React Native Multiple Choice Questions (MCQs) and Answers

Too many images in memory

Excessive event listeners

Rendering too many components at once

Large data arrays in state

To access device-specific functionality

To improve JavaScript performance

To replace state management

To handle navigation

Only Java

Java and Swift

Java, Kotlin, Objective-C, Swift

Only JavaScript

It connects JavaScript code to native modules

It speeds up rendering

It prevents memory leaks

It enables Redux

@ReactModule

@ReactNativeModule

@ReactMethod

@NativeModule

Extend RCTBridgeModule and use RCT_EXPORT_METHOD

Use NativeModule.create()

Extend ReactModuleBridge

Write a SwiftModule class

NativeModules.MyModule.myMethod()

NativeModules.callMethod('MyModule')

import { MyModule } from 'react-native'

useNativeBridge('MyModule')

The module was not linked properly

The module is only available on iOS

The JavaScript code is incorrect

React Native does not support native modules

The package is not registered in MainApplication.java

React Native does not support Android

The app requires Expo

The bridge is disabled

To test UI components

To handle API requests

To manage state

To optimize animations

Detox is used for end-to-end testing, while Jest is for unit testing

Detox is used only for Android apps

Jest cannot test UI components

Detox is faster than Jest

It can simulate real user interactions

It is built into React Native

It does not require a test runner

It can test JavaScript code directly

jest.mock('axios')

jest.apiMock('fetch')

mockAPI('axios')

jest.spyOnFetch()

expect(component).toMatchSnapshot()

testSnapshot(component)

expect(component).snapshotMatch()

jest.snapshot(component)

The test is not wrapped in act()

Jest is outdated

The app is not compiled

The component is missing prop validation

Emulator/simulator is not running

Jest is not installed

React Native does not support Detox

Detox does not work with functional components

AsyncStorage

Redux Store

SecureStore or Keychain

Local JSON file

API keys can be stolen if the app is decompiled

API keys are too large to store in the source code

API keys slow down performance

API keys require encryption before use

Obfuscating JavaScript code

Removing all third-party libraries

Blocking app updates

Using Redux for state management

AsyncStorage.setItem('token', value)

SecureStore.setItemAsync('token', value)

localStorage.setItem('token', value)

Redux.setToken('token', value)

Use https connections

Disable JavaScript debugging

Use SSL pinning

Disable API logging

Debugging slows down the app

Debugging exposes sensitive information

Debugging is not supported in production

Debugging breaks Redux state

Using eval() or setTimeout() with user input

Using Redux for state management

Using TypeScript instead of JavaScript

Using functional components

Faster development with a single codebase

Better performance than native apps

No need for testing

Automatic bug fixes

React Native is difficult to learn

React Native does not support animations

Native development provides better performance for complex applications

React Native does not support APIs

Limited third-party libraries

Difficulty in managing state across multiple screens

Incompatibility with iOS devices

Slow compilation

Using FlatList for optimized rendering

Storing all data in Redux

Keeping data in component state

Using useEffect for UI updates

Lazy load non-essential components

Use Redux for all state management

Increase JavaScript bundle size

Disable native modules

Excessive re-renders

Using useEffect too frequently

Unoptimized images

Large navigation stack

Using React Profiler

Manually checking state changes

Using Expo Debugger

Reducing state variables