Notes On How React Native Helps Companies Build Better Mobile Apps

These are my notes on the recent React Native panel in the F8 2018 Facebook developer conference. Watch the original video here.

Where is it used

• Facebook — Marketplace, Jobs, Safety Check etc
• Skype — Skype app
• TaskRabbit — Tasker app
• Postlight — Audubon Bird Guide
• CondeNast — Vogue iOS app

Code reuse between multiple platforms

• Facebook: ~93%
• Skype: 85–90%
• TaskRabbit: ~86%
• Postlight: 90–95%

Why was it chosen

Facebook

• Platform specific codebases result in
• Developers hitting different snags
• Each platform moving in different speeds
• Getting out of sync
• Doing same things twice
• Polish/optimization doesn’t get done uniformly in both platforms

Skype

• Platforms: iOS, Android, Windows, Mac, Linux — Using ReactNative or Electron+React
• Before ReactNative
• 7 devs and 7 product owners for each platform across multiple timezones
• Main issue was communication between different platforms in different timezones
• After ReactNative
• Moved from platform specific teams to feature squads that focus on delivering features across different platforms
• Feature squads reduce the communication challenges and improve development velocity
• Reduces implementation discrepancies in different platforms
• Got transferable knowledge as all the teams speak the same language
• Easy to ramp up squads for new features and ramp down squads for other features
• Ramp up time is almost zero as there’s a single language used
• Lost good developers
• Focus on hiring generalists
• React — Same UI description language and layout semantics for all platforms
• React — Everything is encapsulated in a component as opposed to code scattered across different layers
• Uses ReactXP

TaskRabbit

• Before ReactNative
• 3 devs on each mobile platform
• After ReactNative
• 2 person team moving faster than the 6 person team
• Business logic lives in a single place and bugs gets fixed for both platforms at same time
• Helps in hiring

Postlight

• Postlight has React (web) experience
• 1.5 devs, completed before deadline and under budget

CondeNast

• CondeNast is a JS shop, so using ReactNative to leverage that experience
• Why replace Swift with JS?
• Declarative layouts with JSX
• Writing layouts in Swift is hard
• Iterate very rapidly
• Lower the barrier to create layouts
• Frees developers from working on “pixel pushing”
• Gives them time to focus on harder and interesting things

Lessons learned

Postlight

• Was able to do performance tuning for low-end devices targetting Indian market
• ReactNative is not prescriptive and makes it possible to drop out of ReactNative and use native modules when needed
• Ran into performance issues when you don’t expect the same with native modules (long scrolling lists etc)

CondeNast

• Being early adopter
• Going through multiple ReactNative version bumps is tough
• Better suited for apps that are under active development as batching several updates at once is painful

Originally published in sheshbabu.com