1# Unsubscribing from Common Events in Dynamic Mode 2 3<!--Kit: Basic Services Kit--> 4<!--Subsystem: Notification--> 5<!--Owner: @peixu--> 6<!--Designer: @dongqingran; @wulong158--> 7<!--Tester: @wanghong1997--> 8<!--Adviser: @huipeizi--> 9 10## When to Use 11 12After a service is finished in the dynamic mode, the subscriber should proactively unsubscribe from the event. You can call [unsubscribe()](../../reference/apis-basic-services-kit/js-apis-commonEventManager.md#commoneventmanagerunsubscribe) to unsubscribe from a common event that is no longer required. 13 14 15## Available APIs 16 17| API| Description| 18| -------- | -------- | 19| [unsubscribe](../../reference/apis-basic-services-kit/js-apis-commonEventManager.md#commoneventmanagerunsubscribe)(subscriber: CommonEventSubscriber, callback?: AsyncCallback<void\>) | Unsubscribes from a common event.| 20 21 22## How to Develop 23 241. Import the **commonEventManager** module. 25 26 ```ts 27 import { BusinessError, commonEventManager } from '@kit.BasicServicesKit'; 28 import { hilog } from '@kit.PerformanceAnalysisKit'; 29 30 const TAG: string = 'ProcessModel'; 31 const DOMAIN_NUMBER: number = 0xFF00; 32 ``` 33 342. Subscribe to an event by following the procedure described in [Subscribing to Common Events in Dynamic Mode](common-event-subscription.md). 35 363. Call [unsubscribe()](../../reference/apis-basic-services-kit/js-apis-commonEventManager.md#commoneventmanagerunsubscribe) in **CommonEvent** to unsubscribe from an event. 37 38 ```ts 39 // The subscriber object is created during event subscription. 40 if (subscriber !== null) { 41 commonEventManager.unsubscribe(subscriber, (err: BusinessError) => { 42 if (err) { 43 hilog.error(DOMAIN_NUMBER, TAG, `Failed to unsubscribe. code is ${err.code}, message is ${err.message}`); 44 } else { 45 hilog.info(DOMAIN_NUMBER, TAG, `Succeeded in unsubscribing.`); 46 subscriber = null; 47 } 48 }) 49 } 50 ``` 51