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Angular 17 Overriding LifeCycle methods | Overriding vs Overloading

Overriding lifecycle methods:

If a base class defines a lifecycle method, such as ngOnInit, a child class that also implements ngOnInit overrides the base class's implementation. If you want to preserve the base class's lifecycle method, explicitly call the method with super:

@Component({ ... })

export class ListboxBase {

  protected isInitialized = false;

  ngOnInit() {

    this.isInitialized = true;

  }

}

@Component({ ... })

export class CustomListbox extends ListboxBase {

  override ngOnInit() {

    super.ngOnInit();

    /* ... */

  }

}

If a base class relies on dependency injection, the child class must explicitly pass these dependencies to super.

@Component({ ... })

export class ListboxBase {

  constructor(private element: ElementRef) { }

}

@Component({ ... })

export class CustomListbox extends ListboxBase {

  constructor(element: ElementRef) {

    super(element);

  }

}

This is the YouTube video link for this: - https://youtu.be/3R4EPBqCfNw


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