Expo 常量

一个提供系统信息的 API，这些信息在应用安装的整个生命周期内保持不变。

Android

iOS

tvOS

Web

Included in Expo Go

GitHub

npm

更新日志

Recommended version:

~18.0.14

expo-constants 提供在应用安装生命周期内保持不变的系统信息。

安装

Terminal

- npx expo install expo-constants

- yarn expo install expo-constants

- pnpm expo install expo-constants

- bun expo install expo-constants

If you are installing this in an existing React Native app, make sure to install expo in your project.

API

import Constants from 'expo-constants';

Types

`AndroidManifest`

Android

Type: Record<string, any> extended by:

Property	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: ClientScopingConfig

`EASConfig`

Android

iOS

tvOS

Web

Type: EASConfig

`ExpoGoConfig`

Android

iOS

tvOS

Web

Type: ExpoGoConfig

`ExpoGoPackagerOpts`

Android

iOS

tvOS

Web

Type: ExpoGoPackagerOpts

`IOSManifest`

iOS

Type: Record<string, any> extended by:

Property	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: ManifestAsset

`ManifestExtra`

Android

iOS

tvOS

Web

Type: ManifestExtra

`NativeConstants`

Android

iOS

tvOS

Web

Type: Record<string, any> extended by:

Property	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	`EASConfig \| 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	`ExpoGoConfig \| 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:

Property	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"