Introduction to React Native: Supercharge Your Mobile Development with Expo

High Level Introduction to React Native with Expo

About this introduction:

In the upcoming 8 minutes, you will:

• Differentiate between React and React Native
• Grasp the fundamental concepts of Expo and its significance in React Native development.
• Gain insight into Expo's popularity among more than 50% of React Native projects.
• Explore Expo's diverse selection of pre-made modules and what they have to offer to potentially accelerate your development output.
• Acquire a high-level overview of Expo's capabilities and it's potential to elevate your React Native apps.
• Understand the fundamental principles of Expo Application Services (EAS), a set of cloud services and tools that can enhance your development process.
• Learn how to bridge Kotlin and Swift features with Expo's eject functionality, unlocking the power of native code within your Expo project.

In the next eight minutes, get ready to delve into the world of React Native development with Expo. Throughout this introduction, you'll differentiate between React and React Native, grasp the significance of Expo in React Native development, explore Expo's popularity, and uncover the potential of Expo's pre-made modules to boost your development speed. This overview will also highlight how Expo can bridge features between iOS and Android, offering you a unified toolkit. By the end, you'll have a clear understanding of Expo's capabilities and how it can enhance your modern mobile applications. Let's set sail on a journey through React Native and Expo, charting a course to create outstanding cross-platform mobile experiences.

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What is React Native? 

‍Purpose:

React (also known as ReactJS or React.js) is a JavaScript library used for building user interfaces (UI) for web applications. It focuses on creating interactive and dynamic UI components that can be rendered in web browsers.

React Native on the other hand, is an extension of React that is used for building native mobile applications. It allows us to use React's component-based architecture to build UI elements that are translated into native components on iOS and Android platforms.

Rendering: 

While sharing certain similarities, React and React Native significantly differ in their underlying mechanisms. React components render within web browsers, utilizing the DOM (Document Object Model), while React Native components seamlessly translate into native UI elements on Android and iOS. This translation not only ensures impressive performance but also grants apps a truly native appearance – hence the name "React Native."

Components: 

In React, components are created using an HTML-like syntax called JSX (JavaScript XML and based on ES6), made for rendering within web browsers DOM.

In React Natives, components mirror the appearance of native user interface elements on mobile platforms, utilizing buttons, text inputs, and lists with a truly native essence. We wrap these components in views, which aligns with the specific layout and styling conventions of mobile interfaces as opposed to divs which we use traditionally in react.

Styling: 

In React, styling is commonly achieved through CSS, CSS-in-JS libraries, or alternative styling methods. On the React Native front, a similar styling approach to CSS is adopted, yet it employs a distinct set of properties and values curated for mobile development.

In our experience, we've found value in utilizing tools like NativeWind, which utilizes Tailwind CSS as a scripting language to establish a universal styling system for our Expo applications. Additionally, we incorporate React Native Paper for its built-in modules, further enhancing our development process and enriching our app's user interface.

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Native APIs:

React Native uses native APIs offered by iOS and Android platforms. This extension grants access to device-specific features, such as camera capabilities, GPS functionalities, and notifications, enhancing the overall user experience.

Code Reusability: 

Sharing of UI code between React and React Native projects remains limited. However React Natives architecture allows for efficient sharing of logic and component structures between iOS and Android platforms, streamlining the development process and promoting consistent functionality across different devices.

Development Environment:

In the React ecosystem, development revolves around web-oriented tools and encompasses testing within web browsers, ensuring optimal performance for web-based experiences. Transitioning to the React Native landscape introduces a distinct development environment. Here, developers engage with the React Native CLI, utilize emulators/simulators, and conduct thorough testing on actual mobile devices. Guaranteeing peak performance and compatibility on both iOS and Android platforms, resulting in a seamless user experience.

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Introduction to Expo

More than 50% of React Native projects choose Expo, highlighting its significant role in modern app development. With over 75 pre-made modules and a staggering 600,000 projects built, Expo has become a cornerstone of React Native innovation. As of August 2023, Expo stands at SDK 49, aligning seamlessly with React Native 0.72.3. Embark on your developmental odyssey with this high-level introduction to Expo—an intuitive launching pad for crafting exceptional cross-platform mobile experiences.

Comparing App Development Tools:

Expo's journey began in April 2017, and since then, it has undergone a significant evolution. Initially, Expo emerged with a toolkit that primarily aimed to simplify the development process for React Native applications. Its mission was to alleviate complexities by abstracting certain intricacies, offering a streamlined route to crafting cross-platform apps using a single codebase. While various tools like Flutter, Ionic, Xamarin, NativeScript, and Cordova aid in cross-platform app creation, React Native holds a prominent position due to its rich functionality, comprehensive packages, extensive resources, and a vast user community.

It's important to highlight that Flutter is also undergoing a remarkably transformative trajectory as well, emerging as a compelling option for non-technical users who aspire to fashion customized user interfaces without necessitating coding skills. This enhancement positions Flutter as a robust solution for streamlined prototyping. While an in-depth exploration of Flutter isn't within the scope of there, its noteworthy advancements deserve recognition.

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Expo's Pre-Made Modules API:

Expo boasts an array of acclaimed pre-made modules that cater to a diverse range of functionalities, nurturing a more efficient and enriched app development journey. The Expo Camera module equips developers with seamless integration of device cameras, facilitating image and video capture within applications. Geolocation becomes a breeze with the Geolocation module, empowering apps with accurate location tracking. The Notifications module taps into push notifications, enabling real-time communication and engagement with users. With the Contacts module, developers can seamlessly access device contact information, streamlining social interactions and content sharing. Expo's Asset module effortlessly handles asset management, optimizing media resources and enhancing app performance. These modules, among others, epitomize Expo's commitment to providing ready-to-use solutions, culminating in a dynamic toolkit that accelerates the development process and enriches the user experience.

