React Native Interview Questions and Answers

By Admin
Last update: 17 Nov 2020, 62 Questions

Developed by Facebook, React Native is a hybrid mobile framework that creates native-style apps for Android & iOS. It works with a common language, which is JavaScript. On this platform, you would learn such interesting facts and the best React Native interview questions and get ahead of the competition. It is highly used because of its shorter development cycles, and quicker deployment time as compared to individual native languages like Java, Swift, Objective.

Quick Facts About React Native
When did React Native Initial release? 26th March 2015
What is the latest version of React Native? React Native 0.63 released on 6th July 2020
React Native is Created By Facebook
What language does React Native use? It is based on React js, which is written in JavaScript.

React Native Advantages

  • Highly useful for native app developers with benefitting features.
  • Superbly cost-effective and code reuse
  • No need for recompilation with changes and live reloading of codes.
  • Use of intelligent debugging tools for text editors.

It can locate specific JavaScript code and easily downloaded and compiled on the app launch. Earlier, it was developed only to support iOS but as with improved app performance, Facebook also launched it on Android. However, the information you need, you may get it through the React Native Interview Questions for experienced and Freshers as well.

Most Frequently Asked React Native Interview Questions

Here in this article, we will be listing frequently asked React Native Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

1. Can we combine Android or iOS code in react native?

Yes, we can combine Android or iOS code in react native. React Native helps to smoothly combines the components written in Java, Objective-C or Swift.

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2. What are the advantages of native apps over hybrid apps?
Here are some of the advantages of native apps over hybrid apps:
  • Native app development has fewer dependencies for bugs to occur.
  • In the native app, you are not relying on cross-platform tools.
  • The processing speed of the native app is faster than the hybrid app.
  • It provides great designs and user experience than a hybrid app.
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3. What is the difference between React and React Native?
React React Native
It is a JavaScript library, supporting front-end web and being run on a server, for web applications and building user interfaces. It is a framework that compiles to native app components, allowing you to build native mobile applications for different platforms.
React Js is a Javascript Library where you can develop and run faster web applications. React-Native is a framework where you can develop mobile applications.
React is for websites. React Native is for mobile applications.

The ReactJs is a JavaScript library to develop apps in HTML5 while using JavaScript as the developing language. Whereas, React Native is a JavaScript framework used to create native mobile applications while using JavaScript as the development language.

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4. How to install a specific version of React Native?

To install a specific version of React Native, use this following command:

$ react-native init newproject --version [email protected]

Note: In the above, replace VersionNumber with the version of React you want to install.

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5. How to use map function in React Native?

The map function is used to show a list of elements in an array. It can be used in React Native like the following example:



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

export default class mapFunction extends Component {
constructor(props) {
this.state = {
array: [
title: "example title 1",
subtitle: "example subtitle 1"
title: "example title 2",
subtitle: "example subtitle 2"
title: "example title 3",
subtitle: "example subtitle 3"

list = () => {
return this.state.array.map(element => {
return (
<View style={{ margin: 10 }}>

render() {
return <View>{this.list()}</View>;

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6. What is HOC in React Native?

Higher-Order-Component, shortly known as HOC is an advanced React Native technique to reuse the component logic. The function obtains a component and returns a new element.



function HOC(Comp) {
     return class NewComp extends Component {
         render() {

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7. How to use the camera in React Native?

To use the camera to React Native, follow these steps carefully:

  • On Android, camera permission must be asked:
    <uses-permission android:name="android.permission.CAMERA" />
  • Now, to enable video recording feature add the following code to the AndroidManifest.xml:
    <uses-permission android:name="android.permission.RECORD_AUDIO"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  • For iOS, you must update the Info.plist with a usage description for camera
    <key>NSCameraUsageDescription</key> <string>Your own description of the purpose</string>
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8. What are pure components in React Native?

A React component can be viewed as pure on the chance that it renders a similar output for a similar state and props. Class components that extend the React are PureComponent class that is treated as pure components.

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9. What is the use of the arrow function?

The use of Arrow functions in React Native is to help reduce your application's memory consumption. It is done by reducing the CPU time required to iterate the over loops to generate the components necessary for your lists.

