This operator is best used when you have a group of observables and only care about the final emitted value of each. One common use case for this is if you wish to issue multiple requests on page load (or some other event) and only want to take action when a response has been received […]

As soon as a promise is made, the execution takes place. However, this is not the case with observables because they are lazy. This means that nothing happens until a subscription is made. While promises handle a single event, observable is a stream that allows passing of more than one event. A callback is made […]

@HostListener is Angular’s decorator method that’s used for listening to DOM events on the host element of both component and attribute directives. @HostListener sets the listeners once the directive is initialized and removes them automatically once the directive gets destroyed.

Interceptors provide a mechanism to intercept and/or mutate outgoing requests or incoming responses. They are very similar to the concept of middleware with a framework like Express, except for the frontend. Interceptors can be really useful for features like caching and logging.

One way to deal with getting and displaying data from an API is to route a user to a component, and then in that component’s ngOnInit hook call a method in a service to get the necessary data. While getting the data, perhaps the component can show a loading indicator. There’s another way however using […]