Question

When should you use the Angular lifecycle hook `ngOnDestroy()`?

a) To respond after Angular checks the component's views and child views
b) To initialize component data
c) To perform cleanup just before Angular destroys the directive or component
d) To subscribe to Observables

Answer 1

The Angular lifecycle hook ngOnDestroy() is used to perform cleanup just before Angular destroys the directive or component. It is commonly used for releasing resources, unsubscribing from Observables, or terminating any ongoing processes or connections.

Step-by-step explanation:

The Angular lifecycle hook ngOnDestroy() is used to perform cleanup just before Angular destroys the directive or component. It is commonly used for releasing resources, unsubscribing from Observables, or terminating any ongoing processes or connections.

For example, if a component subscribes to an Observable in the ngOnInit() hook, it should unsubscribe from that Observable in the ngOnDestroy() hook to prevent memory leaks.

In addition, the ngOnDestroy() hook is also a good place to clean up things like timers, interval subscriptions, or any other resources that are no longer needed.