1# Custom Component Built-in APIs 2 3Custom component built-in APIs are APIs predefined on the base class of custom components in the ArkUI framework. You can call these APIs on the instance of a custom component to obtain information, such as the UI context, about the instance. 4 5> **NOTE** 6> 7> The initial APIs of this module are supported since API version 11. Newly added APIs will be marked with a superscript to indicate their earliest API version. 8> 9 10## getUIContext 11 12getUIContext(): UIContext 13 14Obtains the **UIContext** instance. 15 16**System capability**: SystemCapability.ArkUI.ArkUI.Full 17 18**Return value** 19 20| Type | Description | 21| --------------------------------------------------------- | ----------------------- | 22| [UIContext](../apis/js-apis-arkui-UIContext.md#uicontext) | **UIContext** instance obtained.| 23 24**Example** 25 26```ts 27import { UIContext } from '@ohos.arkui.UIContext'; 28 29@Entry 30@Component 31struct MyComponent { 32 aboutToAppear() { 33 let uiContext: UIContext = this.getUIContext(); 34 } 35 36 build() { 37 // ... 38 } 39} 40``` 41 42## queryNavDestinationInfo 43 44queryNavDestinationInfo(): NavDestinationInfo | undefined; 45 46Obtains the **NavDestinationInfo** instance. 47 48**System capability**: SystemCapability.ArkUI.ArkUI.Full 49 50**Return value** 51 52| Type | Description | 53| -------------------------------------------------------------------------- | --------- | 54| [NavDestinationInfo](../apis/js-apis-arkui-observer.md#navdestinationinfo) \| undefined | **NavDestinationInfo** instance obtained.| 55 56**Example** 57 58```ts 59import observer from '@ohos.arkui.observer'; 60 61@Entry 62@Component 63struct MyComponent { 64 aboutToAppear() { 65 let info: observer.NavDestinationInfo | undefined = this.queryNavDestinationInfo(); 66 } 67 68 build() { 69 // ... 70 } 71} 72``` 73