React Native is a JavaScript platform for creating and developing genuine, natively rendering iOS and Android mobile apps. React Native enables JavaScript interfaces for application APIs so that the React Native apps can access system properties such as a location, system settings, phone camera of the user. The main advantage of React native is most of the code developer write can be shared between platforms, React Native makes it easy to simultaneously develop for both Android and iOS.
Part 1 – Basic React Native Interview Questions
This first part covers basic React Native Interview Questions and Answers.
Q1. What is React Native?
Answer:
React Native is a Facebook open source project that allows developers to create mobile cross-platform applications with JavaScript. By using the same design principles, you can build a mobile app using the ReactJS framework for a web application. lets the developer construct a mobile application user interface through the composition of multiple components. There were few options before React native, such as Cordova, an ionic application for hybrid building. Such apps had been built using web technologies but the hybrid application was not a native application and there was no issue with performance. Native reaction solves performance issues, which is why React group has become popular quickly.
Q2. Who Uses React Native?
Answer:
Many popular companies and applications use React Native for mobile app development, including:
- Tesla
- F8
- Skype
These companies use React Native to improve development speed and maintain high app performance.
Q3. What is the Use of WebView in React Native?
Answer:
WebView in React Native is used to display web pages inside a mobile application.
Features of WebView:
- Loads web content directly within the app
- Connects web applications with native applications
- Supports browser-like functionality
- Helps integrate web-based pages into mobile apps
WebView acts as a bridge between web content and native mobile functionality.
Q4. What is Gesture Responder System?
Answer:
The gesture response device controls the lifecycle of your application’s actions. The software decides what the user’s purpose is, and touch can go through many stages.
It helps determine how an application responds to:
- Taps
- Scrolls
- Swipes
- Multi-touch gestures
Multiple concurrent touches can also exist. To allow components to manage these contact interactions without further knowledge regarding their parent or child portion, the touch response system has to be used.
Q5. How to Create a Button by Using the React Native?
Answer:
React native provides a platform-specific Button component. This shows how we can build a basic platform button in Native react. The local device button means that the look and feel of a button depending on whether the program runs on iOS or Android. Title and onPress are two key advocates of the button part. Title props will be used on the button to display text. The callback is onPress props, triggered by the user when he presses the button. This is much like a web browser click case. We can’t design React native’s button part.
Example:
<Button
title=”Click Me”
onPress={() => alert(‘Button Pressed’)}
/>
Important Properties:
- title → Displays text on the button
- onPress → Executes a function when the button is clicked
The button appearance changes depending on whether the app runs on Android or iOS.
Part 2 – React Native Interview Questions (Advanced)
Let us now have a look at the advanced React Native Interview Questions.
Q6. How Virtual DOM Works in React Native?
Answer:
React builds an in-home cache in the data structure, measures the variations resulting and then quickly updates the DOM shown on the browser. It enables developers to write code as if the whole page is displayed on each update when the React libraries just alter subcomponents.
Working Process:
- React creates a virtual representation of the UI.
- When data changes, React compares the new Virtual DOM with the previous one.
- Only changed components are updated efficiently.
Benefits:
- Faster rendering
- Improved performance
- Reduced direct manipulation of UI elements
Q7. How CSS Flexbox is Used to Layout a React Native UI?
Answer:
The display in React native is set to flex by default. Flex is a CSS property that is used to dynamically expand and reduce a variable depending on the space available. The part takes up all the space available if you set flex:1. If a parent element has flex:1, then every element of its child must uniformly allocate the space available. By providing greater value to the flex property, we may adjust the width of the child item.
Example;
<View style={{ flex: 1 }}>
Key Features:
- flex: 1 makes a component occupy available space
- Supports responsive layouts
- Aligns items horizontally and vertically
Common Flexbox Properties:
- flexDirection
- justifyContent
- alignItems
Flexbox helps create dynamic and responsive mobile interfaces.
Q8. What is JSX?
Answer:
JSX is a JavaScript framework for XML embedding. You may claim JSX is a template language to write JavaScript HTML/XML tags. HTML/XML can be written to the JavaScript file with the aid of JSX. JSX enables react feature conditional rendering. The reaction involves the construct stage that converts JSX to JavaScript code that is ultimately executed in the case of a web application or a reaction Native if React Native is used.
Example:
const element = <Text>Hello World</Text>;
Advantages of JSX:
- Simplifies UI creation
- Improves readability
- Supports conditional rendering
JSX code is converted into JavaScript during compilation.
Q9. Which React Native Tool and Skills you Need to Create the Mobile App?
Answer:
One of the main attributes of a system is the developer experience. If it is very difficult and complicated to start with any structure, the group can take a great deal of time to embrace it. This is why React native has made every effort to simplify the first step for the development of apps. To create a mobile app with React Native you need to understand JavaScript principles and CSS design supports React Native app.
Technical Skills:
- JavaScript
- ES6 concepts
- React fundamentals
- Flexbox and CSS styling
- API handling
- Mobile UI design
Tools:
- Visual Studio Code
- Android Studio
- Xcode
- Node.js
Understanding these technologies helps developers build efficient cross-platform applications.
Q10. What are the Advantages of React Native?
Answer:
Props are parameters used at the time of design and restoration to configure a part. Proposals are like arguments passed to a part of a reaction. For instance, Image is a very fundamental component given for displaying an image in React Native library. It embraces a prop called source that regulates the picture that it shows. By modifying the values of props, a part may show different UIs and features. We may argue that props allow the same part in different areas to be used and re-used.
Advantages:
- Cross-platform development
- Faster development cycle
- Reusable components
- Strong community support
- Near-native performance
- Hot Reloading support
- Cost-effective development
Props in React Native
Props are used to pass data from one component to another.
Example:
<Image source={require(‘./image.png’)} />
Props help developers reuse components with different data and functionality.
Q11. What are Hooks in React Native?
Answer:
Hooks in React Native allow developers to use state, lifecycle methods, and reusable logic inside functional components without using class components.
- Common Hooks:
- useState
- useEffect
- useContext
Benefits:
- Cleaner code
- Better state management
- Reusable logic
Q12. What is Hot Reloading in React Native?
Answer:
Hot Reloading instantly updates code changes in a running React Native application without restarting the app, helping developers improve speed, debugging, and productivity.
Benefits:
- Faster development
- Real-time updates
- Easy debugging
Q13. What are the advantages of React Native?
Answer:
React Native enables cross-platform app development using a single codebase, offering faster development, reusable components, near-native performance, lower costs, and strong community support.
Main advantages include:
- Cross-platform development
- Reusable components
- Faster development
- Near-native performance
- Large community support
