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. A type nested in another type is declared under its own name, without the names of the types around it (Encoding for DigestOptions.Encoding). 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.

The command scans with the expo-modules-macros version that the package's expo-modules-core depends on, the same version the iOS build compiles the macros with. It finds that version through the expo package, so expo must be installed in the package, which every Expo module has as a peer dependency.

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 that ships with the expo-modules-macros version that expo-modules-core depends on.
--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 Exits with code 1 when the file is missing, outdated, or no longer needed, so a CI job can catch a stale committed file.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.