Angular 2 application goes through a complete set of processes or has a lifecycle from launch until the end of the application. The following diagram shows all of the Angular 2 application lifecycle processes. Here is a deion of each lifecycle hook. ngOnChanges - When the value of a data bound property changes, this method is called. ngOnInit - This is called each time the directive / component is initialized after that Angular displays data-related properties first occurs. ngDoCheck - This is for detection and to act on changes that 'Angular cannot or will not detect by itself. ngAfterContentInit - This is called in response after Angular projects with external content in the component 's view. ngAfterContentChecked - This is called in response after Angular checks the content projected in the component. ngAfterViewInit - This is called in response after Angular initializes the component views and child views. ngAfterViewChecked - This is called in response after Angular checks the component views and child views. ngOnDestroy - This is the cleanup phase just before Angular destroys the directive / component. Here is an example of a lifecycle hook implementation. In the app.component.ts file, place the following code. import Component from '@ angular / core '; @Component (selector: 'my-app ', template: values ') export class AppComponent values = ''; ngOnInit () this.values = Hello In the above program, nWe call the ngOnInit lifecycle hook to specifically mention that the value of the this.values parameter should be set to Hello . Once you've saved all the code changes and refreshed the browser, you'll get the following output.