Generates TypeScript types for the native API an Expo module exports to JavaScript. It scans the package's Swift sources for @ExpoModule, @SharedObject, @Record, and @Union types annotated with the Expo Modules macros, and for Enumerable enums, and writes them to one TypeScript file per package, src/native.types.ts by default, which the package compiles along with its other sources. Modules extend NativeModule and shared objects extend SharedObject, both imported from expo. The @Event declarations of a class become an exported <Name>Events type passed to its base class, the same shape hand-written modules use. A shared object without a @JS init gets a private constructor, since only native code creates its instances. Enumerable enums become TS enums with the Swift case names and raw values, and @Union types the union of their member types. The command leaves the file untouched when it already holds the generated content, only replaces a file that starts with its own header, so it never overwrites a hand-written file, and removes such a file when the package no longer exports anything.

expo-modules generate-types packages/expo-video

The scanner is a macOS binary, so this command runs on macOS only. Support for Linux is planned.

Options:

-o, --out <path>: the TypeScript file to write, relative to the package directory. Defaults to src/native.types.ts.
--scanner <path>: path to the Expo Modules scanner executable. Defaults to the scanner bundled with the CLI.
--check: verify that the file is up to date without writing it. Exits with code 1 when the file is missing, outdated, or no longer needed, so a CI job can catch a stale committed file.

After writing, the command lists every declaration with its kind, TypeScript name, and the Swift file it came from, grouped by file. A Swift type the scanner cannot express in TypeScript renders as unknown, and the command prints a warning naming the Swift file and member so the gap is visible.

The scan skips node_modules, Pods, .build, and .git, and also test and example directories (Tests, UITests, __tests__, __mocks__, example, examples, e2e), whose sources are not part of the package's product. A package that only declares modules in such directories, like the test fixtures in expo-modules-core, therefore generates nothing.