MapModule.ts

export class MapModule {
    //create a static function with the mapConfig as a parameter
    static forRoot(mapConfig: IMapsConfig): ModuleWithProviders {
        return {
          ngModule: MapModule,
          //We provide a MapsConfig InjectionToken, which we later can use in our service to use
          providers: [ {provide: MapsConfig, useValue: mapConfig} ]
        };
    }
 }