Here’s an example of Arrow function in render:
class Foo extends Component {
   handleClick() {
   console.log('Click happened');
render() {
   return <button onClick={() => this.handleClick()}>Click Me</button>;

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10. What is the difference between ShadowDOM and VirtualDOM?
ShadowDOM VirtualDOM
Shadow DOM creates small pieces of the DOM object which has its own, isolated scope as they represent. Virtual DOM creates a copy of the whole DOM object
It is a tool that is used in building the apps and websites that are based on components. It is a concept of DOM which is being used by Vue.js and React.js
It comes in small pieces and doesn’t represent the whole Document Object Model. It's done to improve the performance of the UI libraries
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11. How to navigate from one page to another in react native?

Navigation is done in react native by this.props.navigation.navigate('Page Name on which you want to navigate where')



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

class HomePage extends React.Component{
         return (
                 <text>Home Page</text>
                 <button onpress="{()=" title="Go to Detail page">this.props.navigation.navigate('Details')} ></button>


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12. What are the advantages of React Native?
Few significant advantages of React native are as following:
  • Conveniently uses the client as well as server side
  • Superbly cost effective and code reuse
  • Better code readability because of JSX use
  • Easy to integrate with other significant frameworks
  • Easy to write UI test cases because of React
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13. How to import components in React Native?
  • Add this code in the component.js file destination file
    import Title from './src/components/importcomponentdemo';
  • Here’s the complete code:
    import React from 'react';
    import { AppRegistry } from 'react-native';
    import App from './src/components/importcomponentdemo';
    const App = () => (
       <Title />
    AppRegistry.registerComponent('ComponentDemo', () => App);
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14. What is the point of StyleSheet.create in react native?

The stylesheet is a React native module that allows developers to create immutable stylesheet references. App developers can pass natural style object into the create() method, which will freeze the objects and assign each with an ID. It will allow developers to avoid creating a new style object every render pass and only once send the purpose across the asynchronous bridge.

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15. What is the use of Redux in React Native?

Redux is a standalone state management library present in React Native and can be used combined with any framework or library. With the use of Redux, app developers can use one application state as a global state and interact with the state from any react component will be easy.

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16. How to call web service in React Native?

Here’s an example to call a web service to React Native.

fetch('http://**someurl**', {
method: 'POST',
headers: {
   'Accept': 'application/json',
   'Content-Type': 'application/json',
body: JSON.stringify({
   username : "admin1",
   password: "admin13",

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17. How to install react native?

To install React Native, we will have to follow these steps:

  • Start with installing node and watchman
  • Then, install React native CLI with npm
  • Install Xcode and its Command line tools
  • Create a React Native project by using the following command

react-native init MyNewProject

cd MyNewProject

react-native run-ios

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18. How to handle multiple platforms in React native?

React Native easily handles multiple platforms. As the majority of React Native APIs are cross-platform, app developers have to write one React Native component, and it will work on both iOS and Android seamlessly. Facebook, the creator of React native, claims that the Ad Manager application has 87% code reuse across these two platforms. React Native also allows users to specify platform-specific versions of each component which they can then integrate into rest of the React Native application.

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19. What do you mean by interactionManager and why is it important?

The interaction Manager works on a long-running schedule after any interactions/animations have been completed. In particular, to run smoothly this allows Javascript animations.

It is important because it creates an interaction 'handle' on animation start, and clearing it upon completion in applications to register animations.

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20. How to create stack of screens in react native?

import React from 'react';
import { View, Text } from 'react-native';
import { createAppContainer } from 'react-navigation';
import { createStackNavigator } from 'react-navigation-stack';
class HomePage extends React.Component {
render() {
    return (
         <text>Home Page</text></view>
class DetailPage extends React.Component{
        return (
              <text>Detail Page</text></view>

const AppNavigator = createStackNavigator({
   Home: HomePage,
   Details: DetailPage,
    initialRouteName: 'Home',
export default createAppContainer(AppNavigator);

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React Native Interview Questions Related Videos

21. What does StyleSheet.create do?What are refs in React Native?

The Stylesheet.create function in React Native is used for the following:

  • It validates the keys and registers them to React
  • It creates a StyleSheet style reference from the specified object.
  • It allows you to send the style only once through the bridge while referring to all subsequent users through ID.

Short form for “reference”, Refs are used to access underlying DOM nodes or React elements within a React component.

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22. What is the difference between state and props?
State Props
States are mutual Props are immutable
The state is set and updated by the object. In props, you can pass properties from parent components.
The state can be modified Props can’t be modified.
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23. What is JSX?

