July 2024 Summaries

Continuous Native Generation (CNG) is a process designed to streamline the maintenance and upgrade complexities of native projects in mobile app development, particularly for cross-platform frameworks like React Native. By generating native projects on-demand from concise input configurations rather than storing entire projects in source control, CNG simplifies the update process and reduces the burden of maintaining boilerplate code. This approach allows developers to focus on defining unique project aspects in a straightforward format, minimizing manual file adjustments and enhancing efficiency. With CNG, developers can more easily adopt platform upgrades, integrate complex native features, and manage custom native code, ultimately shifting focus toward feature development rather than maintenance. The process is facilitated by Expo Prebuild, which uses app configurations and package files to regenerate native projects, supporting seamless integration of updates and customizations. This method enhances the speed, consistency, and quality of mobile app development, helping teams better manage the evolving requirements of Android and iOS platforms.

Steve Galili, a Lead Software Engineer at MyWheels in Amsterdam, outlines the significant benefits of transitioning from React Native RNC CLI to Expo for their car-sharing platform, emphasizing the enhanced efficiency, collaboration, and development agility achieved. MyWheels, a leader in sustainable urban mobility in the Netherlands, faced challenges with slower builds and complex setups under RNC CLI, which hindered team collaboration and development velocity. The shift to Expo brought streamlined workflows, robust cross-platform capabilities, and simplified CI/CD processes through Expo App Services (EAS), allowing the team to expedite release cycles and onboard developers more smoothly. This migration not only improved the codebase and teamwork but also enabled web developers to seamlessly contribute to mobile development without needing deep knowledge of platform-specific intricacies. Expo's comprehensive documentation, community support, and built-in tools have become integral to MyWheels' development ethos, empowering them to deliver updates rapidly and focus on building the best car-sharing app in Europe.

Marcelo Terreiro Prado, a Senior Software Engineer at Brex, developed Flash Calendar, a performant and customizable calendar library for React Native, after encountering limitations with existing date picker libraries. Built for speed and flexibility, Flash Calendar features dark mode, localization, and Expo compatibility, and uses Shopify's FlashList for enhanced scrolling performance while minimizing unnecessary re-renders. Designed initially for Prado's personal finance app, Moni, Flash Calendar was created to address concerns about performance, bloat, and aesthetics. The library prioritizes minimal dependencies, employing a single 200-byte event-emitter, and is supported by extensive unit testing inspired by date-fns to handle complex date functions. Flash Calendar was developed using tools like Bun, Turborepo, and Storybook to ensure a seamless developer experience and is already utilized by various applications. As an open-source project, it emphasizes strong documentation, consumer feedback, and efficient project management, with future plans to expand its features based on user contributions and requests.

React Native applications are composed of native code and a JavaScript (JS) bundle, with the latter being capable of over-the-air updates, unlike the native part that requires app store updates. This capability is particularly beneficial in speeding up development workflows, as traditionally seen with tools like EAS Update and Microsoft CodePush, which bypass the app store review process to deliver updates directly to users. Expo is enhancing this process by integrating EAS Update with GitHub, allowing developers to receive updates automatically for each commit, thereby combining mobile and web development efficiencies. This integration supports two key workflows: previewing changes from pull requests through QR code scanning and pushing updates directly to users by committing changes to specific branches. This feature aims to streamline code review and deployment patterns, with further enhancements anticipated as part of Expo's ongoing expansion of EAS capabilities.

In 2010, an app called "Set Dances" was launched for iOS, designed to aid Irish step dancers in selecting tunes and adjusting playback speed during competitions. Despite no functional updates since 2013, the app faced removal from the App Store due to its age and low download numbers, prompting a rebuild using Expo SDK and EAS tools. The developer aimed to preserve the app’s original features, introduce Android and TV support, and simplify code by utilizing React Native and Expo packages. The redevelopment was notably faster and more efficient, leveraging modern tools like expo-av for audio playback and expo-router for navigation, highlighting how previously complex tasks became straightforward. The app’s new version, incorporating a refined UI and additional functionalities like Airplay and OTA updates, was approved quickly by iOS and Apple TV App Stores. The developer plans to release an Android version soon, reflecting on the positive experience of modernization and encouraging others to update legacy apps.