React Redux Quiz ( Beginner ) - All Questions

This easy-level React Redux quiz is designed for beginners who want to understand state management fundamentals using Redux in React applications. It covers core concepts like store, actions, reducers, and basic React-Redux integration in a clear, interview-friendly way.

Question 1: What problem does Redux primarily solve?

Routing
State management
Styling
API calls

Explanation: Redux is used for predictable state management.

Question 2: What is Redux?

A database
A UI library
A state management library
A CSS framework

Explanation: Redux manages application state in a predictable way.

Question 3: Which part of Redux holds the application state?

Reducer
Action
Store
Middleware

Explanation: The Redux store holds the entire application state.

Question 4: What is an action in Redux?

A function
An object describing what happened
A reducer
A component

Explanation: Actions are plain objects that describe state changes.

Question 5: Which property is mandatory in every Redux action?

payload
data
type
state

Explanation: Every action must have a type field.

Question 6: What is a reducer in Redux?

A component
A function that updates state
An API handler
A hook

Explanation: Reducers calculate new state based on actions.

Question 7: Reducers should always be:

Async
Pure functions
Class-based
Mutable

Explanation: Reducers must be pure and predictable.

Question 8: What does combineReducers do?

Merges components
Combines actions
Combines multiple reducers
Combines stores

Explanation: It combines multiple reducers into one root reducer.

Question 9: How many stores should a Redux app have?

Multiple
One
One per component
Unlimited

Explanation: Redux follows a single store principle.

Question 10: Which method is used to send an action to the store?

send()
emit()
dispatch()
update()

Explanation: dispatch() sends actions to the Redux store.

Question 11: Which library connects React with Redux?

redux-core
react-redux
redux-react
redux-dom

Explanation: react-redux provides bindings between React and Redux.

Question 12: What does Provider do in React Redux?

Creates store
Provides store to components
Dispatches actions
Handles routing

Explanation: Provider makes the Redux store available to components.

Question 13: Which hook is used to read data from Redux store?

useDispatch
useSelector
useReducer
useStore

Explanation: useSelector reads data from the Redux store.

Question 14: Which hook is used to dispatch actions?

useSelector
useReducer
useDispatch
useEffect

Explanation: useDispatch returns the dispatch function.

Question 15: What format is Redux state usually stored in?

XML
String
JSON object
Array only

Explanation: Redux state is typically a plain JavaScript object.

Question 16: Can Redux be used without React?

Yes
No
Only with hooks
Only with classes

Explanation: Redux is framework-agnostic.

Question 17: What is the role of middleware in Redux?

Update UI
Handle side effects
Create reducers
Store state

Explanation: Middleware handles async logic and side effects.

Question 18: Which middleware is commonly used for async actions?

redux-sync
redux-watcher
redux-thunk
redux-core

Explanation: redux-thunk allows async logic in actions.

Question 19: What does redux-thunk allow actions to return?

Objects only
Strings
Functions
Reducers

Explanation: redux-thunk allows returning functions from actions.

Question 20: What should reducers never do?

Return state
Mutate state directly
Handle actions
Use switch

Explanation: Reducers must not mutate state directly.

Question 21: Which tool helps debug Redux state changes?

Redux Logger
Redux DevTools
React Inspector
State Viewer

Explanation: Redux DevTools helps inspect actions and state.

Question 22: What does mapStateToProps do?

Maps actions
Maps store state to props
Maps components
Maps routes

Explanation: It maps Redux state to component props.

Question 23: What does mapDispatchToProps do?

Maps state
Maps reducers
Maps dispatch to props
Maps store

Explanation: It maps dispatch functions to component props.

Question 24: Which Redux principle ensures predictable state?

Multiple stores
Mutable state
Single source of truth
Component state

Explanation: Single source of truth keeps state predictable.

Question 25: Which function creates a Redux store?

makeStore()
createStore()
initStore()
buildStore()

Explanation: createStore() creates the Redux store.

Question 26: Redux state updates are:

Synchronous
Asynchronous
Random
Automatic

Explanation: Reducers update state synchronously.

Question 27: What is Redux Toolkit?

A testing library
Official Redux helper library
Middleware only
Routing tool

Explanation: Redux Toolkit simplifies Redux development.

Question 28: Which function is used to create reducers in Redux Toolkit?

createReducer
buildReducer
makeReducer
initReducer

Explanation: createReducer helps write reducers easily.

Question 29: What does createSlice do?

Creates store
Creates reducer and actions
Creates middleware
Creates component

Explanation: createSlice generates reducer and action creators.

Question 30: Which Redux Toolkit feature allows writing mutable logic safely?

Thunk
Immer
Logger
DevTools

Explanation: Immer allows safe mutable-style logic.

Question 31: What is the default middleware included in Redux Toolkit?

redux-saga
redux-thunk
redux-observable
redux-sync

Explanation: Redux Toolkit includes thunk by default.

Question 32: What does useSelector return?

Dispatch function
Selected state value
Reducer
Action

Explanation: useSelector returns selected state data.

Question 33: When does a component re-render with useSelector?

On every action
When selected state changes
Only on mount
Never

Explanation: Component re-renders when selected state changes.

Question 34: Redux is best suited for managing:

Local UI state
Global application state
DOM elements
Styles

Explanation: Redux manages global shared state.

Question 35: Which Redux concept describes how state changes?

Actions
Reducers
Middleware
Store

Explanation: Reducers define how state changes.

Question 36: What does dispatch return by default?

State
Action
Undefined
Promise

Explanation: dispatch returns the dispatched action.

Question 37: Which Redux feature helps keep logic reusable?

Components
Slices
Styles
Routes

Explanation: Slices encapsulate related Redux logic.

Question 38: Redux follows which data flow?

Two-way
One-way
Circular
Random

Explanation: Redux uses unidirectional data flow.

Question 39: Which file typically defines Redux actions?

Component file
Action file
Reducer file
CSS file

Explanation: Actions are usually defined in action files or slices.

Question 40: What happens after an action is dispatched?

Reducer runs
Component mounts
Store resets
Middleware stops

Explanation: Reducers run after an action is dispatched.

Question 41: Redux state should be treated as:

Mutable
Read-only
Dynamic
Optional

Explanation: State should never be modified directly.

Question 42: Which hook replaces connect() in modern Redux?

useRedux
useStore
ReduxHook
React Redux hooks

Explanation: React Redux hooks replace connect().

Question 43: Which Redux concept describes an intention to change state?

Reducer
Action
Store
Middleware

Explanation: Actions describe what happened.

Question 44: What does a reducer return?

Action
New state
Dispatch
Promise

Explanation: Reducers return the next state.

Question 45: Redux helps mainly with:

UI rendering
State predictability
Styling
DOM access

Explanation: Redux makes state changes predictable.

Question 46: Which Redux concept listens for dispatched actions?

Component
Reducer
Store
Provider

Explanation: The store receives dispatched actions.

Question 47: Which Redux Toolkit function creates the store easily?

createStore
configureStore
initStore
buildStore

Explanation: configureStore simplifies store setup.

Question 48: Redux state is updated using:

Direct assignment
Reducers
Components
Hooks

Explanation: Reducers are responsible for updating state.

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React Redux Quiz ( Beginner )

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