Miscellanies about React Native

• If /android or /ios is missing under project volume:

  react-native upgrade # optional
  react-native eject

• react-native run-ios: xcrun: error: unable to find utility “instruments”, not a developer tool or in PATH
  error Command failed: xcrun instruments -s
  xcrun: error: unable to find utility “instruments”, not a developer tool or in PATH

https://stackoverflow.com/questions/42506068/how-can-i-regenerate-ios-folder-in-react-native-project