ngOnChanges(): Respond when Angular (re)sets data-bound input properties. The method receives a SimpleChanges object of current and previous property values. Called before ngOnInit() and whenever one or more data-bound input properties change.
ngOnInit(): Initialize the directive/component after Angular first displays the data-bound properties and sets the directive/component's input properties. Called once, after the first ngOnChanges().
ngDoCheck(): Detect and act upon changes that Angular can't or won't detect on its own. Called during every change detection run, immediately after ngOnChanges() and ngOnInit().
ngAfterContentInit() : Respond after Angular projects external content into the component's view / the view that a directive is in. Called once after the first ngDoCheck().
ngAfterContentChecked(): Respond after Angular checks the content projected into the directive/component. Called after the ngAfterContentInit() and every subsequent ngDoCheck().
ngAfterViewInit() : Respond after Angular initializes the component's views and child views / the view that a directive is in. Called once after the first ngAfterContentChecked().
ngAfterViewChecked() : Respond after Angular checks the component's views and child views / the view that a directive is in. Called after the ngAfterViewInit() and every subsequent ngAfterContentChecked().
ngOnDestroy() : Cleanup just before Angular destroys the directive/component. Unsubscribe Observables and detach event handlers to avoid memory leaks. Called just before Angular destroys the directive/component.
