typescript - Angular 2 injected service into another service is undefined -

i'm trying create small framework make easier me implement crud functionality.

therefore i've created basehttpservice this:

... <imports> ... @injectable() export class basehttpservice {   constructor(     private http: http   ) {     console.log('ctor');     this.apiurl$.subscribe(apiurl => this.rootapiurl = apiurl.removetrailingslash());   }   public getpagedresultoftype<t extends ibaseentity>(url: string, vm: isearchvm<t>, options?: requestoptions): observable<pagedresult<t>>{ ... <implementation> ... }   ... <other methods> ... } 

then have baseentityreadonlyservice uses basehttpservice create read fucntionality of crud:

@injectable() export class baseappsumentityreadonlyservice<t extends ibaseentity>{   constructor(     @inject(forwardref(() => basehttpservice)) public basehttpservice: basehttpservice     // public basehttpservice: basehttpservice   ) {      console.log('ro ctor');     console.log(this.basehttpservice); // <-- undefined   }    getall(vm: isearchvm<t>): observable<pagedresult<t>>{     const url = `${this.baseurl}`;     console.log(this.basehttpservice);     return this.basehttpservice.getpagedresultoftype<t>(url, vm); // <-- fails because basehttpservice undefined: cannot read property 'getpagedresultoftype' of undefined   }   ... <more methods> } 

in frameworkmodule, i've tried alot:

@ngmodule({   declarations: [     ...   ],   imports: [     commonmodule,     httpmodule   ],   providers: [     basehttpservice,     // baseappsumentityreadonlyservice     { provide: baseappsumentityreadonlyservice, useclass: baseappsumentityreadonlyservice, deps: [ basehttpservice ] },   ] }) export class appsumframeworkmodule { } 

this have, not work. error is:

cannot read property 'getpagedresultoftype' of undefined

how can basehttpservice injected in baseappsumentityreadonlyservice?

import service this:

import { basehttpservice} '../servicepath'; 

then declare in constructor:

constructor(     private basehttpservice: basehttpservice   ) {      console.log(this.basehttpservice);    } 

let me know if works this, , if not, copy/paste console error please. :d

edit 1:

service: basehttpservice

... <imports> ... @injectable() export class basehttpservice {   constructor(     private http: http   ) {     console.log('ctor');     this.apiurl$.subscribe(apiurl => this.rootapiurl = apiurl.removetrailingslash());   }   public getpagedresultoftype<t extends ibaseentity>(url: string, vm: isearchvm<t>, options?: requestoptions): observable<pagedresult<t>>{ ... <implementation> ... }   ... <other methods> ... } 

service: baseappsumentityreadonlyservice

@injectable() export class baseappsumentityreadonlyservice<t extends ibaseentity>{   constructor(     private basehttpservice: basehttpservice   ) {      console.log('ro ctor');     console.log(this.basehttpservice); // <-- undefined   }    getall(vm: isearchvm<t>): observable<pagedresult<t>>{     const url = `${this.baseurl}`;     console.log(this.basehttpservice);     return this.basehttpservice.getpagedresultoftype<t>(url, vm); // <-- fails because basehttpservice undefined: cannot read property 'getpagedresultoftype' of undefined   }   ... <more methods> } 

module:

@ngmodule({   declarations: [     mycomponent   ],   imports: [     commonmodule,     httpmodule   ],   providers: [     basehttpservice,     baseappsumentityreadonlyservice,   ] }) export class appsumframeworkmodule { } 

component: mycomponent

... <imports> ... @component() export class mycomponent {  constructor(     private baseappservice: baseappsumentityreadonlyservice   ) {      console.log(this.baseappservice);    } }