Expo Constants

GitHub

npm

An API that provides system information that remains constant throughout the lifetime of your app's installation.

expo-constants provides system information that remains constant throughout the lifetime of your app's installation.

Platform Compatibility

Android Device	Android Emulator	iOS Device	iOS Simulator	Web

Installation

Terminal

- npx expo install expo-constants

If you are installing this in an existing React Native app, start by installing expo in your project. Then, follow the additional instructions as mentioned by the library's README under "Installation in bare React Native projects" section.

API

import Constants from 'expo-constants';

Interfaces

`AndroidManifest`

AndroidManifest Properties

Name	Type	Description
versionCode	`number`	Deprecated Use `expo-application`'s `Application.nativeBuildVersion`. The version code set by `android.versionCode` in app.json. The value is set to `null` in case you run your app in Expo Go.

`IOSManifest`

IOSManifest Properties

Name	Type	Description
buildNumber	`null \| string`	The build number specified in the embedded Info.plist value for `CFBundleVersion` in this app. In a standalone app, you can set this with the `ios.buildNumber` value in app.json. This may differ from the value in `Constants.expoConfig.ios.buildNumber` because the manifest can be updated, whereas this value will never change for a given native binary. The value is set to `null` in case you run your app in Expo Go.
model	`null \| string`	Deprecated Moved to `expo-device` as `Device.modelName`. The human-readable model name of this device, e.g. `"iPhone 7 Plus"` if it can be determined, otherwise will be `null`.
platform	`string`	Deprecated Use `expo-device`'s `Device.modelId`. The Apple internal model identifier for this device, e.g. `iPhone1,1`.
systemVersion	`string`	Deprecated Use `expo-device`'s `Device.osVersion`. The version of iOS running on this device, e.g. `10.3`.
userInterfaceIdiom	`UserInterfaceIdiom`	Deprecated Use `expo-device`'s `Device.getDeviceTypeAsync()`. The user interface idiom of this device, i.e. whether the app is running on an iPhone, iPad, Mac or Apple TV.

`NativeConstants`

NativeConstants Properties

Name	Type	Description
appOwnership	`null \| AppOwnership`	Returns `expo`, `standalone`, or `guest`. This property only applies to the managed workflow and classic builds; for apps built with EAS Build and in bare workflow, the result is always `null`.
debugMode	`boolean`	-
deviceName (optional)	`string`	A human-readable name for the device type.
deviceYearClass	`null \| number`	Deprecated Moved to `expo-device` as `Device.deviceYearClass`. The device year class of this device.
easConfig	`null \| EASConfig`	The standard EAS config object populated when using EAS.
executionEnvironment	`ExecutionEnvironment`	-
experienceUrl	`string`	-
expoConfig	`null \| ExpoConfig & { hostUri: string }`	The standard Expo config object defined in `app.json` and `app.config.js` files. For both classic and modern manifests, whether they are embedded or remote.
expoGoConfig	`null \| ExpoGoConfig`	The standard Expo Go config object populated when running in Expo Go.
expoRuntimeVersion	`null \| string`	-
expoVersion	`null \| string`	The version string of the Expo Go app currently running. Returns `null` in bare workflow and web.
getWebViewUserAgentAsync	`() => Promise<null \| string>`	-
installationId	`string`	Deprecated `Constants.installationId` is deprecated in favor of generating your own ID and storing it. An identifier that is unique to this particular device and whose lifetime is at least as long as the installation of the app.
intentUri (optional)	`string`	-
isDetached (optional)	`boolean`	-
isDevice	`boolean`	Deprecated Use `expo-device`'s `Device.isDevice`. `true` if the app is running on a device, `false` if running in a simulator or emulator.
isHeadless	`boolean`	-
linkingUri	`string`	-
manifest	`null \| BareManifest`	Deprecated Use `Constants.expoConfig` instead, which behaves more consistently across EAS Build and EAS Update. Classic manifest for Expo apps using classic updates and the updates embedded in builds. Returns `null` in bare workflow and when `manifest2` is non-null.
manifest2	`null \| NewManifest`	Manifest for Expo apps using modern Expo Updates from a remote source, such as apps that use EAS Update. Returns `null` in bare workflow and when `manifest` is non-null. `Constants.expoConfig` should be used for accessing the Expo config object.
nativeAppVersion	`null \| string`	Deprecated Use `expo-application`'s `Application.nativeApplicationVersion`. The Info.plist value for `CFBundleShortVersionString` on iOS and the version name set by `version` in app.json on Android at the time the native app was built.
nativeBuildVersion	`null \| string`	Deprecated Use `expo-application`'s `Application.nativeBuildVersion`. The Info.plist value for `CFBundleVersion` on iOS (set with `ios.buildNumber` value in app.json in a standalone app) and the version code set by `android.versionCode` in app.json on Android at the time the native app was built.
platform (optional)	`PlatformManifest`	-
sessionId	`string`	A string that is unique to the current session of your app. It is different across apps and across multiple launches of the same app.
statusBarHeight	`number`	The default status bar height for the device. Does not factor in changes when location tracking is in use or a phone call is active.
systemFonts	`string[]`	A list of the system font names available on the current device.
systemVersion (optional)	`number`	-

`PlatformManifest`

PlatformManifest Properties

Name	Type	Description
android (optional)	`AndroidManifest`	-
detach (optional)	`{ scheme: string }`	-
developer (optional)	`string`	-
hostUri (optional)	`string`	-
ios (optional)	`IOSManifest`	-
scheme (optional)	`string`	-
web (optional)	`WebManifest`	-