# Environment **Environment** is a singleton object created by the framework when the application is started. It provides the **AppStorage** with a series of environment state attributes required by the application. These attributes describe the device environment where the application runs. **Environment** and its attributes are immutable. All attribute values are of the simple type. The following example shows how to obtain the voice environment from **Environment**: ``` Environment.EnvProp("accessibilityEnabled", "default"); var enable = AppStorageGet("accessibilityEnabled"); ``` **accessibilityEnabled** is the default system variable identifier provided by **Environment**. You need to bind the corresponding system attribute to the **AppStorage**. Then, you can use the methods or decorators in the **AppStorage** to access the corresponding system attribute data. ## Environment APIs

key	Parameter	Return Value	Description
EnvProp	key : string defaultValue: any	boolean	Associates this system item with the Appstorage. You are advised to use this API during application startup. If the attribute already exists in the Appstorage, false is returned. Do not use the variables in the AppStorage. Call this method to associate environment variables.
EnvProps	keys: { key: string, defaultValue: any }[]	void	Associates this system item array with the Appstorage.
Keys	Array<string>	number	Returns the associated system item array.

key

Parameter

Return Value

Description

EnvProp

key : string

defaultValue: any

boolean

Associates this system item with the Appstorage. You are advised to use this API during application startup. If the attribute already exists in the Appstorage, false is returned. Do not use the variables in the AppStorage. Call this method to associate environment variables.

EnvProps

keys: {

key: string,

defaultValue: any

}[]

void

Associates this system item array with the Appstorage.

Keys

Array<string>

number

Returns the associated system item array.

## Environment Built-in Environment Variables

key	Type	Description
accessibilityEnabled	boolean	Whether to enable accessibility.
colorMode	ColorMode	Color mode. The options are as follows: ColorMode.LIGHT: light mode. ColorMode.DARK: dark mode.
fontScale	number	Font scale. The value range is [0.85, 1.45].
fontWeightScale	number	Font weight scale. The value range is [0.6, 1.6].
layoutDirection	LayoutDirection	Layout direction. The options are as follows: LayoutDirection.LTR: The direction is from left to right. LayoutDirection.RTL: The direction is from right to left.
languageCode	string	Current system language. The value is in lowercase, for example, zh.