions.
• Middleware: Intermediary software that can be used to extend Redux capabilities, for example, for handling asynchronous actions.

// Example of a simple Reducer
function counterReducer(state = 0, action) {
  switch (action.type) {
    case 'INCREMENT':
      return state + 1;
    case 'DECREMENT':
      return state - 1;
    default:
      return state;
  }
}