When it comes to building cross-platform apps, React Native and Expo SDK offer a streamlined approach. The Expo SDK consists of npm packages that are versioned together, ensuring compatibility across iOS, Android, and web platforms. This integrated system simplifies the dependency management issues often faced in React Native development.
Expo Go, a reusable native runtime, allows developers to open their apps on iOS and Android instantly without native builds. This approach reduces complexity and speeds up the development process, making it as straightforward as web development.
Development Cycle and Fast Refresh
The development cycle with Expo and React Native is designed for efficiency. By running Expo Start, developers can see their app's bundler dev server URL in QR form, which can be scanned by a smartphone camera to open the app in Expo Go. This process resembles how a web browser interacts with a local dev server, enhancing the development experience.
React Native uses primitives like view, image, and text instead of traditional HTML elements. These primitives render to native views on each platform, maintaining a consistent appearance across devices. Fast refresh ensures that updates preserve the React component state, enabling quick iterations.
Publishing and Deployment with EAS
Deploying mobile apps has historically been complicated, but Expo Application Services (EAS) simplifies the process. EAS build automates native code signing and validation, minimizing the need for local resources. It allows iOS development on any device by handling builds in the cloud.
With EAS CLI, developers can submit their app to app stores with a single command, reducing the steps involved. This streamlining is akin to web development practices, enhancing accessibility for developers without macOS machines.
Over the Air Updates and App Store Restrictions
Expo's over-the-air updates allow instant updates to JavaScript and assets in the app. By using Expo Publish, updates are bundled and pushed to a hosting service, waiting for the user to open the app again. This approach mirrors web service worker caching policies.
While Expo enables rapid development, app store restrictions necessitate using the Apple App Store and Google Play Store for distribution. EAS build automates this process, ensuring compliance with platform requirements.
Custom Native Code and Development Clients
Although Expo provides extensive tools and APIs, there may be occasions when custom native code is necessary. Developers can create custom development clients, similar to Expo Go, with specific native features by using npm to install React Native modules and rebuilding the app.
Expo's auto-linking, config plugins, and Expo modules facilitate the integration of native code. These tools automate the linking and configuration processes, streamlining the development experience.
Managed Workflow vs. Bare Workflow
Expo offers two main workflows: Managed and Bare. The Managed Workflow reduces the need for direct interaction with native code, focusing on cross-platform configuration. The Bare Workflow provides full control over every project aspect, ideal for developers needing granular customization.
Managed Workflow projects utilize a config file, app.json, to manage iOS and Android folders. This setup simplifies upgrading by allowing developers to regenerate native projects based on the config file, similar to npm's package management system.
Streamlining React Native Development
Expo addresses common React Native challenges, such as native runtime creation, dependency management, and app deployment. By leveraging Expo Go, developers bypass the need for Xcode to display a basic app on a device. The Expo SDK ensures package compatibility, while one-command app deployment simplifies distribution.
Upgrading React Native applications is notoriously challenging. Expo's approach makes it comparable to upgrading any React project, reducing the complexity and frequency of native upgrades.
New Features and Future Developments
Expo continues to evolve, introducing support for monorepos and the Expo Modules system. These advancements allow developers to write native code in a Node module and link it directly to Managed Workflow projects, enhancing flexibility and scalability.
Expo Modules provide a simplified way to write native code, using Swift and Kotlin as first-class languages. This system offers a well-documented foundation for building fast, efficient modules, improving the overall development experience in React Native.
Conclusion
Expo and React Native present a robust framework for building cross-platform applications. With tools like Expo Go, EAS, and Expo Modules, developers can streamline their workflow, reduce complexity, and focus on delivering high-quality apps. By addressing common pain points in React Native development, Expo empowers developers to create innovative solutions efficiently.
App development is hard, React and Expo make it easy!
It's never been simpler to build and deploy powerful mobile apps with incredible features to both Android and iOS users all over the world.
We’ll discuss building and deploying mobile apps seamlessly from the cloud using EAS, creating powerful dev clients (like browsers but for mobile app development) for testing your app, pushing OTA updates instantly to users, and much more — no native experience required!
This talk has been presented at React Advanced 2021, check out the latest edition of this React Conference.
React Native is a framework that allows developers to build cross-platform mobile applications using React and JavaScript. It enables the same codebase to render on both iOS and Android platforms by using native views instead of web views.
