Question - What are Lifecycle hooks in Angular? Explain some life cycle hooks.
Answer -
Angular components enter their lifecycle from the time it is created to the time it is destroyed. Angular hooks provide ways to tap into these phases and trigger changes at specific phases in a lifecycle.
- ngOnChanges(): This method is called whenever one or more input properties of the component changes. The hook receives a SimpleChanges object containing the previous and current values of the property.
- ngOnInit(): This hook gets called once, after the ngOnChanges hook.
- It initializes the component and sets the input properties of the component.
- ngDoCheck(): It gets called after ngOnChanges and ngOnInit and is used to detect and act on changes that cannot be detected by Angular.
- We can implement our change detection algorithm in this hook.
- ngAfterContentInit(): It gets called after the first ngDoCheck hook. This hook responds after the content gets projected inside the component.
- ngAfterContentChecked(): It gets called after ngAfterContentInit and every subsequent ngDoCheck. It responds after the projected content is checked.
- ngAfterViewInit(): It responds after a component's view, or a child component's view is initialized.
- ngAfterViewChecked(): It gets called after ngAfterViewInit, and it responds after the component's view, or the child component's view is checked.
- ngOnDestroy(): It gets called just before Angular destroys the component. This hook can be used to clean up the code and detach event handlers.