React vs. React Native: What are the differences?

As someone conversant with trending technologies and keen on learning about web and mobile application development, chances are you've heard of React and its mobile counterpart, React Native.

But what exactly sets them apart? This article compares React and React Native and outlines their core aspects, shared principles, and distinct features.

#React vs. React Native

In 2013, React emerged from Meta (formerly Facebook)’s need to build dynamic, high-performing web interfaces. React introduced building UIs through a component-based architecture. It also introduced a virtual DOM system-optimized rendering, making applications faster and more responsive.

With React's success in web development, Meta saw an opportunity to extend it to mobile app development. React Native was introduced in 2015 and leveraged the power of React, enabling developers to use a similar component-based UI approach for mobile platforms.

The goal was to allow for a single codebase that could run on iOS and Android, significantly reducing development time and costs compared to traditional native development for each platform.

At their core, React and React Native share the same design philosophy and many functionalities. However, their application domains and technical implementations differ significantly.

React is used to develop web applications that run in a browser environment and leverage HTML and CSS. React Native is used for mobile applications, translating React code into native mobile components by leveraging the native platform's APIs.

For example, the View component simplifies the creation of user interfaces in React Native, rather than writing separate code for each platform in Kotlin/Java for Android or Swift/Objective-C for iOS. At build time, React Native translates this component into native equivalents like UIView for iOS or android.view.View for Android.

#Things that carry over well from React to React Native

For developers familiar with core React concepts, architectural principles, and performance optimization techniques looking to learn React Native. It should be smooth. Let’s explore some aspects that carry over well.

Core React concepts

React's core concepts, such as the component lifecycle, composition, and the use of JSX, are consistent in React Native, making the knowledge transfer straightforward.

1. Component lifecycle

The lifecycle methods or hooks in React help manage the lifecycle of components, such as mounting, updating, and unmounting. These are also the same in React Native.

import React, { useEffect } from 'react';
    import { View, Text } from 'react-native';
    
    function App() {
      useEffect(() => {
        // ComponentDidMount
        console.log('Component mounted');
    
        return () => {
          // ComponentWillUnmount
          console.log('Component will unmount');
        };
      }, []);
    
      return <View><Text>Hello, world!</Text></View>;
    }

2. State management

State management in React and React Native works in the same way. You can use hooks like useState to manage local state within components.

import React, { useState } from 'react';
    import { View, Text, Button } from 'react-native';
    
    function Counter() {
      const [count, setCount] = useState(0);
    
      return (
        <View>
          <Text>You clicked {count} times</Text>
          <Button onPress={() => setCount(count + 1)} title="Click me" />
        </View>
      );
    }

3. JSX

JSX is a syntax extension for JavaScript that allows you to write HTML-like code in your JavaScript files. In both React and React Native, JSX describes the UI.

// Mobile application
    import { Text } from 'react-native';
    
    function App() {
      return <Text>Hello, world!</Text>;
    }

React architectural concepts

The architecture of a React application, including state management, data flow, and component structure, can be mirrored in React Native.

1. State management (Redux/Context API)

Whether using Redux for global state management or the Context API for more localized state sharing, the implementation remains the same across React and React Native.

For example, React and React Native can utilize the Context API in the same way to pass data through the component tree without having to pass props down manually at every level.

import React, { createContext, useContext, useState } from 'react';
    
    const CountContext = createContext();
    
    function CountProvider({ children }) {
      const [count, setCount] = useState(0);
      return (
        <CountContext.Provider value={{ count, setCount }}>
          {children}
        </CountContext.Provider>
      );
    }
    
    function useCount() {
      const context = useContext(CountContext);
      if (!context) {
        throw new Error('useCount must be used within a CountProvider');
      }
      return context;
    }

2. HTTP requests (Axios/Fetch API)

The way you make HTTP requests in React with Axios or Fetch API is the same in React Native.

useEffect(() => {
      fetch('https://api.example.com/data')
        .then(response => response.json())
        .then(data => console.log(data));
    }, []);

Performance optimization techniques

Many performance optimization techniques in React, such as memoization, lazy loading, and efficient state management, are also applicable in React Native.

