Could not resolve project :react-native-fs. code example
Example: could not resolve module fs react native
npm install rn-nodeify
Then in package.json file, add the following line in "scripts" to specify which modules you want to include in your RN project. For example, I used fs, crypto and https, and the line goes
"postinstall": "node_modules/.bin/rn-nodeify --install crypto,fs,https --hack"