title: Angular 4: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe'
body: <p>i need your help, i'm trying to display some datas from my firebase but it trhows me an error like <code>InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe'</code>.</p>
  
  <hr>
  
  <p>There is my service: </p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { AngularFireDatabase } from 'angularfire2/database';
  
  @Injectable()
  export class MoviesService {
  
    constructor(private db: AngularFireDatabase) {}
    get = () =&gt; this.db.list('/movies');
  }
  </code></pre>
  
  <hr>
  
  <p>There is my component:</p>
  
  <pre><code>import { Component, OnInit } from '@angular/core';
  import { MoviesService } from './movies.service';
  
  @Component({
    selector: 'app-movies',
    templateUrl: './movies.component.html',
    styleUrls: ['./movies.component.css']
  })
  export class MoviesComponent implements OnInit {
    movies: any[];
  
    constructor(private moviesDb: MoviesService) { }
  
    ngOnInit() {
      this.moviesDb.get().subscribe((snaps) =&gt; {
        snaps.forEach((snap) =&gt; {
          this.movies = snap;
          console.log(this.movies);
        });
     });
   }
  }
  </code></pre>
  
  <hr>
  
  <p>And there is mmy pug:</p>
  
  <pre><code>ul
    li(*ngFor='let movie of (movies | async)')
      | {{ movie.title | async }}
  </code></pre>