why ActivatedRoute in @angular\router params is observable?

Question

why ActivatedRoute in @angular\\router params is observable ?

I\'m wondering why do I need to subscribe for Params ? and why params are async

Answer 1

The matrix parameters scoped to this route. The observable will emit a new value when the set of the parameters changes.

The reason that the params property on ActivatedRoute is an Observable is that the router may not recreate the component when navigating to the same component. In this case the parameter may change without the component being recreated.

Answer 2

You can use

route.routerState.params

You can subscribe because when your application navigates to the same route with just another parameter value, the component is not recreated and you have no way of knowing when the parameters have changes.

With subscribing to parameters you get notified, that a route action has happened where only the parameter value changed.