Few days ago, last iOS builds don’t work with the following error: error: Build input file cannot be found: '/Users/vagrant/git/node_modules/react-native/third-party/double-conversion-1.1.5/src/strtod.cc'
The problem is because we use Stack with stable channel. Apple did release iOS SDK 12, then inside stack, Xcode upgraded to version 10, and only React Native 0.57+ is compatible with this Xcode Version.
Changing to iOS stack with Xcode 9.4.x resolves the problem.