是否有必要取消订阅 Angular Form statusChanges/valueChanges observable? [英] Is it necessary to unsubscribe Angular Form statusChanges/valueChanges observable?

问题描述

通过深入研究角度形式的实现，我发现可观察到的角度形式 valueChanges/statusChanges 是 EventEmitters.是否有必要取消订阅这些 observable?因为当单独使用 EventEmitters 时，我们不会取消订阅?

By dig into the angular form implementation I found the angular form valueChanges/statusChanges observable are EventEmitters. Is it necessary to unsubscribe these observables? since when use EventEmitters alone we don't unsubscribe?

_initObservables() {
    (this as{valueChanges: Observable<any>}).valueChanges = new EventEmitter();
    (this as{statusChanges: Observable<any>}).statusChanges = new EventEmitter();
}

推荐答案

如果不再需要通知，取消订阅始终是一个好习惯.大多数情况下，您不一定可以放入 ngDestroy() 函数.

It is always a good practice to unsubscribe if notification is no longer required. Most of the time you can put into ngDestroy() function not necessarily.

是否总是需要取消订阅?不，如果 EventEmitter 或 Subject 或 Observable 在 Subscription 所在的相同范围(组件或服务)中，则没有需要销毁，因为所有的所有引用都将被完全删除.

Is it always required to Unsubscribe ? No, If EventEmitter or Subject or Observable in same scope (Component or Service ) where Subscription is, then no need to destroy since all reference for all will be removed altogether.

简而言之，如果 Subscription 和 Observable 的范围不同，请确保 Observable 是 unsubscribe.

In short, make sure Observable is unsubscribe if scope are different for Subscription and Observable.

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