JSX stands for JavaScript XML

It allows us to write HTML elements in React and place them in the DOM without any createElement() and/orappendChild() methods.JSX also converts HTML tags into react elements and makes it easier to write.



const myelement = <h1>React Interview Questions</h1>;
ReactDOM.render(myelement, document).

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24. What is AppRegistry react native?

It is an entry point of JavaScript which is used to run all the apps to React Native. All the components of the App root must register themselves with AppRegistry.registerComponent(), after that the native system will be able to load the bundle regarding the app. After that, they can run the app simply by invoking AppRegistry.runApplication().

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25. What type of data does a ListView take in react native?

To create a ListView in native we create DataSource type of data because React Native ListView is a view component that contains the list of items and displays in a vertically scrollable list.

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26. How to update react native with latest version?

It is important to upgrade the existing react-native to the latest version in order to access more featural aspects that involve views, APIs, classes, arrow functions, template string, import and export modules, array destructing and development tools.

Following steps should need to be performed to update the react-native to the latest version:

  • Update react native, react and Expo package versions for upgrading the expo projects in package.json
  • Install the latest SDK version which is compatible with the latest version of react-native in the app.json file.
  • Upgrade React Native CLI using the command: react-native upgrade
  • Install upgrade helper web tool for upgrading the applications
  • Upgrade existing file using the command react-native init
  • Perform troubleshoot activity to upgrade with react native CLI
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27. What are the new features in React Native 0.61?

React Native 0.61 is the latest version of react native which is proficiently able to optimize the features of react-native version 0.60. the latest version of react-native comes with the latest and improved features.

The react native version 0.61 is incorporated with four advanced level features such as:

  • React native 0.61 is provided with improved CocoaPods Support
  • For dimension updates, new useWindowDimensions Hook feature is provided
  • Fest processing and refreshing of the application
  • React native is upgraded to 16.9 as it opposes old names for unsafe methods
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28. What is API in react native?

API is the acronym for Application Programming Interface, which is a software intermediary that lets in two applications to talk to every other. Each time you use an app like Facebook, send an on the spot message or take a look at the weather on your phone, you’re the usage of an API.

In React Native, we can use the Fetch to swimsuit our needs. You can absolutely name the URL thru Fetch, and make requests to the server as needed.

Lifecycle approach in React Native

There are several lifecycle methods to React Native. We’ll use three of these lifecycle strategies in this article; constructor, componentDidMount and Render.

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29. How to use Axios in react native?

With the help of Axios, the user can send GET, POST, PUT, and DELETE requests to the REST API and render a response to the application. With the help of Axios, users can interact with the REST API. In general, Axios is a promise-based HTTP client which used by the react-native.

Axios is associated with a number of features which are enlisted below:

  • It makes XMLHttpRequests from the browser
  • From react native framework, it makes Http requests
  • It supports react-native API’s
  • It provides a client-side feature that protects the application from XSRF.
  • It automatically transforms response and request data.
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30. What are controlled and uncontrolled components in react native?
Controlled Components Uncontrolled Components
A controlled component is one that is bound to a value, and the changes inside it will be handled in code by using event-based callbacks. This is similar to the traditional HTML form inputs, but, here, the form data is handled by the DOM itself.
It does not maintain its internal state. It maintains its internal states.
Data is controlled by the parent component. Here, the data is controlled by the DOM itself.
It accepts the current value as a prop. A ref is used for their current values.
Has much efficient control over the form elements and data. Has less control over the form elements and the data.
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31. How to use firebase in react native?

Firebase is a mobile platform that helps you quickly develop high-quality apps, grow your user base and earn more money. This is a tool and infrastructure that users need to build better apps and grow a successful business. In addition, firebase is made up of a complementary feature that users can mix-and-match to fit your needs. There are total give key features of firebase namely authentication, Realtime database, cloud messaging, crash reporting and analytics.

Getting started with firebase by using following steps-

  • Create a firebase project in the Firebase console
  • Retrieve apikey, authDomian, DatabaseURL and storage bucket from firebase console
  • Create a new react-native project
  • Install firebase from npm
  • Add it into the react-native project
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33. How to use typescript in react native?

