React Native Interview Prep Quiz Quiz

Test your knowledge of React Native with these carefully crafted multiple-choice questions. This quiz covers essential concepts, differences from React, development practices, and state management to help you prepare for React Native interviews.

1. Understanding React Native

   Which statement best describes React Native?

   1. A framework for building native mobile applications using JavaScript and React.
   2. A database for storing mobile app data.
   3. A tool exclusively for web development.
   4. A language for creating mobile operating systems.

   Explanation: React Native is a popular framework that enables developers to build native mobile apps using JavaScript and React principles. It is not a language for mobile operating systems, which is what option B incorrectly suggests. Option C is wrong because React Native is focused on mobile, not just web. Option D incorrectly identifies React Native as a database.

2. React vs. React Native

   How does React Native differ from standard React?

   1. React Native compiles to native code, while React renders to the web's virtual DOM.
   2. React Native uses TypeScript by default, while React uses Python.
   3. React Native does not support components.
   4. React Native is only used for web, not mobile platforms.

   Explanation: React Native compiles JavaScript to native code, allowing mobile apps to feel truly native, unlike React which manipulates the web's virtual DOM. Option B is incorrect since React Native is specifically for mobile apps. Option C is wrong because neither defaults to TypeScript or Python. Option D is incorrect because components are central to both.

3. Cross-platform Compatibility

   What is the main method used by React Native to provide cross-platform app development?

   1. Using a single JavaScript codebase that is compiled to native code for each platform.
   2. Storing user data in the cloud exclusively.
   3. Creating separate codebases for Android and iOS.
   4. Building apps only using HTML and CSS.

   Explanation: React Native permits developers to write one codebase in JavaScript, which is then compiled into native code for both Android and iOS. Option B refers to native development, not React Native. Option C mentions web technologies not used for mobile native apps, and option D is unrelated to codebase or cross-platform support.

4. JSX in React Native

   Why is JSX important in React Native development?

   1. JSX manages network requests.
   2. JSX allows developers to describe UIs using HTML-like syntax inside JavaScript.
   3. JSX stores persistent data on mobile devices.
   4. JSX provides built-in navigation libraries.

   Explanation: JSX makes it easier to define what the UI should look like by allowing HTML-like code within JavaScript. Option B confuses JSX with storage, option C mistakes it for navigation functionality, while option D incorrectly associates it with network operations.

5. Understanding Props

   What is the primary function of props in React Native components?

   1. Managing navigation between screens.
   2. Storing data persistently on the device.
   3. Directly modifying a component's state internally.
   4. Passing data and configuration from parent to child components.

   Explanation: Props are used to transmit data and settings from a parent component to its children. Option B confuses them with persistent storage, option C mistakes props for state management, and option D incorrectly links props to navigation.

6. Component State

   In React Native, what is the role of the setState method?

   1. It creates navigation stacks.
   2. It applies custom styles to components.
   3. It updates a component's state and triggers a re-render.
   4. It sends data to the backend server.

   Explanation: The setState method alters a component's state, which automatically causes the UI to update and reflect those changes. Option B is incorrect as setState does not interact with servers. Option C is irrelevant since setState is not for navigation. Option D mistakenly confuses it with styling.

7. AsyncStorage Usage

   For which purpose is AsyncStorage used in a React Native application?

   1. Compiling JavaScript code to native code.
   2. Styling components with advanced CSS.
   3. Storing and retrieving key-value data persistently on the device.
   4. Defining props for child components.

   Explanation: AsyncStorage allows apps to persist small amounts of data, such as user tokens or settings. Option B relates to styling, not storage. Option C is incorrect since AsyncStorage isn't about compiling code. Option D confuses AsyncStorage with component properties.

8. Navigation in React Native

   Which of the following correctly describes navigation handling in React Native apps?

   1. Navigation is typically managed using dedicated navigation libraries.
   2. Navigation requires direct manipulation of the device's file system.
   3. Navigation is handled automatically by AsyncStorage.
   4. Navigation can only be achieved via hardcoded HTML pages.

   Explanation: Navigation in React Native is facilitated through libraries that organize and manage different screens. Option B wrongly involves file system access. Option C incorrectly implies the use of HTML, which is not used in native apps. Option D confuses navigation with storage.

