react-native-module-codegen.md

React Native Module Codegen

A brief overview of how React Native codegen handles stuff

• I asked AI for this, so it's worth looking into the official docs of codegen

1. The JavaScript Layer (getEnforcing)

This is the "Request."

• Where: Your TypeScript Spec file.

• The Code: TurboModuleRegistry.getEnforcing('GalaxyGate')

• Fragility: If this string doesn't match the name registered in the Native layer, JS will look for a key that doesn't exist.

2. The Native Layer (Registration)

This is the "Provider."

• iOS: Inside your .mm (Objective-C++) file, you have a macro: return "GalaxyGate"; (or RCT_EXPORT_MODULE(GalaxyGate)).

• Android: Inside your GalaxyGateModule.java, you return the name: public String getName() { return "GalaxyGate"; }

• Fragility: This is what "announces" the module to the app on boot-up. If this is UniversePortal but JS asks for GalaxyGate, the app will find nothing.

3. The Discovery Layer (Autolinking)

This is the "Bridge Builder" we discussed.

• The File: GalaxyGate.podspec

• The package.json: "name": "galaxy-gate"

• The codegenConfig: "name": "GalaxyGateSpec"

• Fragility: If you rename the .podspec file but don't update the s.name inside the file, CocoaPods will get confused and might not link the source files correctly.

Naming

• Two specific names:
  • GalaxyGateSpec (The "Blueprint"): Name for generated C++ and Java code
  • GalaxyGate (The "ID"): Runtime string for handshakes between JS and Native

Layer	Name Pattern	Example File/String
Your Source File	Native<Name>.ts	NativeGalaxyGate.ts
Codegen Output (C++)	Native<Name>Spec.h	NativeGalaxyGateSpec.h
Java Interface	Native<Name>Spec.java	NativeGalaxyGateSpec.java
The Handshake ID	<Name>	GalaxyGate