The core differences are that React Native uses proper native views instead of drawing views to Skia like in Chrome. This allows for platform optimizations such as smooth scrolling, gestures, and complex animations. React Native also supports the use of multiple threads and custom native clients for extra functionality.
Some challenges include the need to create a native runtime to get started, managing dependencies which are harder than in web development, distributing the app via App Store or Google Play Store which involves complex code signing, and frequent and complex upgrades requiring familiarity with iOS and Android native development.
Expo simplifies React Native development by providing tools such as a reusable pre-built runtime, fast iteration speed, and integrated cloud services. It allows developers to create and run apps without native builds, manage dependencies easily, publish apps with a single command, and add native code or customize the client with minimal complexity.
Expo CLI is a modern Node.js Command Line Interface that helps developers interface with the bundler, start a development server, and perform various development tasks. Developers can install Expo CLI globally and create new projects with commands like 'expo init' and run them on iOS, Android, or web platforms using NPM scripts.
Expo Go allows developers to instantly open their app on iOS and Android without needing to make native builds. It includes most of the APIs needed for complex native apps built ahead of time, reducing the complexity and time required to launch a 'Hello World' app, making it as easy as web development.
Expo uses a tool called Expo Application Services (EAS) for deploying apps. EAS automates native code signing, validation, and submission to the App Store or Google Play Store. Developers can submit their app with a single command, simplifying the traditionally difficult and error-prone process of deploying mobile apps.
Over-the-air updates in Expo allow developers to update JavaScript and assets in their app instantly. By running 'expo publish,' the JS bundle is pushed to a hosting service, which the app's runtime checks for updates. The next time the user opens the app, the updated version is downloaded in the background and presented.
Expo has two main workflows: the Managed Workflow and the Bare Workflow. The Managed Workflow allows developers to avoid working directly with native code and maximizes cross-platform configuration. The Bare Workflow provides full control over every aspect of the project, requiring manual updates for native configurations.
The Expo SDK is a set of npm packages versioned together to ensure compatibility. It includes core primitives and community packages that support iOS, Android, and web platforms. The SDK simplifies dependency management and provides a reliable versioning system to solve common issues encountered in React Native development.
Today's Talk discussed building cross-platform apps with React Native and Expo, addressing challenges such as setting up the native runtime and managing dependencies. Expo provides a pre-built runtime, native APIs, fast iteration speed, and integrated cloud services. EAS build simplifies app deployment by handling native code signing and validation. Over-the-air updates allow instant updates to JS and assets. Custom native code can be added using auto-linking and config plugins, and Expo supports both Managed and Bare workflows.
Today we're talking about building cross-platform apps with React and Expo. React Native allows us to write code once and render to multiple platforms. It uses proper native views for improved performance and allows us to reuse code across platforms. However, there are some challenges, such as setting up the native runtime and managing dependencies. The app's runtime must also be distributed to app stores.
2. Introduction to Expo and React Native Development
In this part, we'll discuss the challenges of code signing and upgrading React Native applications. We'll also introduce Expo, a set of tools that solve these issues. Expo provides a pre-built runtime, native APIs, fast iteration speed, and integrated cloud services. We'll cover creating an app, the development cycle, publishing to the store, adding native code, and upgrading the app. To get started, install Expo CLI, create a new project, and use NPM scripts to start on iOS, Android, or web. React Native's development cycle is fast and enjoyable, and it uses primitives to render native views for each platform. Community packages provide additional features.
3. Expo SDK, Expo Go, EAS Build, and App Distribution
The Expo SDK is a set of npm packages that work together and solve dependency issues in React Native. Expo Go is a reusable native runtime that allows instant app opening without native builds. Expo Start provides a QR code for easy access to the app. The app manifest and JS bundle are fetched from the server, similar to web development. Distribution of production apps must go through the Apple App Store and Google Play Store. EAS build simplifies app deployment by handling native code signing and validation.
4. Building and Submitting iOS Apps with EAS Build
This section covers the process of building and submitting iOS apps using EAS build. It simplifies the configuration and submission steps, reducing them to a single command. The integration with React and Expo eliminates common build failures. Once the build is complete, you can download the binary file, submit the app for review, or use Test Flight. Another groundbreaking feature is over-the-air updates, allowing instant updates to JS and assets in the app.
5. App Updates and Native Code
When users update the app, the new version is downloaded in the background, while the initial bundle is immediately presented. The cached version v2 is shown on subsequent app openings. This caching policy is optimized for Offline First and quick TTI. Exynos Hosted Service can push JS bundles and static assets, but not native code. App Store restrictions require iOS apps to go through the App Store and Android code through Google Play Store, which EAS build automates.
