Top 20 React Native Interview Questions With Expert Answers

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The job market in the IT sector is highly competitive, especially when it comes to the field of React Native. With hundreds of individuals competing for the same position, knowing the right React Native interview questions and answers can make all the difference. Did you know that thousands of job seekers search for “React Native interview questions” every month? That’s how critical it is to be well-prepared. Whether you’re an experienced developer or a fresher, these questions can be your ticket to a promising career in mobile app development. In this article, we’ve compiled the top 20 React Native interview questions, explained in a simple way. So, let’s dive in and equip you with the knowledge you need to ace your next React Native job interview!

What Is React Native?

React Native is a framework for creating mobile apps using JavaScript and React. It allows developers to create cross-platform applications that work on both Android and iOS devices with a single codebase. 

Instead of writing different code for each platform, React Native employs a “write once, run anywhere” approach. It provides a set of pre-designed components and enables developers to create a native-like user interface. This makes app development faster and more cost-effective. 

React Native is popular for its efficiency, allowing developers to utilise their web development skills to build mobile apps, making it a top choice for many app creators.

Top 20 React Native Interview Questions

Knowing interview questions on React Native can boost your odds of selection. Here are the top 20 categorised interview questions for React Native to aid in your preparation.

React Native Basic Interview Questions

Here are some basic React Native questions and answers you must know about.

1. What are the fundamental differences between React Native and ReactJS?

With React Native, developers create mobile apps for iOS and Android, while ReactJS focuses on web applications within a web browser environment.

Although both take advantage of reusable JavaScript XML components, their syntax differs significantly. React Native employs app-view components like <View> and <Text>, whereas ReactJS relies on standard HTML tags such as <div> and <span>.

2. What are the core components of React Native?

Components are the fundamental elements in React Native that come together to form a complete mobile app. Among the essential components are:

• View: For displaying the app’s overall layout.
• Text: For rendering text.
• TextInput: For text input.
• ScrollView: To create a scrollable container.
• StyleSheet: For managing styles.
• Image: To display images.
• Button: For incorporating buttons.

3. What Is JSX In React Native?

JSX (JavaScript XML) is a syntax extension used in React Native to define the structure of user interfaces. It allows developers to write HTML-like code within JavaScript files. JSX makes it easier to create and visualise the UI components in your application.

4. What is the concept of state in React Native?

State in React Native is an object that represents the dynamic data of a component. It is used to store and manage data that can change over time and trigger re-rendering of the component when it’s updated. 

Components can have their own state, which is accessible using this.state. Consider this scenario: Suppose your app includes a form that prompts users to provide information. When a user starts typing in the form, the component’s state undergoes changes.

5. What is the purpose of props in React Native?

Props (short for properties) are a way to pass data from parent components to child components in React Native. They are read-only and allow you to customise and configure child components. Props help make components reusable and adaptable to different scenarios.

React Native Interview Questions for Freshers

Here are some React Native developer interview questions and answers for freshers:

1. What is a component in React Native?

A component in React Native is a reusable building block for user interfaces. It can be a button, input field, or more complex structures like navigation bars or screens. Components manage their state and can be combined to create complex UIs.

2. What are the threads used in React Native?

In React Native, a thread enables us to manage a single, sequential program flow. There are several threads in operation:

·     Shadow Thread: This thread operates in the background and is responsible for computing the layout generated using the React library within React Native.

·     MAIN/UI Thread: The main thread on which our app operates, handling user interface interactions and rendering.

·     JavaScript Thread: This thread is dedicated to executing the main JavaScript code, ensuring the functionality of the app.

3. Explain the difference between state and props in React Native.

State is used for managing data that can change within a component and is private to that component. Props, short for properties, are used to pass data from parent to child components and are read-only in the child component.

4. How can you optimise the performance of a React Native app, especially when dealing with large lists of data?

To optimise performance, you can use techniques like the FlatList component for efficient rendering of large lists, implement PureComponent for component rendering optimisation, and employ shouldComponentUpdate or memoisation to prevent unnecessary re-renders.

5. What tools and methods are available for debugging React Native applications?

React Native offers tools like React Native Debugger, Chrome DevTools, and the Developer Menu for debugging. You can also use console.log statements for logging and debugging purposes.

React Native Technical Interview Questions

Here are some React Native advanced interview questions with answers. The interviewer might ask these questions to gauge your technical skills.

1. What is the purpose of the Virtual DOM in React Native?

The Virtual DOM in React Native is an in-memory representation of the actual DOM. It helps optimise performance by reducing direct manipulation of the real DOM, allowing React to update only the elements of the UI that have changed, resulting in quicker rendering.

2. What are Native Modules in React Native?

Native Modules in React Native are JavaScript modules that allow you to call native code written in Java, Swift, or Objective-C. They enable React Native apps to access device-specific functionalities or third-party libraries that are not available out of the box.

3. How can you resolve common React Native performance issues?

When faced with performance challenges, developers have several remedies at their disposal. To address some prevalent performance issues, consider these solutions:

·     High CPU Usage: Improves app performance by compressing data, eliminating unnecessary renders, and implementing cache storage.

·     Memory Leaks: Prevent memory leaks by engaging in thorough debugging, refraining from excessive console statements, and routinely auditing code for inconsistencies.