1. Memoization (React.memo/React.useMemo)

These techniques prevent unnecessary re-renders by memoizing the component or values, thus improving performance.

const MyComponent = React.memo(function MyComponent(props) {
      /* render using props */
    });

2. Lazy loading (React.lazy)

This feature allows you to render a dynamic import as a regular component, reducing the bundle size and speeding up the initial load time.

const OtherComponent = React.lazy(() => import('./OtherComponent'));
    
    function MyComponent() {
      return (
        <React.Suspense fallback={<div>Loading...</div>}>
          <OtherComponent />
        </React.Suspense>
      );
    }

Other React tools

Many tools used in the development ecosystem provide SDKs compatible with React and React Native. This compatibility ensures developers can use the same tooling to monitor performance, track errors, and analyze user behavior across web and mobile platforms.

Tools like Sentry, New Relic, and LogRocket offer SDKs for React and React Native, allowing developers to monitor application performance and track issues in real time.

import * as Sentry from '@sentry/react-native';
    
    Sentry.init({
      dsn: 'YOUR_SENTRY_DSN'
    });
    
    function App() {
      throw new Error('Test Sentry Error');
      return <View><Text>Hello, world!</Text></View>;
    }

Tools like Bugsnag and Crashlytics can also be integrated into React and React Native to report errors, provide insights into application stability, and help improve user experience.

Google Analytics, Mixpanel, and Amplitude are examples of analytics tools that offer SDKs for both web and mobile platforms. These SDKs enable developers to gather insights into user interactions and app performance.

#Things that are different when developing for mobile with React Native

While the foundational React concepts remain consistent for React Native, the application in mobile environments necessitates adjustments in areas such as styling, library selection, device feature access, and more. Let’s explore some key differences:

1. Styling

CSS is extensively used in React to style components. React Native, however, uses a JavaScript-based styling system influenced by CSS but has its own properties and constraints.

In React, you can use CSS files or inline styles:

function WebComponent() {
        return (
            <div style={{ color: 'blue', margin: '10px' }}>
                Hello, this is a styled web component!
            </div>
        );
    }

In React Native, styles are not defined in CSS files but in JavaScript objects using the StyleSheet.create() method. This approach provides validation and optimization for the styles within the React Native environment.

import { View, Text, StyleSheet } from 'react-native';
    
    function NativeComponent() {
        return (
            <View style={styles.container}>
                <Text style={styles.text}>
                    Hello, this is a styled native component!
                </Text>
            </View>
        );
    }
    
    const styles = StyleSheet.create({
        container: {
            margin: 10,
        },
        text: {
            color: 'blue',
        },
    });

2. Library availability

The ecosystem of libraries in React and React Native can differ significantly due to the distinct nature of web and mobile platforms.

For instance, while axios or fetch can be used for HTTP requests in React and React Native, certain UI component libraries like Material-UI are designed specifically for web use. They cannot be used directly in React Native. Instead, React Native has its own set of UI libraries, such as React Native Paper, that are tailored for mobile development.

3. Mobile hardware vs. browsers

React Native provides direct access to mobile device features like the camera, GPS, accelerometer, etc., which are not as readily accessible or consistent across browsers in web development.

import { Camera } from 'expo-camera';
    
    async function accessCamera() {
        const { status } = await Camera.requestPermissionsAsync();
        if (status === 'granted') {
            console.log('Camera access granted');
        } else {
            console.log('Camera access denied');
        }
    }

In web development, accessing device hardware like the camera is usually more complex and requires dealing with varied browser permissions and APIs.