9. Redux State Management

   Why is Redux often used in React Native projects?

   1. It automatically resolves all navigation issues.
   2. It provides a centralized store for predictable state management across the entire app.
   3. It allows direct database access from UI components.
   4. It renders components faster using advanced graphics.

   Explanation: Redux helps manage complex state in a predictable way throughout the app. Option B overstates Redux’s role in rendering. Option C is inaccurate as Redux does not provide database access. Option D wrongly attributes navigation handling to Redux.

10. Native vs. React Native Development

    Compared to native development, what is a key advantage of using React Native?

    1. UI customization is not possible.
    2. Developers write a single codebase for both iOS and Android platforms.
    3. Testing can only be performed on physical devices.
    4. Apps must be written in separate languages for each platform.

    Explanation: A major benefit of React Native is the efficiency gained by using one codebase for multiple platforms. Option B describes native development, not React Native. Option C is incorrect because React Native allows extensive UI customization. Option D is untrue; testing can be done on emulators as well.

11. Hot Reloading Feature

    What does 'hot reloading' provide in React Native development?

    1. It automatically optimizes images for mobile screens.
    2. It disables debug logging by default.
    3. It secures user data with automatic encryption.
    4. It allows developers to see code changes instantly without fully restarting the app.

    Explanation: Hot reloading saves time by updating the app with changes in code immediately. Option B is about images and not related to hot reloading. Option C relates to security, and Option D involves logging, neither of which are features of hot reloading.

12. Immutability of Props

    Why are props considered immutable in React Native components?

    1. Because they can be dynamically changed by the component itself.
    2. Because they should not be modified by the receiving child component.
    3. Because they are automatically encrypted.
    4. Because they are stored in device memory permanently.

    Explanation: Props are passed from parent to child and must not be altered by the child to ensure predictable data flow. Option B confuses immutability with persistence. Option C mistakenly attributes security properties, and Option D is false since components cannot modify their own props.

13. Native Look and Feel

    What allows a React Native app to achieve a platform’s native look and feel?

    1. Avoiding the use of any JavaScript altogether.
    2. Storing only data and not rendering any UI.
    3. Relying only on HTML elements for the UI.
    4. Using native UI components for rendering on each platform.

    Explanation: React Native bridges JavaScript code to native UI components, making the app look and feel like a true native app. Option B is incorrect, since HTML is not used for rendering in native mobile apps. Option C is wrong because React Native relies on JavaScript. Option D overlooks the essential part of user interface rendering.

14. Component Reusability

    How does React Native support scalable large-scale application design?

    1. By limiting the number of screens an app can have.
    2. By encouraging the use of modular, reusable components.
    3. By storing all logic in a single function.
    4. By forbidding use of third-party libraries.

    Explanation: Reusable components allow developers to manage complex interfaces and scale applications efficiently. Option B is poor practice that leads to unmanageable code. Option C is incorrect since there’s no such limit, and option D is false as React Native supports many libraries.

15. Data Flow Principle

    Which best describes the data flow direction for props in React Native?

    1. Props can only flow from child to parent components.
    2. Props are bidirectionally synchronized by default.
    3. Props flow unidirectionally from parent to child components.
    4. Props are stored in the navigation stack.

    Explanation: The data flow for props is unidirectional, ensuring predictable communication from parent to child. Option B incorrectly reverses the flow, Option C misrepresents the default behavior in React, and Option D confuses props with navigation data.

16. Purpose of the Virtual DOM

    How does React's use of the virtual DOM differ from rendering in React Native?

    1. React Native uses the virtual DOM for server-side authentication.
    2. React uses the virtual DOM to update browser UIs, while React Native converts elements to native components.
    3. The virtual DOM is only used for persistent device storage.
    4. Both use the virtual DOM to render in a browser environment.

    Explanation: While React manipulates the virtual DOM to efficiently update web UIs, React Native translates components to native views for each platform. Option B wrongly claims both use the virtual DOM for browsers. Option C confuses the virtual DOM with storage, and Option D is unrelated to server-side authentication.