Using a module

npm install @ng-native/expo
npm install expo-battery   # only if you're injecting Battery

One entry point per module

Most of these services have their own entry point - @ng-native/expo/battery, @ng-native/expo/haptics, and so on, one file per module - rather than being re-exported from the package's own root. That is so that importing haptics never pulls in the video player:

import { Battery } from '@ng-native/expo/battery';
import { Haptics } from '@ng-native/expo/haptics';
import { Storage, SecureStorage } from '@ng-native/expo/store';

Each name is a type as well as a token, so inject(Clipboard) and private clipboard: Clipboard both work. Each service is one file: a @Service() class that reaches its module through an injected source token - an InjectionToken carrying its own factory - so there is nothing to provide and nothing to register. Injecting it is the whole setup, and a service nobody injects is never constructed.

What happens without the module installed

A service reaches for its module when it is first injected, with a require() inside a factory rather than a static import: a file with a static import ... from 'expo-battery' would be unloadable by Node at all - Expo's build output uses extensionless relative imports, and what it pulls in reaches react-native, which is Flow.

Where the module exists for the platform the app is on, a missing one is a mistake with a fix, so the service throws a MissingModuleError rather than quietly doing nothing. That covers a package that was never installed, and the more common case of one that was installed after the app was last built: a development build, and Expo Go, contain only the native modules they were built with. The message names the module and the commands to run:

expo-haptics is not in this build of the app. Install it with "npx expo install expo-haptics",
then rebuild the app ("npx expo run:ios", or a new EAS build): a development build, and Expo Go,
contain only the native modules they were built with.

MissingModuleError is exported from @ng-native/expo, with a module property naming the package, for an app that wants to catch it and show something of its own.

Where the module cannot exist, the service goes inert instead: an iOS-only module such as Sign in with Apple on Android, a service on the web, and a test in Node, where there is no platform at all. Code shared across platforms, and a test that provides no fake, keep working. Inert means reporting nothing rather than throwing: a level of 1, a status of 'unknown', a method that resolves to null or an empty list. Each module's own page says what its service does in both cases. A few cannot be inert, because an empty answer would be a wrong one: a database or a player throws on the web as well, and Crypto throws wherever it has no module, since an empty identifier or hash looks right and is not.

What is on the bare import

A handful of exports are not bound to one optional module, so they live on @ng-native/expo itself rather than behind an entry point: Permission, registerExpoView, registerExpoViews, registerNativeViews and registerExpoUiViews (see Native views and Expo UI), and nativeState (also on the Expo UI page).

Where everything else lives

Every module has its own page, grouped by what it is for, from the overview.