# Custom Property

You can set custom properties on components. These custom properties can be obtained on their corresponding FrameNodes, allowing for more flexible component management.

>  **NOTE**
>
>  The initial APIs of this module are supported since API version 12. Updates will be marked with a superscript to indicate their earliest API version.

## customProperty

customProperty(name: string, value: Optional\<Object>)

Sets a custom property for this component. This API does not work for [custom components](../../../quick-start/arkts-create-custom-components.md#creating-a-custom-component).

**Widget capability**: This API can be used in ArkTS widgets since API version 12.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.ArkUI.ArkUI.Full

**Parameters** 

| Name | Type                                                | Mandatory | Description                                                        |
| ------ | ---------------------------------------------------- | ---- | ------------------------------------------------------------ |
| name  | string | Yes  | Name of the custom property. |
| value  | Optional\<Object> | Yes  | Value of the custom property. |


## Optional<sup>12+</sup>

Optional\<T>

Defines the Optional type. The value can be **undefined**.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.ArkUI.ArkUI.Full

**Widget capability**: This API can be used in ArkTS widgets since API version 12.

## Example
```ts
// xxx.ets
import { FrameNode, UIContext } from '@kit.ArkUI';

@Entry
@Component
struct CustomPropertyExample {
  build() {
    Column() {
      Text('text')
      Button('print').onClick(() => {
        const uiContext: UIContext = this.getUIContext();
        if (uiContext) {
          const node: FrameNode | null = uiContext.getFrameNodeById("Test_Column") || null;
          if (node) {
            for (let i = 1; i < 4; i++) {
              const key = 'customProperty' + i;
              const property = node.getCustomProperty(key);
              console.log(key, JSON.stringify(property));
            }
          }
        }
      })
    }
    .id('Test_Column')
    .customProperty('customProperty1', {
      'number': 10,
      'string': 'this is a string',
      'bool': true,
      'object': {
        'name': 'name',
        'value': 100
      }
    })
    .customProperty('customProperty2', {})
    .customProperty('customProperty2', undefined)
    .width('100%')
    .height('100%')
  }
}
```