Question

如果我们有一个动态（不是声明式动态创建）的ComponentRef实例，并且在该实例上调用destroy()，将取消订阅已订阅的EventEmitter实例的任何订阅

例如，如果我们有一个output EventEmitter且我们这样订阅：

this.componentRef.instance.output.subscribe(event => console.log(event));

我们打电话给componentRef.destroy()来取消订阅output EventEmitter的事情吗？

总结答案的文章

https://medium.com/@ole.ersoy/subscribing-to-dynamic-component-eventemitters-4f931a5013e3

https://medium.com/@ole.ersoy/cleaning-up-subscriptions-to-dynamic-component-event-emitters-ad08c838c7a8

Answer 1

调用subscribe方法时，将返回一个预订对象。如果我跟踪那个对象。每当Angular破坏组件时，您都必须调用unsubscribe。

E.x：

ngOnDestroy() {
   this.sub.unsubscribe();
}

它不会退订ngOnDestroy()

Answer 2

componentRef有一个onDestroy回调，您可以挂钩以清理订阅

  /**
   * A lifecycle hook that provides additional developer-defined cleanup
   * functionality for the component.
   * @param callback A handler function that cleans up developer-defined data
   * associated with this component. Called when the `destroy()` method is invoked.
   */
  abstract onDestroy(callback: Function): void;

示例

const sub=this.componentRef.instance.output.subscribe(event => console.log(event));
this.componentRef.onDestroy(()=>{
    sub.unsubscribe()
})

ComponentRef.destroy（）方法是否也取消订阅组件事件发射器？

总结答案的文章

2 个答案: