Adding modularity to your React Native library

React Native Permissions checks and requests device permissions on iOS, Android, and Windows. On iOS, apps must describe why they use each permission, and reviewers may reject an app if its code can request permissions that the app does not need. Some users responded by maintaining forks with unwanted permission code removed.

With React Native 0.60 and CocoaPods integration, Acthernoene first explored using subspecs to link only the needed permission files. Autolinking made that approach impractical, so the team tried separate pods for each permission, with a shared core exposing `check` and `request` methods. Xcode caching sometimes kept newly added permissions from being detected, while framework builds hid the files the core needed to inspect.

The separate pod approach created a difficult developer experience. The team built a React Native CLI plugin that changed the podspec to include selected permission files, but users had to rerun it after deleting `node_modules`, and package hoisting caused problems in monorepos.

To address those issues, Acthernoene rewrote the setup script in Ruby so CocoaPods could run it before installation. Developers load the script in the Podfile and call `setup_permissions`, which updates the library specs based on the chosen permissions. This removed the need to rerun the setup after deleting `node_modules` and fixed the hoisting issue.

Acthernoene says software that combines technologies and platforms may take several attempts to get right. He encourages users to be empathetic toward open source maintainers and contribute where they can, including documentation and issue follow-up.