6. Adding Custom Native Code and Building Locally
To add custom native code, you can npm install any React Native module into your project and rebuild the app. Native code is linked using auto-linking, config plugins, and Expo modules. These mechanisms are used when building the app with Expo CLI or EAS build. To build locally, you need Xcode for iOS and Android Studio for Android. Expo CLI provides commands like exporun.ios and exporun.android to streamline the process.
7. Building Development Clients and Expo Workflows
React native apps have a hard-coded URL that may not match the dev server in the cloud. To solve this, Expo created ExpoDevClient, a package that brings back UI tools for the dev client. Expo has two workflows: Managed Workflow and Bare Workflow. Managed Workflow avoids native code and maximizes cross-platform configuration. Bare Workflow provides full control but requires individual changes for each native project. Upgrading apps in Bare Workflow can be challenging due to the long line between React Native versions.
8. Upgrading React Native and Expo Managed Projects
In an Expo managed project, your iOS and Android folders are managed by Expo CLI and configured using the app.json file. Upgrading your React Native app is as easy as upgrading any React project. You can change JS code and regenerate everything. Custom Native code can be written in the iOS and Android folders. Xbort provides solutions for React Native issues, making it easier to deploy and upgrade your app.
9. Xbort SDK 43 and Expo Modules
Xbort SDK 43 now has initial support for monorepos, allowing you to write native code in a Node module and directly link it into your managed workflow project. Xbo modules simplify writing native code for React apps and provide first-class support for Swift and Kotlin. The architecture used in Expo Modules is very fast, resulting in significantly faster compilation times compared to community versions.
10. Public Release and Q&A
We are making this public to provide a solid foundation for building fast modules and reaching Expo SDK level of quality. Tamash wrote a blog post with more details. Reach out to me on Twitter or Expo for questions or comments. We also have a forum and Discord. Thanks for joining us, Evan! Before the Q&A, I wanted to mention Evan's amazing Legos. Now, let's answer some audience questions. Bare Expo is no longer the same as an ejected app. Managed sits on top of Bare, allowing flexibility. Expo modules are available for all React Native apps. Thanks for sharing, Evan!
This Talk discusses Rack Native at Microsoft and the efforts to improve code integration, developer experience, and leadership goals. The goal is to extend Rack Native to any app, utilize web code, and increase developer velocity. Implementing web APIs for React Native is being explored, as well as collaboration with Meta. The ultimate aim is to make web code into universal code and enable developers to write code once and have it work on all platforms.
Documentation is often your community's first point of contact with your project and their daily companion at work. So why is documentation the last thing that gets done, and how can we do it better? This talk shares how important documentation is for React and React Native and how you can invest in or contribute to making your favourite project's docs to build a thriving community
React Server Components (RSC) offer a more accessible approach within the React model, addressing challenges like big initial bundle size and unnecessary data over the network. RSC can benefit React Native development by adding a new server layer and enabling faster requests. They also allow for faster publishing of changes in mobile apps and can be integrated into federated super apps. However, implementing RSC in mobile apps requires careful consideration of offline-first apps, caching, and Apple's review process.
The Talk discusses the combination of React Native and Kotlin Multiplatform for cross-platform app development. Challenges with native modules in React Native are addressed, and the potential improvements of using Kotlin Multiplatform Mobile are explored. The integration of Kotlin Multiplatform with React Native streamlines native implementation and eliminates boilerplate code. Questions about architecture and compatibility, as well as the possibility of supporting React Native Web, are discussed. The React Native toolkit works with native animations and has potential for open-source development.
This Talk discusses building cross-platform component libraries for React and React Native, based on a successful project with a large government-owned news organization. It covers the requirements for React Native knowledge, building cross-platform components, platform-specific components, styling, and the tools used. The Talk also highlights the challenges of implementing responsive design in React Native.
This Talk is about the development of MDX, a combination of Markdown and JSX, by a freelance full stack JavaScript developer. MDX is a powerful technology that allows for the creation of interactive content within blog posts and supports React components. The speaker developed RnMDX, a proper and polished MDX library for React Native, which can be dropped into any React Native app. RnMDX provides solutions for common issues with Markdown content in React Native and allows for the rendering of MDX content into native views. Bringing MDX into native apps is now easier, and it can be used for various purposes, such as serving the app layout from a CMS or creating interactive online magazines or blogs.
