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Expo Constants

GitHub

npm

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

Android

iOS

tvOS

Web

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

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';

Types

`AndroidManifest`

Android

Type: Record<string, any> extended by:

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.

`ClientScopingConfig`

Android

iOS

tvOS

Web

Type: ClientScopingConfigForReExport

`EASConfig`

Android

iOS

tvOS

Web

Type: ManifestsEASConfig

`ExpoGoConfig`

Android

iOS

tvOS

Web

Type: ManifestsExpoGoConfig

`ExpoGoPackagerOpts`

Android

iOS

tvOS

Web

Type: ExpoGoPackagerOptsForReExport

`IOSManifest`

iOS

Type: Record<string, any> extended by:

Name	Type	Description
buildNumber	`string \| null`	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	`string \| null`	Deprecated Moved to `expo-device` as `Device.modelName`. The human-readable model name of this device. For example, `"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. Example `iPhone1,1`
systemVersion	`string`	Deprecated Use `expo-device`'s `Device.osVersion`. The version of iOS running on this device. Example `10.3`
userInterfaceIdiom	`UserInterfaceIdiom`	Deprecated Use `expo-device`'s `Device.getDeviceTypeAsync()`. The user interface idiom of the current device, such as whether the app is running on an iPhone, iPad, Mac or Apple TV.

`Manifest`

Android

iOS

tvOS

Web

Type: ExpoUpdatesManifest

`ManifestAsset`

Android

iOS

tvOS

Web

Type: ManifestAssetForReExport

type re-exports to prevent breaking change

`ManifestExtra`

Android

iOS

tvOS

Web

Type: ManifestExtraForReExport

`NativeConstants`

Android

iOS

tvOS

Web

Type: Record<string, any> extended by:

Name	Type	Description
appOwnership	`AppOwnership \| null`	Deprecated Use `Constants.executionEnvironment` instead. Returns `expo` when running in Expo Go, otherwise `null`.
debugMode	`boolean`	Returns `true` when the app is running in debug mode (`__DEV__`). Otherwise, returns `false`.
deviceName (optional)	`string`	A human-readable name for the device type.
deviceYearClass	`number \| null`	Deprecated Moved to `expo-device` as `Device.deviceYearClass`. The device year class of this device.
easConfig	`ManifestsEASConfig \| null`	The standard EAS config object populated when using EAS.
executionEnvironment	`ExecutionEnvironment`	Returns the current execution environment.
experienceUrl	`string`	-
expoConfig	`ExpoConfig & { hostUri: string } \| null`	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	`ManifestsExpoGoConfig \| null`	The standard Expo Go config object populated when running in Expo Go.
expoRuntimeVersion	`string \| null`	Nullable only on the web.
expoVersion	`string \| null`	The version string of the Expo Go app currently running. Returns `null` in bare workflow and web.
getWebViewUserAgentAsync	`() => Promise<string \| null>`	Gets the user agent string which would be included in requests sent by a web view running on this device. This is probably not the same user agent you might be providing in your JS `fetch` requests.
intentUri (optional)	`string`	-
isDetached (optional)	`boolean`	-
isHeadless	`boolean`	Returns `true` if the app is running in headless mode. Otherwise, returns `false`.
linkingUri	`string`	-
manifest2	`ExpoUpdatesManifest \| null`	Manifest for Expo apps using modern Expo Updates from a remote source, such as apps that use EAS Update. `Constants.expoConfig` should be used for accessing the Expo config object.
platform (optional)	`PlatformManifest`	Returns the specific platform manifest object. Note: This is distinct from the `manifest` and `manifest2`.
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`

Android

iOS

tvOS

Web

Type: Record<string, any> extended by:

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`	-

`WebManifest`

Web

Type: Record<string, any>

Enums

`AppOwnership`

Android

iOS

tvOS

Web

Deprecated Use Constants.executionEnvironment instead.

`Expo`

AppOwnership.Expo ＝ "expo"

The experience is running inside the Expo Go app.

`ExecutionEnvironment`

Android

iOS

tvOS

Web

`Bare`

ExecutionEnvironment.Bare ＝ "bare"

`Standalone`

ExecutionEnvironment.Standalone ＝ "standalone"

`StoreClient`

ExecutionEnvironment.StoreClient ＝ "storeClient"

`UserInterfaceIdiom`

Android

iOS

tvOS

Web

Current supported values are handset, tablet, desktop and tv. CarPlay will show up as unsupported.

`Desktop`

UserInterfaceIdiom.Desktop ＝ "desktop"

`Handset`

UserInterfaceIdiom.Handset ＝ "handset"

`Tablet`

UserInterfaceIdiom.Tablet ＝ "tablet"

`TV`

UserInterfaceIdiom.TV ＝ "tv"

`Unsupported`

UserInterfaceIdiom.Unsupported ＝ "unsupported"