How to force call `super.ngOnDestroy`

Question

I have an abstract class that helps in avoiding repetitive code (to unsubscribe observables), it looks like:

export abstract class SubscriptionManagmentDirective implements OnDestroy {
  componetDestroyed = new Subject<void>()

  constructor() {}

  ngOnDestroy(): void {
    this.componetDestroyed.next()
    this.componetDestroyed.unsubscribe()
  }
}

In some cases it happened that I override ngOnDestroy and forget to call super.ngOnDestroy() and then subscriptions go wild. I added a unit test to the extending components to test that un-subscriptions has been called, but to do so I have to actually remember to add them.

My question is,

• is there a way to force that super.ngOnDestroy() is called whenever the component is extended?
• or is there a way to write a unit test for the abstract class that would be tested on any component that extend that class?

Any help would be appreciated, thanks.

Answer 1

I think the best approach to this would be adding "noImplicitOverride": true to your tsconfig. It won't necessarily help you remember to call a super method but it will force you to be explicit about overriding methods, throwing a compilation error in cases where you override a method without using the override keyword. It is then up to the developer to decide if the super method needs to be called or not.

https://www.typescriptlang.org/tsconfig#noImplicitOverride