What does store do in Redux?

ReactJunior~1 min read

What `store` is in Redux

The store is an object that:

holds the entire application state,

lets you read the current state,

lets you update it via dispatch(action),

notifies subscribers (subscribe) about changes.

You can think of the store as the single source of truth: the entire application state is kept right there.

How to create a store

javascript

import { createStore } from "redux";
import { counterReducer } from "./counterReducer";

const store = createStore(counterReducer);

createStore() takes a reducer: a function that controls how the state is updated for different actions.

What the store does

Method	Purpose
`getState()`	Returns the current state
`dispatch(action)`	Sends an action to the reducer to change the state
`subscribe(listener)`	Subscribes a component or function to changes
`replaceReducer(nextReducer)`	Swaps the reducer on the fly (rarely used)

Example

javascript

// 1. Reducer
function counterReducer(state = { count: 0 }, action) {
  switch (action.type) {
    case "INCREMENT":
      return { count: state.count + 1 };
    case "DECREMENT":
      return { count: state.count - 1 };
    default:
      return state;
  }
}

// 2. Create the store
import { createStore } from "redux";
const store = createStore(counterReducer);

// 3. Subscribe to updates
store.subscribe(() => {
  console.log("State changed:", store.getState());
});

// 4. Dispatch actions
store.dispatch({ type: "INCREMENT" });
store.dispatch({ type: "INCREMENT" });
store.dispatch({ type: "DECREMENT" });

What happens:

dispatch sends an action;
The store calls reducer(state, action);
The reducer returns a new state;
The store saves it and notifies all subscribers;
Components receive the new state and re-render.

Store in a React application

Usually used together with react-redux:

javascript

import { Provider, useSelector, useDispatch } from "react-redux";
import { store } from "./store";

function Counter() {
  const count = useSelector(state => state.count);
  const dispatch = useDispatch();

  return (
    <>
      <p>{count}</p>
      <button onClick={() => dispatch({ type: "INCREMENT" })}>+</button>
    </>
  );
}

function App() {
  return (
    <Provider store={store}>
      <Counter />
    </Provider>
  );
}

Here Provider makes the store available to all components, and the useSelector and useDispatch hooks let you work with it.

Summary

What the store does	In short
Holds the state	The entire application state in one place
Manages changes	Updates the state through the `reducer`
Notifies listeners	Notifies on every change
Integrates with React	Through `<Provider>` and the `useSelector` / `useDispatch` hooks

In short:

The store is the "single brain" of a Redux application: it knows the entire state, listens for actions, calls reducers, and updates the interface.

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What does store do in Redux?

#What store is in Redux

#How to create a store

#What the store does

#Example

#Store in a React application

#Summary

Short Answer

What `store` is in Redux

How to create a store

What the store does

Example

Store in a React application

Summary