angular - Trouble implementing an Angular2 front-end service -

my goal display logged-in user’s name.

i have back-end express service uses mongoose perform mongodb queries. i’m able see work postman. service queries “users” collection in database. takes userid , returns user’s firstname.

i’m encountering problems implementing angular2 front-end service gets userid local storage, passes back-end, , retrieves user’s firstname. want use handlebars string interpolation insert username wherever want.

loggedinuser() in code below i'm focusing.

auth.service.ts

import { injectable } '@angular/core'; import { http, headers, response } '@angular/http'; import 'rxjs/rx'; import { observable } 'rxjs';  import { user } './user.model'; import { errorservice } '../errors/error.service';  @injectable() export class authservice {   constructor(private http: http, private errorservice: errorservice) {}    loggedinuser() {     const userid = localstorage.getitem('userid');     console.log('service) user id:'  + userid);     return this.http.get('htp://localhost:3000/user/current/' + userid)       .map((response: response) => {          const user = response.json().obj;          return user;       })   }; 

when try use loggedinuser in component's html file, no output when route rendered. console.log call produces nothing in browser's console; it's if method isn't being called.

signup.component.html

username:  {{ loggedinuser }} 

https://angular.io/guide/cheatsheet explains various string interpolation techniques..

are calling service in nginit of component. like

export class mycomponent implements ngoninit {   user: user   constructor (private authservice:authservice) {}   oninit{     this.authservice.subscribe((data:user) => this.user = data)   } } 

html
username: {{ user }}