Introduction to React Native Performance

* Given in ReactNative TLV Meetup on July 20, 2016

React Native holds great promise in terms of excellent developer experience with Javascript and code reuse between platforms. The big question is — do these benefits come at the price of performance? How well can React Native hold its own against purely native implementations?

https://medium.com/@talkol/performance-limitations-of-react-native-and-how-to-overcome-them-947630d7f440#.x4l4xr32i

Transcript

1. Introduction to React Native Performance LIMITATIONS AND HOW TO OVERCOME THEM linkedin/talkol github.com/talkol @koltal talkol@wix.com
2. TAL KOL Hi. Mobile Apps Lead Architect at Wix.com
3. The Promise for Cross Platform 01
4. JavaScript THE HOLY GRAIL OF CROSS PLATFORM LANGUAGES This really isn’t a new concept.. Why didn’t it catch on?
5. Performance
6. React Native “LEARN ONCE, WRITE ANYWHERE” WITH REACT AND JAVASCRIPT Promising pedigree… But does it measure up to purely native apps?
7. UINavigationController UIImageView UISwitch UITabBarController UIBarButtonItem
8. Diving Into React Native 02
9. The JavaScript Realm The Native Realm The Bridge React Native Architecture JSCore (VM) Single Thread Main UI Thread Other BG Threads
10. The JavaScript Realm The Native Realm The Bridge Developer Experience Javascript One JS Bundle Business Logic ObjC+Swift / Java IPA / APK The Framework
11. The JavaScript Realm The Native Realm The Bridge Performance? ✔ ✔ ✖
12. Keep passes over the bridge to a minimum!
13. Obvious Pitfalls WHERE MOST OF THE COMPETITION LOST THE BATTLE Synchronous updates between realms Don’t we need that for consistency?
14. React Native HANDLES THIS SURPRISINGLY WELL OUT-OF-THE-BOX, YAY React.js solves a similar problem on the web Updates between realms are async!
15. Where Performance Breaks Down 03
17. Set state from JS on every touch event 1 Swipeable
18. Data crosses the bridge on every frame!
19. What can we do? LET’S PULL OUT THE BIG GUNS In RN we can move any component to native How can we reduce bridge traffic?
21. Implement the Swipeable container handling touch events in native 2 Swipeable
22. Good but not ideal WE CAN PROBABLY DO BETTER Need native skillset to fix this (or open source) We keep 10% native devs for this purpose
23. React Native doesn’t mean the end of native
24. Declare interaction in JS, and send it over the bridge to a native driver 3 declare driver
25. The Future of RN SOLVING MORE AND MORE SCENARIOS WITHOUT NATIVE CODE JS API that reduces passes over the bridge Declarative nature of React is a big help
26. DEMO Get The Full Code github.com/wix/ rn-perf-experiments