When a developer is working on a project and wants to maintain the project for a long period of time then the user should need TypeScript. In order to use the TypeScript user should need to configure the TypeScript because it gives an option to configure the compiler. Moreover, users can configure the TypeScript as per their requirements and can effectively prioritize the type of errors. Given below are the steps that will enable the developer to use TypeScript in react native-

  • Creating a project in react native using-
    react-native init myapp --template typescript && node myapp/setup.js && cd myapp
  • Set up and configure TSlint
    npm install --save-dev tslint tslint-eslint-rules tslint-react tslint-config-prettier
  • Setting up Jest
    npm install --save-dev ts-jest
  • Setting up an enzyme
    npm install --save-dev enzyme enzyme-adapter-react-16 react-dom @types/enzyme @types/enzyme-adapter-react-16
  • Setting up a test library of react-native
    npm install --save-dev react-native-testing-library
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34. List the most common commands used in React Native?

Here you will discover a list of fundamental instructions to start creating iOS and Android apps the use of React Native.

  • react-native init PROJECTNAME
  • react-native run-android
  • react-native run-ios
  • watchman watch-del-all
  • react-native link LIBRARYNAME
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35. Why react native is better than native?

React Native is better than native because of React native as it is a faster framework and allows the developers to create mobile applications that further support iOS and Android. The react native increases the speed of mobile development effectively and it is quite easier for the developers to maintain the mobile applications which are developed to react-native. It is easier for the developer to identify the bug in the applications which are developed in react native.

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36. Can we use react native for web?

Yes, we can use react native for the web as it makes possible to run react-native APIs and component on the web platform.

For example-

Web interfaces with high quality: It is easier to create web applications and user interfaces in JavaScript. It provides native quality of interactions and it supports multiple input modes also.

Write once, render anywhere: It interoperates with a number of React- Native DOM components. Moreover, it is compatible with all of the React Native API.

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37. What is Gesture Responder System in React Native?

Gesture Responder System is a system that manages the lifecycle of the applications which are built in React- Native framework. The applications automatically determine the intention of the users through touch. For example, the application determines slide on the widget, touch is scrolling or tapping. The Gesture Responder System allows the components to negotiate these touch interactions without integrating any sought of knowledge regarding their parent component and child component. React Native gesture responder system is the most powerful system, as it uses standard library to detect gestures such as scroll distance, single tap, double-tap, single tap confirmed and pinch distance.

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38. How to store data in AsyncStorage in react native?

When developers develop applications, they need to store information permanently for an application. The react native applications use the database to remember all the information which is related to the applications and their respective users. React Native uses AsyncStorage for data storing purpose. AsyncStorage is a simple, unencrypted synchronous, persistent, key-value storage system that is global to the application. On iOS, AsyncStorage is backed by native code that stores small values in the serialized dictionary and large values in separate files. On Android, AsyncStorage will use either RocksDB or SQLite based on which is available.

Four steps are needed to understand how to use AsyncStorage to React Native-
  • Don’t need to install any extra library. By default, it comes with React Native. Import {AsyncStorage} from 'react-native';
  • AsyncStorage uses key-value pairs for saving the data for example- AsyncStorage.setItem ('myKey', myValue);
  • To load the saved data run given the command- AsyncStorage.getItem('myKey'). then((myValue)=> {this.setState ({'myKey': myValue});});
  • Since loading data is a time-consuming task, it is designed to be an asynchronous operation. So getItem returned the promise, which will invoke the call back function when the read operation is completed.
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39. How to create a SQLite database in react native?
Given steps are used to create SQLite database in react native-
  • create a folder which is called as “www’ through the finder in the project folder
  • create a database file
  • add the created file to the project
  • Choose a file to add
  • Verify the structure of the project
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40. How to load data from server in React Native?

React Native gives the Fetch API which offers networking needs. React Native makes use of componentDidMount lifecycle method to load the records from server.

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41. How do you use props in react native?

Many of the components were customized post their development, by considering multiple parameters. These exclusive parameters are called Props.

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42. How do you pass props from one screen to another in react native?

When we creating an app containing multiple screens, then sometimes it is required to pass value between one screen to another one. This can be achieved by using this.props.navigation.navigate() function and this function is used to navigate between the different screens.

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43. What are states in React Native?

State in React Native is used within components to keep track of information and the most common way to set state in React Native is by using React's setState() method.

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44. When would you use a class component over a functional component?

A class component can be used over functional components when implementing the State and Logic. In the case of using the React lifecycle methods, the class component is recommended.

Under the class components, props can be passed easily with this.props

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48. What is fabric in react native?

Fabric is the latest architecture of React Native which has been proposed by the company to develop the close and better user experience of mobile apps than the native apps.

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49. What are the difference between a component and an element in React.

