which lifecycle hook in angular do i need to use to execute whenever there is a change in the form code example

Example: angular lifecycle hooks

AngularJS lifecycle hooks
Angular gives us 8 hooks to allow us to tap into the lifecycle of our components and trigger actions at specific points in the lifecycle.

1. ngOnChanges
2. ngOnInit
3. ngDoCheck
4. ngAfterContentInit
5. ngAfterContentChecked
6. ngAfterViewInit
7. ngAfterViewChecked
8. ngOnDestroy