I'm working on a web app project and I'm trying to use Angular, I get some problem with component communication. For example, how a parent component exchange data with child component, how to communicate between siblings components.
If you are trying to communicate from a parent component to a child component, this is pretty clearly described using @Input and EventEmitters with @Output in the angular docs.
Angular 2 component interaction
As for communication across siblings, I posted an answer in a similar question that might help with the issue of sharing data across sibling components. Currently, i think the shared service method is the most efficient.