SystemCapability (SysCap) is a standalone feature in the OpenHarmony system.
SystemCapability (SysCap) is a standalone feature in the operating system.
Before using an API for development, you are advised to familiarize yourself with [SysCap](syscap.md), and then consult the following tables to see whether the SysCap set required for the API is supported by the target device type.
> **NOTE**
>
> The **default** device type represents an OpenHarmony device with comprehensive functions and most common capabilities. When you are not sure about the capability set of the target device, you can use the **default** type for development.
>
> The **default** device type represents an OpenHarmony device with comprehensive functions and most common capabilities. If you are not sure about the capability set of the target device, you can use the **default** type for development.
## SystemCapability.ArkUI.ArkUI.Full
...
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@@ -273,7 +273,7 @@ GNSS hardware capabilities
## SystemCapability.Location.Location.Lite
Lite device capabilities of the location service
Location service for mini-, small- and standard-system devices
#### 1. Restrictions on Using Component Decorators
Component decorators @Component, @Entry, @Preview, and @CustomDialog apply only to structs, not classes.
**Example**
```
@Component
// ERROR:The '@Component' decorator can only be used with 'struct'.
class Index {
build() {
}
}
```
**Change Impact**
If @Component, @Entry, @Preview, or @CustomDialog is used to decorate components other than structs, a compile time error will occur.
**Key API/Component Changes**
N/A
**Adaptation Guide**
Use @Component, @Entry, @Preview, and @CustomDialog to decorate only structs.
#### 2. Restrictions on Using Component Member Variable Decorators
Component member variable decorators @State, @Prop, @Link, @Provide, @Consume, @ObjectLink, @StorageLink, @StorageProp, @LocalStorageLink, @LocalStorageProp, @Watch, and @BuilderParam can decorate only the member variables of structs.
**Example**
```
@Component
class Index {
// ERROR: The '@State' decorator can only be used with 'struct'.
@State message: string = 'Hello world'
build() {
}
}
```
**Change Impact**
If any of the aforementioned component member variable decorators is used to decorate a member variable of components other than structs, a compile time error will occur.
**Key API/Component Changes**
N/A
**Adaptation Guide**
Use the aforementioned component member variable decorators to decorate only the member variables of structs.
