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React-native interview questions
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Last Updated: Jun 12, 2024

react-native interview questions

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Ashwin Goyal
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18 Jun, 2024 @ 01:30 PM


React-native is an open-source framework based on JavaScript, developed by Facebook. It allows developers to develop cross-platform mobile applications using both JavaScript and TypeScript. It supports developing applications on android and ios. Most companies like Facebook, Airbnb, and Instagram look for a developer with good react-native knowledge. 

So If you have got an interview call and are looking to brush up your knowledge on React native by reading a quick guide for answering React Native Interview Questions, we have got you covered. In this article, we will look at the most asked react-native interview questions and the answers for you. Let’s discuss the most asked react-native interview questions in this article.

Also See, Hooks in React JS

React-native interview questions

1)What is react-native?
React-native is an open-source framework based on JavaScript, developed by Facebook. It allows developers to develop cross-platform mobile applications using both JavaScript and TypeScript.

2)Why is react-native different from Reactjs?
React-native is used to develop mobile applications whereas Reactjs is used to develop web applications using HTML.There also other better features provided by reactJs like security, routing better than react-native. Both react-native and Reactjs used JSX.

3)What are the benefits of using react-native for building mobile applications?
React-native provides us with some benefits for developing mobile applications like

  • Better Support for Third-Party Plugins
  • Modular Architecture
  • Code reusability
  • Pre-Developed components
  • Cost-effective, etc.

4)What is JSX?
JSX stands for JavaScript XML. It is an XML/HTML template syntax used by React. It extends ECMAScript and allows us to include HTML into JavaScript code. It is faster than JavaScript and ensures the quick and easy creation of components and templates in React. 

5)What are hybrid apps?
Hybrid apps are similar to all the other applications we install on devices. But they are developed in a native container using the mobile webView object, which ensures that the app always displays web content when we use it.

6)Can I install a specific version of React-native?
We can install any specific version of react-native using the following command.

react-native init newproject --version X.XX.X

The above command installs a specific version of react-native. You need to replace the ‘X’ with your preferred version number here.

7)What are React hooks?
The react hooks allow the developers to use state and other features without using a class. They allow us to reuse the logic of components without changing the hierarchy much. 

8)What is Redux?
Redux is a JavaScript application’s state management tool. It helps us code consistent applications that can be run in different environments and are easy to test. It helps us determine the state changes.

9)Why do we use Flexbox in react native?
We use flexbox in react-native to support the UI view for different devices with different screen sizes, to ensure the UI looks good and achieves the desired layout. The main properties used are; flexDirection, justifyContent, and alignItems.

10)What is the difference between Reloading and Hot Reloading in React Native?
The live reloading reloads or refreshes the entire application when a file or a minor change is done. In contrast, the hot reloading technique only refreshes the modified part to maintain the application's state constantly.

11)Can we use typeScript in react-native?
React-native is a JavaScript-based framework used to develop mobile applications. But it supports typescript as well because typeScript is the advanced version of JavaSCript with better support and features.

12)What are pure components in React?
A component is called pure if it renders the same output or content for the same state and props. React provides it with the pureComponent base class.

13)Build a React app to print a single statement?

import React from "react";
import { Text, View } from "react-native";

const HelloWorldApp = () => {
return (
flex: 1,
justifyContent: "center",
alignItems: "center"
<Text>react-native interview questions</Text>
export default HelloWorldApp;

The above code imports the react, text, and the view from react and react-native libraries. It returns the text "react-native interview questions" from the HelloWorldApp function.

14) Can you write react-native code for Android and IOS in the same codebase?
Yes, we can write the code for Android and IOS in the same codebase because react handles all the native component translations.

15)How to re-render a flatList?
We can re-render the flat list using the extraData property on the component - flatList.

data={data }

16)What is the difference between state and props?

The States are mutableThe Props are immutable
The states are set and updated by objects.We pass properties from parent components.
The States can be modified.The props cannot be modified.

17)What is a state in react-native?
The react-native provides us with a built-in state object, which allows us to store the values that belong to components. Whenever the state object changes, the components are re-rendered.

18)What is the use of the ScrollView component?
The scroll view is a container that contains multiple components and hides the overflow with the scroll bar so we can scroll down to see excess content. We can use the scroll bar both vertically and horizontally.

19)List some ways you can optimize an application?
There are different ways to optimize an application. They are

  • Compress or convert the raw JSON data instead of storing it
  • Optimize native libraries and the number of state operations
  • Use key attributes on list items
  • Compress images and other graphic elements
  • Make reduced-sized APK files for CPU architectures.

20)Which CSS properties are not supported by react-native?
The properties that are not supported by react are

  • Only two values of CSS display property that are supported in React native.
  • aspectRatio is a non-CSS property supported by React Native, which gives aspect ratio to give a size to an element. 
  • The marginHorizontal property has the same effect as setting both marginLeft and marginRight.
  • The default value of the position in React native is relative instead of static. So absolute positioning is always just relative to the parent.

21)Why do you think react has performance issues?
The primary cause of performance issues in react-native is the fast performance of threads. This happens when we pass the components from one thread to another or multiple threads.

22)Why do we use react hooks?
We use react hooks to share the logic across multiple functional components.

23)How to improve the performance of the images?
We can increase the performance of the image and quality by following these three steps

  • Server-side compression
  • Third-party tools such as Cloudinary
  • Image caching 

25)What is AppRegistry in react-native?
The AppRegistry is an entry point of JavaScript, used to run all the apps on react. All the app components should be registered using the method AppResgistry.registerComponent().

26)How to upgrade react-native to the latest version on your system?
We can directly install the newer version by specifying the version number as shown before in this article. Or else we can run the following commands.

react-native upgrade
react-native init

26)How can we use firebase in react-native?
We can use firebase in react native by following the given steps

  • Create a project in firebase.
  • Install the firebase tools using npm - npm install -g firebase-tools
  • Take the credentials from project settings in firebase.
  • Add them to the environment file.

27) How to import components in react-native?
We can import components in react by using the import statement and path of the component, as shown below. 

Import { bodyComponent } from “./src/app/body/body.component”;

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Key Takeaways

We have discussed the most asked react-native interview questions in this article. We hope this blog helped you understand react-native interview questions and their answers well. Please check out Coding Ninjas for more unique courses and guided paths if you want to learn more. Also, try Coding Ninjas Studio for more exciting articles, interview experiences, and fantastic Data Structures and Algorithms problems. Please upvote our blog to help the other ninjas grow.

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