TurboModules
- React Native course
- Expert
- Lesson 4/47
- 5 min
Learn TurboModules and JSI-based modules.
What are TurboModules?
TurboModules are native modules bound to the JS side through JSI. They replace the old NativeModules; modules are loaded lazily, on demand.
A TurboModule is defined by a TypeScript spec file and registered with TurboModuleRegistry.getEnforcing. Codegen produces the C++/Java/Objective-C skeleton from this spec.
The spec file
The TurboModule spec file is a .ts file. It defines an interface extending TurboModule; each method's signature is written there. Codegen reads this file.
The file name should follow Native<Name>.ts; e.g. NativeMath.ts. It usually lives at src/NativeMath.ts.
Practice Write the TurboModule spec
Write a TurboModule spec file named NativeMath.ts. Define a Spec interface extending TurboModule with a method add(a: number, b: number): number. Export it with export.
Starter code
import type { TurboModule } from 'react-native/Libraries/TurboModule/RCTExport';
// Define the Spec interface here
export default TurboModuleRegistry.getEnforcing<Spec>('Math');Sample solution
import type { TurboModule } from 'react-native/Libraries/TurboModule/RCTExport';
import { TurboModuleRegistry } from 'react-native';
export interface Spec extends TurboModule {
add(a: number, b: number): number;
}
export default TurboModuleRegistry.getEnforcing<Spec>('Math');Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Write the TurboModule registration call
const Module = TurboModuleRegistry.____('MyModule');const Module = TurboModuleRegistry.getEnforcing('MyModule');Explanation: getEnforcing returns the module or throws.
2 Match the TurboModule pieces
| Term | Meaning |
|---|---|
Spec file |
TypeScript interface |
getEnforcing |
Fetches module |
Codegen |
Generates C++ skeleton |
NativeModules |
Old system |
3 When are TurboModules loaded?
- On demand (lazy)
- All at app startup
- Only in release builds
- Only on iOS Correct answer
Explanation: TurboModules are loaded lazily on first call.