·     Slow Navigation: To avoid navigation-related issues, opt for React Navigation over alternative tools like Navigator or NavigationExperimental. This choice can significantly enhance navigation speed and responsiveness.

4. How can Redux be implemented in React Native?

Implementing Redux in your React Native project involves the following steps:

· Install the required Redux packages from an online package registry.

· Create a dedicated Redux folder at the root of your application.

· Inside the Redux folder, introduce three essential files: actions.js, reducer.js, and store.js.

· In your newly created reducer.js file, import relevant components from ‘redux’.

· Within the store.js file, import necessary modules from ‘redux’ to set up the Redux store.

· Finally, ensure you import and connect the Redux store to your React Native application to enable state management.

5. What are the key differences between React Native and Flutter for mobile app development?

React Native uses JavaScript and allows code sharing between platforms, making it a good choice for mobile developers. Flutter uses Dart and offers a highly customisable UI but requires separate code for Android and iOS.

React Native Interview Questions for Experienced Professionals

Here are some React Native experience interview questions with answers.

1. How does React Native handle styling, and what are some of the best practices for managing styles?

React Native uses a JavaScript-based styling approach with a StyleSheet component for optimising performance. Best practices include using StyleSheet.create for style objects and avoiding inline styles for reusability and performance.

This is one of the most common React Native interview questions for 1 year experienced professional.

2. How do you handle navigation in a complex React Native app? Compare and contrast React Navigation and React Native Navigation.

Navigating the React Native apps can be managed using libraries like React Navigation (JavaScript-based) or React Native Navigation (native bridge-based). React Navigation is more flexible and cross-platform, while React Native Navigation offers native performance but requires separate code for Android and iOS.

This is one of the most common React Native interview questions for 2-year experienced professionals.

3. Explain the concept of native modules in React Native and provide an example of when you might need to create a custom native module.

Native modules in React Native allow communication between JavaScript code and native code (Java/Objective-C). You might create a custom native module when you need to access a specific hardware feature or integrate a third-party native library not covered by existing JavaScript modules.

This is one of the most common React Native interview questions for 3-year experienced professionals.

4. How can you implement deep linking in a React Native app, and what are the benefits of incorporating deep linking?

Deep linking allows users to navigate to a specific screen or content within an app via a URL. To implement it, you can use libraries like React Navigation’s Linking module. Benefits include improved user engagement and seamless content sharing.

This is one of the most common React Native interview questions for 5-year experienced professionals.

5. Explain the use of CodePush in React Native and when it might be advantageous for app deployment and updates.

CodePush is a Microsoft service that allows you to push app updates directly to user devices without going through the app store review process. It’s beneficial for delivering critical bug fixes and updates quickly and efficiently, reducing the app store release cycle.

Conclusion

Mastering these top 20 React Native interview questions and their expert answers can significantly boost your chances of success in your next job interview. 

React Native job offers exciting opportunities in the mobile app development space, and being well-prepared is key. So, if you are ready to take the next step in your React Native career, visit Hirist to explore the best job opportunities. 

Hirist is your platform for finding job opportunities in the IT sector, dedicated to connecting talented professionals, both experienced and freshers. Your next dream job could be just a click away!

FAQs

What are the coding questions asked in the React Native interview?

Here are some common React Native coding interview questions:

• Can you create a basic React Native component, like a button or input field, and illustrate its utilization within a React Native application?
• How would you set up Redux for state management in a React Native application?
• Can you outline the steps involved in integrating a RESTful API into a React Native app?

How can I prepare effectively for React Native MCQs?

To prepare for React Native MCQs, check React Native documentation, work on practical projects, and practice coding. Additionally, use online resources and take sample MCQ tests to assess your knowledge and improve your understanding of key concepts.

What are some common interview questions for professionals with 1 year of experience in React Native?

Here are some React Native interview questions for experienced individuals:

• How do you install and set up a React Native application? Can you outline the key steps?
• What steps can you take to avoid memory leaks in a React Native application?
• Explain the primary function of a ‘TouchableHighlight’ component in React Native.
• When faced with optimising a long list of items using FlatList, what strategies or techniques would you employ?
• How would you ensure that animations in a React Native app don’t block the JavaScript thread and maintain smooth performance?

What are some common interview questions for professionals with 2 years of experience in React Native?

Here are some React Native interview questions for experienced individuals:

• Describe the purpose and usage of the Render Props Pattern.
• Create a React application that displays the message “Hello World!”
• In the context of React Native, what does “Fabric” refer to?
• Can you define the role and importance of the InteractionManager in React Native?
• Enumerate the primary characteristics of “dumb components” in React.

What are some common interview questions for professionals with 3 years of experience in React Native?

Here are some React Native interview questions for experienced individuals:

• Can you outline the three fundamental principles of Fabric Architecture?
• What is the role of Smart/Container components in React development?
• Can you provide an overview of the process involved in the re-architecture of React Native?
• Explain the function and significance of the Gesture Responder System in React Native.

What are some common React Native interview questions for professionals with 5 years of experience?

Here are some React Native interview questions for experienced individuals:

• React Native employs which JavaScript engine for its operations?
• In the context of setting up a React Native development environment on MacOS, what is the purpose of installing Watchmen?
• What is the definition of Presentational/Dumb components in the context of React development?
• Distinguish between ShadowDOM and VirtualDOM, highlighting their key differences.