React Component: A class or function which optionally accepts inputs and returns a React element via JSX.

React Element: It describes what the user wants to be displayed on the screen, Simplifying it, the react element is an object representation for some UI.

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50. Is it possible to use the same code base for both Android and iOS in React Native?

Yes, it’s entirely possible. App developers use the same code base for iOS and Android as Reacts entirely takes care of the native components translations part. For example, a React Native ScrollView uses ScrollView on Android and native UiScrollView on IOS.

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51. What is react native and why it is used?

React Native is a next-generation JavaScript code library developed by Facebook for native app creation. The feature of reusable code across the web and mobile devices makes React Native highly demanding among developers. With the reusable codes, app developers don’t have to build the same app for different platforms from scratch.

This also helps businesses especially startups and medium enterprises to better sustain their workforce as now they can hire fewer individuals to perform the same task but in different operating systems.

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52. Explain the limitations of React native?
The React Native has following limitations or cons
  • Security risks
  • Single threaded interface
  • Poor memory management
  • Doesn’t support all native APIs
  • Dependable on third-party libraries
  • Not equivalent to true native apps written entirely on Java or Swift/Obj-C.
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53. Who is using react native?

Today hundreds and thousands of mobile applications are using React native as their base. Many multi-billion companies are also using this framework for their business apps, such as Facebook, Uber, Instagram, Wal-Mart, Skype, Pinterest, Tencent QQ, wix.com, delivery.com, Adidas GLITCH, JD, Baidu Mobile and more.

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54. Is React Native a Mobile App?

Yes, React Native complies with ALL the requires of a native mobile app using native app components. It's neither a mobile web app nor a hybrid mobile app that uses WebView to run the HTML5 app successfully. It builds a real mobile app, utterly indistinguishable from apps built using Java or Objective-C.

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55. How to run react native app on Android?
To run React Native in Android, we have to follow these:
  • First, enable the USB Debugging option inside the Developer Options.
  • Plug the device via USB to the development machine.
  • Run adb devices command to check that the device is correctly connected to ADB
  • Now install and launch your app by using the below-given command.

$ react-native run-android

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56. Write a program to display "Hello World" in react native?

Create a simple "Hello World" app by using modifying App.js file of FirstApp. Save the utility and reload by way of in reality pressing twice "R" or Ctrl+M (Reload).



import React, {Component} from 'react';  

import {Platform, StyleSheet, Text, View} from 'react-native';  

type Props = {};  

export default class App extends Component<Props> {  

render() {  

return (  


        <Text>Hello World</Text>  





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57. What do you mean by Dispatch in react native?

Dispatch is a feature of the Redux store. You call store.dispatch to dispatch an action. This is the only way to set off a kingdom change. With React Redux, your factors never get admission to the keep without delay - connect does it for you.

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58. How Virtual Dom works in React Native?

Virtual DOM is a copy of the real DOM. This node tree lists the elements, their attributions, contents, and properties also. Whenever any underlying data changes in React Native, the entire UI will be re-rendered in Virtual DOM representation. Then, the difference between previous DOM representation and virtual DOM will be counted. After that, the real DOM will be updated.

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59. How to call the function from another component in React Native?

Here’s an example to call a function from another component in React Native:

Create a function, sayHello and then use it as a named-function

const hellos = ['Hola', 'Salut', 'Ciao', 'Ahoj', 'Annyeong-haseyo', 'Aloha', 'Howdy', 'Ni Hao', 'Konnichiwa'];
const sayHello = function() {
return hellos[Math.floor((Math.random()*hellos.length))];

export { sayHello };

Now, you can import into whichever component you wish to share the functionality like this:

import { sayHello } from './hello';
class CompA extends React.Component {
    render() {
       return <span>{sayHello()}</span>;
class CompB extends React.Component {
    render() {
       return <span>{sayHello()}</span>;

<CompA />
<CompB />
</span>, document.querySelector('#app'));

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60. How do you add react navigation to react native?

You can install react navigation by the following command:

yarn add react-navigation
or npm install react-navigation

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61. What are the other modules need for react native navigation?
You have to install following modules in addition to react-navigation:
  • react-native-gesture-handler
  • react-native-reanimated
  • react-native-screens
  • react-native-safe-area-context
  • react-navigation-stack
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62. How to create stackNavigator in react native?

const AppNavigator = createStackNavigator({
      Home: {
          screen: HomeScreen,

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