• Expo Camera: This module facilitates seamless integration of device cameras into your app, allowing users to capture photos and videos effortlessly. It provides an intuitive API to access camera functionalities and supports features such as image quality adjustments, camera switching (front or back), camera zoom, auto-focus, white balance, and flash mode.
• Expo Location (Geolocation): With this module, you can harness accurate geolocation services to enable location-based features in your app. Whether you're building maps, navigation, or location-aware applications, Expo Location offers straightforward access to GPS data.
• Expo Notifications: Enhance user engagement by implementing push notifications through this module. You can send real-time updates and notifications to users' devices, keeping them informed and engaged with your app's latest developments. Additionally, you can seamlessly schedule, receive, and respond to notifications using this versatile tool.
• Expo Calendar: Integrate calendar functionality into your app, allowing users to create, view, and manage events.
• Expo AsyncStorage: Store key-value data on the user's device for persistent storage. This module is useful for caching data, storing user preferences, or maintaining app state across sessions. (Storage limited by platform & intended for small amount of data: ~6 MB) 

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Expo Capabilities: 

Expo stands as a versatile and empowering framework that encapsulates a multitude of capabilities to elevate the development of React Native applications. Its robust ecosystem offers a spectrum of tools, pre-built modules, and streamlined workflows, collectively geared toward simplifying the creation of cross-platform mobile experiences. With Expo, developers can seamlessly access native device functionalities, ranging from camera integration and geolocation services to push notifications and more. The framework's unified codebase ensures effortless deployment on both iOS and Android platforms, while its hot reloading and fast refresh mechanisms accelerate the iteration process. Expo's commitment extends beyond development, as it extends over-the-air update capabilities to effortlessly enhance deployed apps. Moreover, Expo Application Services (EAS) ushers in cloud-powered efficiency, delivering optimized builds and advanced caching, further propelling the prowess of Expo as an indispensable tool for modern app creation.

Add Custom Native Code with Eject:

Expo's eject feature allows you to access and utilize platform-specific code and functionalities in your React Native project. With eject, you can seamlessly integrate native code written in Swift (for iOS) or Kotlin (for Android) into your Expo project. This means you can tap into device-specific features, libraries, or APIs that might not be available through Expo's pre-made modules.

In the CLI: `expo eject`

Comparing this to direct Swift and Kotlin development, Expo offers a bridge between the convenience of React Native and the power of these native languages. While direct Swift and Kotlin development can provide ultimate control and performance optimization, Expo significantly streamlines the development process by providing a unified codebase for both platforms. This translates to efficient cross-platform deployment and accelerated iteration. Additionally, Expo allows developers to bridge React Native with Swift, unlocking the potential to leverage Swift's native functionalities, such as SiriKit, while maintaining the benefits of React Native's productivity. Furthermore, developers can even eject the iOS and Android folders in React Native to integrate platform-specific code where needed. Expanding the scope, Expo's flexibility facilitates the incorporation of Google Assistant API into React Native apps, enabling voice interactions and further enhancing user experiences. This synergy between Expo, Swift, Kotlin, and potential Google Assistant integration empowers developers with a versatile toolkit for creating feature-rich applications that excel in both performance and efficiency.

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EAS Cloud fundamentals

EAS, part of Expo's toolkit for universal React Native apps, streamlines development with features like native builds, OTA updates, and analytics. It simplifies building and deploying native iOS and Android apps through an intuitive interface, ideal for newcomers or those focused on business logic. EAS's over-the-air (OTA) support allows hassle-free updates without app store or play store reviews, even enabling selective updates for efficiency. It empowers developers to save time and effort, concentrating on app innovation rather than intricate processes.

• Efficiency and Direct Deployment: OTA updates allow developers to efficiently push updates directly to users' devices, eliminating the need for users to download a new version from the App Store or Google Play Store. This streamlined approach not only saves time but also provides a more seamless and immediate user experience.
• Faster Deployment and Review Bypass: OTA updates via EAS also expedite the deployment process by bypassing the App Store and Google Play Store review procedures. This enables quicker delivery of essential bug fixes, enhancements, and novel features directly to users.
• Selective and Optimized Updates: Leveraging OTA capabilities, developers can meticulously deploy specific updates, targeting only the necessary changes for implementation. This precision minimizes data usage and ensures swifter updates, enhancing both efficiency and user satisfaction.
• Enhanced Control and Rapid Issue Resolution: With EAS-powered OTA updates, developers gain heightened control over their app's evolution. Critical issues can be promptly addressed without being constrained by the App Store approval timeline, allowing for agile and responsive updates.
• Incorporating EAS into OTA: updates not only ensures a smoother user experience but also accelerates development, empowers developers with granular control, and fosters a more nimble and adaptive approach to app enhancement.

EAS Short Summary: 

OTA updates swiftly deploy changes to users, ideal for urgent updates and iterative improvements. Conversely, direct App Store uploads ensure formal review, wide distribution, and compliance with Apple's guidelines—an official channel for app distribution. The decision depends on app specifics and development priorities.

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Conclusion:

We've highlighted the dynamic synergy between React Native and Expo, hopefully compelling you to consider using Expo for your next modern app development project. Expo's pre-made modules streamline development, from camera integration to engaging notifications. The Expo Application Services (EAS) further enhances efficiency with cloud-powered tools, enabling rapid updates and control. Expo equips you with a unified toolkit, propelling your app forward and delivering an exceptional user experience. When deciding your development path, Expo stands as a strategic choice, igniting efficiency, speed, and elevated user engagement. Let Expo elevate your app to new heights.

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