Service Dependencies in NestJS - dependency-injection

Question

I have many endpoints in my app:
/Route1
/Route2
...
/Route99
In a number of these routes, there is some common functionality such as getting specific data from one source such as a local file, or another resource such as a No SQL database or external HTTP endpoint. My problem is that these services need to have a service dependency themselves, and I am not sure that how I have currently done it is the best way to do it in NestJS.
Route1Service - Read a file of data, and return it. This uses the FileSystemService() to wrap all the error handling, different data types, path checking etc., of the NodeJS fs module. The Route1Service then returns this to the Route1Controller
#Injectable()
export class Route1Service {
private FS_:FileSystemService; // defined here instead of constructor, as I do not know how to set it in the constructor via NestJS, or if this is even the best way.
// constructor(private FS_: FileSystemService) { }
// Since I do not set it in the constructor
public DataServiceDI(FsService:FileSystemService):void {
this.FS_ = FsService;
}
public GetData(): string {
const Data:string = this.FS_.ReadLocalFile('a.txt');
return Data;
}
}
Route99Service might do the same thing, but with a different file (b.txt)
#Injectable()
export class Route99Service {
private FS_:FileSystemService;
public DataServiceDI(FsService:FileSystemService):void {
this.FS_ = FsService;
}
public GetData(): string {
const Data:string = this.FS_.ReadLocalFile('b.txt');
return Data;
}
}
This is a contrived example to illustrate my issue. Obviously a basic RouteService could be used, and pass the file name, but I am trying to illustrate the dependent service. I do not know how to define the module(s) to use this dependent service or if I should be doing it this way.
What I have been doing for my definition:
#Module({
controllers: [Route1Controller],
providers: [Route1Service, FileSystemService],
})
export class Route1Module {}
The controller than has the constructor with both Services:
#Controller('route1')
export class Route1Controller
constructor(
private Route1_: Route1Service,
private FsSystem_: FileSystemService
) { }
Now that my controller has the FsSystem service as a separate entity, I need to add a method on my Route1Service, DataServiceDI(), to allow me to pass the FileSystemService as a reference. Then my service can use this service to access the file system.
My question comes down to, is this the best practice for this sort of thing? Ultimately, in my code, these services (FileSystemService, NoSqlService) extend a common service type, so that all my services can have this DataServiceDI() in then (they extend a base service with this definition).
Is this the best approach for longer term maintainability? Is there an easier way to simply inject the proper service into my Route1Service so it is injected by NestJS, and I do not have to do the DI each time?
The current method works for me to be able to simply test the service, since I can easily mock the FileSystemServie, NoSqlService, etc., and then inject the mock.