Unsubscribing from Angular HttpClient data requests observables

Intro

Just recently, in one of my Angular applications, I decided to to use HttpClient data-request functions nearly directly in the components. This application is very simple: only a couple of components and services bid together to communicate with an API. That's why I decided not to build any fancy state management mechanism, but simply provide services that are acting as data-providers, and make use of those services directly in the components.

Case of unsubscribing

While subscribing on data providing observables directly in the components, I started wondering about unsubscribing of those once the component will get destroyed in the applications lifecycle.

Unsubscribing from the observables in the ngOnDestroy lifecycle phase is a good practice, not only because it helps to avoid memory leaks in your application, but also long-living subscriptions may influence your app's logic.

After a bit of thinking and googling around, it turned out that there is no need to unsubscribe for the observables that come from the HttpClient data providing methods (i.e.. .get()) as those observables are finite.

A finite observable is the one that completes.
That means that after emitting the first value of…