TypeScript is the default language of a new React Native 36,878 app. The SDK 57 create-expo-app template writes .tsx screens, pins typescript ~6.0.3 and @types/react ~19.2.2, and ships a tsconfig.json that extends expo/tsconfig.base with strict: true; the Community CLI template extends @react-native/typescript-config. Front-End Web Development teaches the language itself, so this section covers only what React Native adds: where checking happens, typed screens and routes, the Strict TypeScript API, Codegen specs, and a strict migration of BookNest.