Expo

https://docs.expo.dev

Creating

npx create-expo-app@latest

APIs

• Insecure Storage
• Notifications
• Secure Storage

Environment

https://docs.expo.dev/workflow/development-mode/

• __DEV__ is truthy in dev mode and falsy in prod mode
• You can toggle prod mode in web UI
• Publish is prod mode

Upgrading

• Update the version of expo in package.json
• npm install -g expo-cli
• expo-cli upgrade
• expo-cli doctor

Terminology

• Project Types
  • Expo Go: a limited sandbox without custom native modules. Intended for testing out Expo, not for long-term projects.
  • Development Build: a build of your own app with developer tools. Supports custom native modules. Intended for production projects. Make a development build by including the expo-dev-client library in the project.
    • Built with EAS: requires an EAS account (although you can do a “local” EAS build)
    • Built with your own tools
• Build types
  • Automatically configured by EAS (eas build:configure)
    • Development: configured as a development client (which probably means loading JS from Metro)
    • Preview: internal distribution
    • Production: non-internal distribution (including TestFlight?)
• Commands
  • eas build [--local] - runs a build thorough EAS, on their servers by default (paid), or local (free)
  • eas build:run -p [ios|android] [--path=] - install a build on simulator/emulator, either from EAS or a specific local file
  • expo prebuild - generates native project directories but does not build
  • expo run:[ios|android] - builds and runs the development build
  • expo start [--ios|--android|--web] - starts Metro

Clear Cache

• yarn prebuild --clean - removes node_modules/ios/android
  • rm -fr ./ios
• yarn start -c - clears bundler cache
• In Xcode, “Clean Build Folder Immediately” (necessary even if you remove the iOS folder, as the build cache is reused)

Developer Menu

• iOS: Cmd-Ctrl-i
• Android: press m in Metro terminal