title: Subscribe is not a function error
body: <p>I am trying to subscribe to an observable from a service, it builds without error but I get the error "this.service.getBanners(...).subscribe is not a function" when viewing in the browser.</p>
  
  <p>Service:</p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { Observable } from 'rxjs';
  
  @Injectable()
  
  export class BannerService {
  
      banners: any = ['1','2','3'];
  
      constructor(
      ) {}
  
      getBanners(): Observable&lt;any[]&gt; {
          return this.banners;
      }
  
      setBanners(banners: any[]): void {
          this.banners = banners;
      }
  
  }
  </code></pre>
  
  <p>Component:</p>
  
  <pre><code>import { Component, ViewEncapsulation, OnInit } from '@angular/core';
  import { Observable } from 'rxjs';
  import { BannerService } from './../banner/banner.service';
  
  @Component({
      selector: '.banner',
      templateUrl: './banner.component.html',
      styleUrls: ['./banner.component.sass'],
      encapsulation: ViewEncapsulation.None
  })
  
  export class BannerComponent implements OnInit {
  
      banners: any[];
  
      constructor(private bannerService: BannerService){
  
      }
  
      ngOnInit() {
          this.bannerService.getBanners().subscribe(banners =&gt; this.banners = banners);
      }
  }
  </code></pre>
  
  <p>Any ideas what I am doing wrong?</p>