RxJS: Why memory leaks occur when using a Subject

[Andrei0872]

inDepthDev link.

[gogumachu]

Hello, I enjoyed reading your article.
I have one question.
Exactly what does the following case mean in the case where 'unsubscribing is not necessary' ??
Does that means the component declares Subject as a member variable and the component is destroyed by moving the router?

[Andrei0872]

Hi @gogumachu,

In the router's situation, I was mainly referring to this detach method:

  detach(): ComponentRef<any> {
    if (!this.activated) throw new Error('Outlet is not activated');
    this.location.detach();
    const cmp = this.activated;
    this.activated = null;
    this._activatedRoute = null;
    this.detachEvents.emit(cmp.instance);
    return cmp;
  }

which is called when the current route is destroyed and replaced by a new one, as a result of a successful navigation. As you can see, the current activated route, which has some properties that are BehaviorSubjects, is nulled out. I admit that my wording could've been more accurate, the container which holds the Subject property is nulled out, not the Subject itself.

But anyway, the gist is that the Subject property can no longer be referenced, meaning there is no way it can send any notifications, so the Subject instance and its properties can be safely garbage-collected.

I'm apologize for the confusion, I will amend it as soon as possible. Thanks!

[gogumachu]

Oh I understand what you mean! Thank you for your response :)