Introducing FlashList: Let's build a performant React Native list all together
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In this workshop you’ll learn why we created FlashList at Shopify and how you can use it in your code today. We will show you how to take a list that is not performant in FlatList and make it performant using FlashList with minimum effort. We will use tools like Flipper, our own benchmarking code, and teach you how the FlashList API can cover more complex use cases and still keep a top-notch performance.You will know:- Quick presentation about what FlashList, why we built, etc.- Migrating from FlatList to FlashList- Teaching how to write a performant list- Utilizing the tools provided by FlashList library (mainly the useBenchmark hook)- Using the Flipper plugins (flame graph, our lists profiler, UI & JS FPS profiler, etc.)- Optimizing performance of FlashList by using more advanced props like `getType`- 5-6 sample tasks where we’ll uncover and fix issues together- Q&A with Shopify team
Compared to unit testing, end-to-end testing aims to interact with your application just like a real user. And as we all know it can be pretty challenging. Especially when we talk about Mobile applications. Tests rely on many conditions and are considered to be slow and flaky. On the other hand - end-to-end tests can give the greatest confidence that your app is working. And if done right - can become an amazing tool for boosting developer velocity. Detox is a gray-box end-to-end testing framework for mobile apps. Developed by Wix to solve the problem of slowness and flakiness and used by React Native itself as its E2E testing tool. Join me on this workshop to learn how to make your mobile end-to-end tests with Detox rock. Prerequisites- iOS/Android: MacOS Catalina or newer- Android only: Linux- Install before the workshop
- Intro - Cleo & our mission- What we want to build, how it fits into our product & purpose, run through designs- Getting started with environment set up & “hello world”- Intro to React Native Animation- Step 1: Spinning the wheel on a button press- Step 2: Dragging the wheel to give it velocity- Step 3: Adding friction to the wheel to slow it down- Step 4 (stretch): Adding haptics for an immersive feel
Deploying React Native apps manually on a local machine can be complex. The differences between Android and iOS require developers to use specific tools and processes for each platform, including hardware requirements for iOS. Manual deployments also make it difficult to manage signing credentials, environment configurations, track releases, and to collaborate as a team. Appflow is the cloud mobile DevOps platform built by Ionic. Using a service like Appflow to build React Native apps not only provides access to powerful computing resources, it can simplify the deployment process by providing a centralized environment for managing and distributing your app to multiple platforms. This can save time and resources, enable collaboration, as well as improve the overall reliability and scalability of an app. In this workshop, you’ll deploy a React Native application for delivery to Android and iOS test devices using Appflow. You’ll also learn the steps for publishing to Google Play and Apple App Stores. No previous experience with deploying native applications is required, and you’ll come away with a deeper understanding of the mobile deployment process and best practices for how to use a cloud mobile DevOps platform to ship quickly at scale.
So you’ve gotten Detox set up to test your React Native application. Good work! But you aren’t done yet: there are still a lot of questions you need to answer. How many tests do you write? When and where do you run them? How do you ensure there is test data available? What do you do about parts of your app that use mobile APIs that are difficult to automate? You could sink a lot of effort into these things—is the payoff worth it? In this three-hour workshop we’ll address these questions by discussing how to integrate Detox into your development workflow. You’ll walk away with the skills and information you need to make Detox testing a natural and productive part of day-to-day development. Table of contents: - Deciding what to test with Detox vs React Native Testing Library vs manual testing- Setting up a fake API layer for testing- Getting Detox running on CI on GitHub Actions for free- Deciding how much of your app to test with Detox: a sliding scale- Fitting Detox into you local development workflow Prerequisites - Familiarity with building applications with React Native- Basic experience with Detox- Machine setup: a working React Native CLI development environment including either Xcode or Android Studio
So, you have a killer web app you've built and want to take it from your web browser to the App Store. Sure, there are a lot of options here, but most will require you to maintain separate apps for each platform. You want your codebase to be as close as possible across Web, Android, and iOS. Thankfully, with Capacitor, you can take your existing web app and quickly create native iOS and Android apps for distribution on your favorite App Store! Contents: This workshop is aimed at beginner developers that have an existing web application, or are interested in mobile development. We will go over:- What is Capacitor- How does it compare to other cross-platform solutions- Using Capacitor to build a native application using your existing web code- Tidying up our application for distribution on mobile app stores with naming conventions, icons, splash screens and more
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