4. Navigation

Navigation in web apps typically relies on the browser's URL and history, managed by libraries like React Router. In contrast, mobile apps often use stack, tab, or drawer navigation, managed by libraries like React Navigation in React Native.

import { NavigationContainer } from '@react-navigation/native';
    import { createStackNavigator } from '@react-navigation/stack';
    
    const Stack = createStackNavigator();
    
    function NativeApp() {
        return (
            <NavigationContainer>
                <Stack.Navigator>
                    <Stack.Screen name="Home" component={HomeComponent} />
                </Stack.Navigator>
            </NavigationContainer>
        );
    }

5. Releases

The process of releasing applications is markedly different between web and mobile environments.

The release process for React web apps is straightforward: build the project and deploy the output to a server. This process can be automated with CI/CD pipelines.

In React Native, mobile apps are distributed through app stores (Apple App Store, Google Play Store), requiring compliance with platform-specific guidelines and a review process before release.

Updates to mobile apps must be pushed through these stores and are subject to approval, which can delay availability.

6. Development and dev experience

Developing in React and React Native offers distinct experiences, particularly due to the underlying platforms and tooling differences.

Developers can use live reloading and hot module replacement (HMR) with tools like Webpack, enabling real-time updates in the browser during development.

Debugging is often done directly in the browser using built-in developer tools.

React Native, however, includes a live reloading feature and a hot reloading mechanism, allowing developers to see the results of the latest changes immediately.

Debugging can be more complex, often requiring platform-specific tools like Xcode for iOS or Android Studio for Android, in addition to React Native's own debugging tools.

7. Testing

Testing strategies can vary significantly between web and mobile due to platform-specific elements.

Common testing frameworks include Jest for unit tests and React Testing Library for component tests. End-to-end testing can be done with tools like Cypress or Selenium.

import { render, screen } from '@testing-library/react';
    import App from './App';
    
    test('renders hello world', () => {
      render(<App />);
      expect(screen.getByText('Hello, World!')).toBeInTheDocument();
    });

Jest can also be used for unit testing in React Native. Detox or Appium are popular choices for UI and integration testing, providing a way to automate user interactions on real devices.

import React from 'react';
    import App from './App';
    import renderer from 'react-test-renderer';
    
    test('renders correctly', () => {
      const tree = renderer.create(<App />).toJSON();
      expect(tree).toMatchSnapshot();
    });

8. CI/CD

Continuous Integration and Continuous Deployment (CI/CD) practices are crucial in both environments but have different focuses and tools.

CI/CD for the web involves automated testing, build, and deployment processes using tools like Jenkins, GitHub Actions, or GitLab CI. The web app's assets are compiled, tested, and then deployed to a web server or a CDN.

For React Native, CI/CD includes additional steps like building app binaries, running mobile-specific tests, and submitting the app to the relevant app stores using tools like Fastlane.

Mobile CI/CD must handle multiple environments (iOS, Android) and may include beta distribution through TestFlight or Google Play Beta.

9. Performance Optimization

Optimizing performance requires different approaches and considerations for web and mobile.

For React, focus on reducing bundle size, optimizing assets, and improving network performance. Tools like Webpack can split code and lazily load parts of the application.

For mobile, performance optimization often revolves around reducing memory usage, optimizing native code interactions, and ensuring smooth animations. To diagnose and optimize performance, profiling tools specific to iOS or Android, as well as React Native's performance monitoring tools, are used.

#One CMS for both React and React Native

Managing content for web and mobile apps can be streamlined using a single content management system (CMS).

Hygraph, for instance, is a headless CMS that leverages GraphQL to efficiently serve content to React and React Native applications. It provides a flexible and efficient way to query exactly the data you need, reducing over-fetching and under-fetching issues commonly found in traditional REST APIs.

Hygraph offers easy integration and the ability to deliver content across different platforms, making it an ideal choice for developers working with React and React Native. Learn how to fetch content from Hygraph into your React Native application in three steps.

#Conclusion

While React and React Native share many principles and techniques, the specifics of mobile development bring unique challenges and considerations.

By understanding these differences and leveraging the shared strengths, developers can efficiently build robust, cross-platform applications that deliver exceptional user experiences.