console.log doesn't work with react-native

You can also see the console.log() outputs using these commands:

$ react-native log-android
$ react-native log-ios

Note: It also works to debug native errors, for example when you have a blank screen and metro bundler doesn't show errors neither.

For more information you can check this out

Don't know if I correctly understand your question (because of my english), but you can try this:

Run adb logcat *:S ReactNative:V ReactNativeJS:V in a terminal to see your Android app's logs.

Taken from Using adb logcat for React Native Debugging