Understanding Redux Store, Actions and Reducers in React

In a Redux-powered application, the architecture revolves around three main concepts: the Redux store, actions, and reducers. Let's delve deeper into each of these concepts and see how they work together.

Redux Store

The Redux store is a single source of truth that holds the complete state of your application. It's essentially a JavaScript object that contains the data representing the entire application state. You create the store using the createStore function from the Redux library.


Actions are plain JavaScript objects that describe something that happened in the application. They carry a type field that indicates the type of action being performed, and additional data can be included as well. Actions are created using action creators, which are functions that return action objects. For example:

// Action Types
const ADD_TODO = 'ADD_TODO';

// Action Creator
const addTodo = (text) => {
  return {
    type: ADD_TODO,
    payload: text


Reducers specify how the application's state changes in response to actions. A reducer is a pure function that takes the current state and an action as arguments and returns a new state. Reducers are combined into a single root reducer using the combineReducers function. Here's a simple example:

// Reducer
const todosReducer = (state = [], action) => {
  switch (action.type) {
    case ADD_TODO:
      return [...state, action.payload];
      return state;

// Combine Reducers
const rootReducer = combineReducers({
  todos: todosReducer,
  // ...other reducers

Working Together

When you dispatch an action using the dispatch function, Redux forwards the action to all the reducers. Each reducer checks if the action's type matches its own and updates the relevant part of the state accordingly. The updated state is then stored in the Redux store, and any connected components re-render based on the new state.

Example Scenario

Imagine a todo list application. When a user adds a new todo, an action is dispatched with the type ADD_TODO and the text of the todo as payload. The todos reducer receives this action, adds the new todo to the state, and returns the updated state.


Understanding how the Redux store, actions, and reducers interact is crucial for effective state management. This architecture ensures a clear separation of concerns and makes it easy to manage complex application states. As you continue to develop with Redux, these concepts will form the foundation of your state management strategy.