Rule "no-life-cycle-call" does not allow for subclassing

[jscharett]

If I extend a component and I override a lifecycle hook, this rule prevents me from calling the super method. While I agree with the premise of the rule, it should, however, allow me to call the super method when overriding.

[rafaelss95]

IMHO, this rule should prevent this as it does right now because any parent's lifecycle should be called by Angular itself. See angular/angular#23091 and its related issues.

[mgechev]

@jscharett makes sense to me. @rafaelss95 would you want to check if the receiver of the method call isn't super?

[kevinbuhmann]

@rafaelss95: If I understand correctly, the issue you linked to is a bug where Angular does not call a lifecycle hook that is defined in a TypeScript mixin, not a base class which is what this issue is referring to.

Angular cannot and should not call a super implementation of a lifecycle hook when it is overridden in a derived class.

Consider the following:

class BaseComponent {
  ngOnInit() {
    console.log('base component init');
  }
}

@Component({...})
class MyComponent {
  ngOnInit() {
    super.ngOnInit();
    console.log('my component init');
  }
}

The super.ngOnInit(); line should be allowed by the no-lifecycle-call rule because that is ONLY way BaseComponent#ngOnInit can be called in this case.

If you don't provide an implementation of ngOnInit in MyComponent, BaseComponent#ngOnInit would be invoked when Angular invokes MyComponent#ngOnInit simply because of how extends works. But when you override a method, the outside world (i.e Angular) cannot and should not call the super implementation.

[rafaelss95]

It's a little bit strange because at some point it worked according to this issue.

However, I've to agree with you, it makes sense to explicitly call using super as we does for every parent class.

[kevinbuhmann]

If both classes are decorated, it works differently. I'm not sure of the exact behavior when the base component class is decorated, though.