Angular Interview Practice

What happens during the destruction phase in Angular?

1. Angular invokes ngOnInit to set up new components

2. Angular cleans up resources by calling ngOnDestroy

3. Angular refreshes the entire application

4. Angular compiles all templates

The correct answer is: Angular cleans up resources by calling ngOnDestroy

During the destruction phase in Angular, the framework calls the ngOnDestroy lifecycle hook to facilitate resource cleanup before a component or directive is removed from the DOM. This is a critical phase as it provides an opportunity for the developer to perform any necessary cleanup tasks, such as unsubscribing from observable subscriptions, detaching event handlers, or clearing timers. By using ngOnDestroy, developers can prevent memory leaks and ensure that all resources utilized by a component are properly released when the component is no longer needed. This process is essential for managing the lifecycle effectively, especially in applications that create and destroy components frequently. Unlike setting up new components (which is related to ngOnInit) or refreshing the entire application, the ngOnDestroy hook is specifically tied to the cleanup of individual components and ensuring that the application remains efficient and performant.