Angular2 calling a service from another service

I have 2 services - 1/Files and 2/FTPClient in angular2.

They are Singleton services - and work perfectly when injected into a component through its constructor like this :

constructor(public filesIn:Files, public ftpIn:FTPClient){}

SO now I would like to use the Files server within the FTPClient itself...so I try the same thing. This is my code for the constructor of the FTPClient service:

constructor(public filesIn:Files) {
        this.files = filesIn;
    }

But this throws the error:

Can't resolve all parameters for FTPClient (?)

My application only has one module - and both the Files and FTPClient are in the providers list :

 providers: [APIData,FTPClient,Files,SSHClient, WINDOW_PROVIDER]

Please can you shed some light on what I am doing wrong here!


ANSWERS:


I had to add the @Injectable() decorator just above my class began - and import Injectable into the file by including the line :

import { Injectable } from '@angular/core';


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