Angular 5 Dependency Injection - is there another way besides using constructor()?

Question

I have a service declared in my module.ts file to have an application-wide scope. The way to access the instance of this service is to declare it as part of the constructor for the component class, like so, and the framework automatically wires it up:

export class ComponentBase implements OnInit {

  constructor(private myService: MyService) { }
}

My component class is one of several similar components, so they all share a common base class, and this constructor is on the base. I discovered that base constructors are not automatically required, so it is possible that a derived class ends up without a constructor (and without the dependency).

So, is there another, more foolproof way to do it in the base class?

Answer 1

The injections are provided as a constructor parameters: - you can set the class directly, like this:

constructor(private myService: MyService)

• or using the injector:

  constructor(injector: Injector){ this.myService = injector.get(MyService); }