angularangular2-diangular2-injection

Getting instance of service without constructor injection


I have a @Injectable service defined in Bootstrap. I want to get the instance of the service without using constructor injection. I tried using ReflectiveInjector.resolveAndCreate but that seem to create a new instance.

The reason I'm trying to do this is I have a base component derived from many components. Now I need to access a service but I don't want to add it to the constructor because I don't want to inject the service on all of the derivative components.

TLDR: I need a ServiceLocator.GetInstance<T>()

UPDATE: Updated code for RC5+: Storing injector instance for use in components


Solution

  • Yes, ReflectiveInjector.resolveAndCreate() creates a new and unconnected injector instance.

    You can inject Angulars Injector instance and get the desired instance from it using

    constructor(private injector:Injector) {
      injector.get(MyService);
    }
    

    You also can store the Injector in some global variable and than use this injector instance to acquire provided instances for example like explained in https://github.com/angular/angular/issues/4112#issuecomment-153811572