React Native Interview Quiz: Key Concepts u0026 Best Practices Quiz

Test your understanding of core React Native concepts and interview topics with this 15-question multiple-choice quiz. Topics include state, props, hooks, navigation, lists, layout techniques, and common components used in React Native development.

1. React Native Overview

   Which of the following best describes React Native?

   1. A JavaScript framework for building native mobile apps using React.
   2. A UI toolkit for desktop applications.
   3. A backend framework for building APIs.
   4. A CSS library for responsive web design.

   Explanation: React Native is an open-source framework that enables developers to build mobile apps using JavaScript and React. It bridges JavaScript with native mobile components. The other options refer either to web or desktop technologies, or backend frameworks, which are not related to React Native's focus.

2. React Native vs ReactJS

   How does React Native differ from ReactJS when rendering user interfaces?

   1. Both use only HTML and CSS for rendering.
   2. React Native uses native UI components, while ReactJS renders HTML in a browser.
   3. React Native renders only on desktop devices.
   4. ReactJS runs exclusively on mobile platforms.

   Explanation: React Native targets mobile platforms by mapping components to native UI elements, while ReactJS is meant for web apps rendered in browsers using HTML and CSS. The other options misrepresent platforms or the rendering process in both frameworks.

3. Core Components

   Which React Native component is typically used to display editable text input fields?

   1. Image
   2. TextInput
   3. View
   4. TouchableHighlight

   Explanation: TextInput is specifically designed for entering and editing text in React Native. Image is for displaying images, TouchableHighlight is for pressable elements, and View is a container for layout purposes but not for text input.

4. JSX Syntax

   What is the main purpose of JSX in React Native development?

   1. It is a tool for handling HTTP requests.
   2. It allows writing layout code that looks like HTML inside JavaScript files.
   3. It manages application navigation.
   4. It encrypts sensitive data stored locally.

   Explanation: JSX stands for JavaScript XML and lets developers write code similar to HTML within JavaScript, which is then converted into native components. It does not deal with HTTP requests, data encryption, or navigation directly.

5. State Management

   In React Native, what is the primary use of state within a component?

   1. To define external properties passed from a parent component.
   2. To store data that can change and update the UI accordingly.
   3. To handle navigation between screens.
   4. To store static configuration constants.

   Explanation: State is used for dynamic data that affects rendering. Props are for passing data from parent to child, navigation is typically handled with routers or libraries, and constants should not be stored in state.

6. Props vs State

   What is a key difference between props and state in React Native?

   1. Props are passed from parent to child; state is managed internally within a component.
   2. State manages navigation, while props handle persistent storage.
   3. Props mutate asynchronously; state is immutable.
   4. State is visible to all components globally; props are hidden.

   Explanation: Props are external and read-only, allowing data flow from parent to child; state is internal and meant for a component's own data. Props do not mutate nor manage storage or global visibility, which the other options incorrectly state.

7. Hooks in React Native

   What does the useEffect hook enable you to do in a functional component?

   1. Directly update state without setState.
   2. Create navigators between screens.
   3. Define global constants.
   4. Run side effects like data fetching after rendering.

   Explanation: useEffect is intended for handling side effects such as API calls, timers, or subscriptions after component render. It does not directly update state, handle navigation, or define global constants.

8. Navigation Between Screens

   What is a typical method for navigating to another screen in a React Native app?

   1. Calling setState with a new route name.
   2. Using localStorage to change screens.
   3. Directly importing the target screen and rendering it.
   4. Using navigation.navigate('ScreenName') with a navigation library.

   Explanation: Navigation libraries provide the navigation.navigate method for screen transitions. setState does not handle navigation, localStorage is not for screen logic, and direct imports do not handle navigation context.

9. Lists: ScrollView vs FlatList

   Why is FlatList recommended over ScrollView for long lists in React Native?

   1. FlatList only renders visible items, improving performance.
   2. FlatList cannot be scrolled vertically.
   3. ScrollView supports pagination out-of-the-box.
   4. ScrollView is more memory efficient than FlatList.

   Explanation: FlatList optimizes resource usage by rendering only visible list items, making it suitable for large lists. ScrollView renders all child elements at once and is not as efficient. FlatList supports vertical and horizontal scrolling, and ScrollView is less memory efficient as it mounts all children.

10. Layout: Flexbox

    How does Flexbox help when designing layouts in React Native?

    1. It stores large files in local storage.
    2. It allows flexible arrangement of components for responsive design.
    3. It automatically fetches data from APIs.
    4. It encrypts user credentials.

    Explanation: Flexbox in React Native helps align and distribute space efficiently, allowing responsive layouts. It does not fetch data, manage storage, or handle encryption, which are unrelated to layout design.

11. Data Persistence

    What is AsyncStorage primarily used for in React Native?

    1. Storing small key-value data like tokens or preferences locally.
    2. Persisting navigation state between screens.
    3. Running background tasks.
    4. Storing large image and video files.

    Explanation: AsyncStorage lets you store simple data like user tokens or preferences. It's not meant for large files, navigation persistence, or running background jobs.

12. Touchable Components

    What feature does TouchableOpacity provide for React Native interfaces?

    1. Makes components respond visually to touch by changing opacity.
    2. Loads data from an external API.
    3. Handles device permissions automatically.
    4. Encrypts sensitive user input.

    Explanation: TouchableOpacity visually indicates user interaction by changing opacity, enhancing user experience for pressable elements. It doesn't handle encryption, data loading, or permissions.

13. Safe Area Handling

    Why would you use SafeAreaView in a React Native project?

    1. To prevent UI elements from overlapping device notches or status bars.
    2. To improve data encryption speed.
    3. To enable automatic screen transitions.
    4. To fetch user location data.

    Explanation: SafeAreaView ensures the app's content is rendered within safe screen boundaries, avoiding overlaps with notches or system UI. Other options do not relate to UI layout or safe areas.

14. Component Types

    What is a key distinction between a class component and a functional component in React Native?

    1. Functional components cannot render any UI elements.
    2. Only class components can handle user input.
    3. Functional components are exclusively used in web development.
    4. Class components use lifecycle methods; functional components rely on hooks.

    Explanation: Class components utilize lifecycle methods, while functional components use hooks for state and side effects. Functional components can render UI and handle input, and their use isn't limited to web development.

15. Refs and Mutable Values

    For what purpose is the useRef hook typically used in React Native?

    1. To fetch data from a server asynchronously.
    2. To store state that triggers UI re-renders automatically.
    3. To create references that persist between renders, such as accessing a TextInput.
    4. To navigate between app screens.

    Explanation: useRef enables you to maintain references that persist across rerenders and don't cause rerenders if changed. It’s not for fetching data, navigation, or stateful rerendering.

16. Form Handling

    How are forms commonly handled in React Native?

    1. By saving values directly into localStorage upon entry.
    2. By using TextInput components with state variables to manage their values.
    3. By connecting form fields only to props without state.
    4. By directly modifying the DOM with document.getElementById.

    Explanation: Form inputs are managed by controlling their value with state hooks like useState. Direct DOM manipulation is not part of React Native, values aren’t typically stored directly in localStorage, and relying only on props doesn't support input state changes.