This is a guide on how to reverse engineer the Anova Android APK, which should be generalisable for any Android React Native application.
Head to the apkpure anova download page and get the latest version of the Android (3.3.9 at time of writing).
APKTool is a tool to reverse engineer 3rd party apps follow the Installation Instructions for your operating system.
i.e. for Mac with Homebrew
brew install apktool
Then to decompile the previously downloaded APK
apktool d Anova\ Culinary_v3.3.9_apkpure.com.apk
The decompiled app code contains an index.android.bundle which is React Native source code, however it is extremely hard to read. Therefore need to use react-native-decompiler to automate the hard work!
git clone https://github.com/richardfuca/react-native-decompiler.git
cd react-native-decompiler
npm start -- -i ../Anova\ Culinary_v3.3.9_apkpure.com/assets/index.android.bundle -o ../android-js/output
Note this may take awhile to complete
Which will then create a folder android-js/output with a series of numbered js files from 0 to 2267 with some missing