Is it always necessary to load a service in Angular2?

Question

JavaScript

Hello, I have a question. I have a ngTranslate service that is responsible for languages ​​and I loaded it in app.component in the main application component for switching. I have created another component that lies in the main component and I want to switch the language through it, so I must "inject" this service into it. But if I add it to the main component, can I give control to the child components?

Answer 1

The service must be specified in the component's Providers or at least one of its parent components.
I have all services connected in Providers of the main component (AppComponent).
If you add a service to the providers for each component, then the instances of the services when you insert (Inject'e) into the corresponding components will differ.

Answer 2

Well, something like this, of course, put your own plus / minus icons, but the code is working, even if you just click on dummies where there should be plus / minus, the number will change
jsfiddle

Answer 3

Required. At a minimum, to handle clicks on + - and show / hide the block