React Native: the past, the present and the future

As we approach React Native's 4th birthday, we've observed more progression towards our original vision than ever before. Even still, we have yet to realise its core mission of being as powerful as pure native. There have been many challenges that we've faced head on as they've surfaced. In overcoming them with the support of the community, we've managed to establish React Native as a force that is now defining the future of the segment.

In this talk, we'll explore this history-in-the-making before diving deeper into more technical subjects including Fabric, the JSI, and TurboModules. With all the pieces of the puzzle in place and landing on master in upcoming months, we are closer to reaching our original objective than ever before while pushing the limits to a whole new level.

Transcript

1. REACT NATIVE: the past, the present & the future
2. I am... Lorenzo Sciandra @kelset • I use Twitter, A LOT • React Native Developer ~3yrs ◦ Physio ◦ Day8 (The Yacht Week) ◦ Drivetribe • React Native Core >1yr ◦ Maintainer ◦ Releases ◦ React Native Community org
3. THE PAST
4. A long, long time ago • In 2013, Facebook engineers were facing classic mobile app issues: ◦ Disjointed, proprietary technology stacks ◦ Slow to iterate ANDROID IOS REACT • On the other end, React on web ◦ Fast to iterate
5. A long, long time ago • In 2015, React Native was introduced: ◦ Uses React & Javascript to give full access to native views via a bridge ◦ “write once, run anywhere.” —> "learn once, write anywhere” NATIVE(s) ~ REACT BRIDGE
6. THE PRESENT
7. Something clicked • A lot of companies... • ...on a lot of platforms https://github.com/pavjacko/react-native-vanilla
8. Something clicked • The Open Source community has grown incredibly: • Tons of libraries: ◦ react-native-elements ◦ react-navigation ◦ react-native-screens ◦ react-native-gesture-handler ◦ react-native-reanimated ◦ ...
9. The boundaries of React Native ~ REACT BRIDGE JAVASCRIPT NATIVE(s) JSC SHADOW TREE JSON (ASYNC) NATIVE MODULES
10. The boundaries of React Native BRIDGE SHADOW TREE JSON (ASYNC) NATIVE MODULES "React Native was designed to return a single JSON message that lists mutations to perform" • The messages are asynchronous and batched: ◦ Some native APIs want SYNC ◦ Can’t directly call native functions • The native modules are: ◦ Eagerly initialized ◦ always singleton
11. THE FUTURE
12. The approach of the re-architecture ~ REACT BRIDGE JAVASCRIPT NATIVE(s) JSC SHADOW TREE JSON (ASYNC) NATIVE MODULES “How can we improve it*?” * In a way that is backward-compatible
13. Re-architecture: step 1 • Leverage on the improvements from the React team ◦ Concurrent React ◦ Suspense ◦ (Hooks) • Concurrent introduces the concept of priority in React ~ REACT++ ~ REACT
14. Re-architecture: step 2 • JSI = JavaScript Interface ◦ it's a unified lightweight general purpose API for (theoretically) any JavaScript virtual machine ◦ Decouples JS and VM (=Easy swapping) • JSI unlocks the possibility to use C++ JAVASCRIPT JSC JAVASCRIPT ANY JS* JSI
15. Re-architecture: step 3A • JS can hold direct reference to a Native Module object (via C++ Host Objects), generated when needed • Native module methods invocations don't need to batched anymore: they can be executed synchronously without congesting the “bridge” JSI BRIDGE SHADOW TREE JSON (ASYNC) NATIVE MODULES TURBO MODULES NATIVE(s)
16. Re-architecture: step 3B • Fabric is an effort aimed to modernize the rendering layer of React Native. ◦ Uses C++ for cross-platform "shadow" layer ◦ Shared memory ownership between JS and native (thanks JSI) ◦ Leveraging new React prioritization, it will allow 4 queues: 2 sync & 2 async BRIDGE SHADOW TREE JSON (ASYNC) NATIVE MODULES FABRIC NATIVE(s) JAVASCRIPT
17. Let’s summarize ~ REACT++ JAVASCRIPT NATIVE(s) “When?” • React Concurrent / Suspense ◦ partially already available >=16.6 • JSI ◦ already on master • Turbo Modules ◦ ongoing development in the open • Fabric ◦ ongoing development in the open ◦ currently tested by FB ANY JS* JSI TURBO MODULES FABRIC
18. Let’s summarize - FAQs • Will I have to change my code? ◦ No. It will be a gradual transition - but you can opt-in on the new React features. • Will it solve gesture & navigation? ◦ No: the re-architecture is a foundation that meant to help improve things. See it as an enabler. • How will I know when it’s ready? ◦ It will be properly communicated
19. ONE MORE THING...
20. Re-architecture: step 4 • This is more of a meta-effort: the Lean Core • By moving portions of the current main codebase into separate repositories (ex. WebView), we can increase the overall solidity of the whole codebase: ◦ More people involved ◦ Reduce dead code in your app NATIVE(s) NATIVE(s) -- https://github.com/react-native-community/discussions-and-proposals/issues/6
21. React Native Community • The community has always been active actor in the development of React Native • We want to step up our game by: ◦ Enforcing a set of guidelines for all the packages/repos hosted in the GitHub org ◦ Providing a single place for maintainers to help each other ◦ Setting standards for quality code
22. Conclusions • The re-architecture is going to allow us to reach new performance peaks, via: ◦ JSI ◦ Turbo Modules ◦ Fabric • This re-architecture also enables a wider range of platforms to be targeted (thanks to C++) • The community is one of the best in the dev world
23. THANK YOU! Lorenzo Sciandra @kelset React Native Community -> @ReactNativeComm ...QUESTIONS?