问使用angularfire2和firestore创建自动完成搜索？

EN

#movies.service.ts
import { Injectable } from '@angular/core';
import { AngularFireDatabase, FirebaseListObservable } from ' 
angularfire2/database';
@Injectable()
export class MoviesService {
  constructor(private db: AngularFireDatabase) { }
  getMovies(start, end): FirebaseListObservable<any> {
    return this.db.list('/movies', {
      query: {
        orderByChild: 'Title',
        limitToFirst: 10,
        startAt: start,
        endAt: end
      }
    });
  }
}

 <h1>Movie Search</h1>
 <input type="text" (keydown)="search($event)" placeholder="search 
  movies..." class="input">
  <div *ngFor="let movie of movies">
    <h4>{{movie?.Title}}</h4>
    <p>
     {{movie?.Plot}}
   </p>
 </div>
<div *ngIf="movies?.length < 1">
  <hr>
  <p>
    No results found :(
  </p>
</div>

import { Component, OnInit } from '@angular/core';
import { MoviesService } from '../movies.service';
import { Subject } from 'rxjs/Subject'
@Component({
  selector: 'movie-search',
  templateUrl: './movie-search.component.html',
  styleUrls: ['./movie-search.component.scss']
})
export class MovieSearchComponent implements OnInit {
  movies;
  startAt = new Subject()
  endAt = new Subject()
  constructor(private moviesSvc: MoviesService) { }
  ngOnInit() {
    this.moviesSvc.getMovies(this.startAt, this.endAt)
                  .subscribe(movies => this.movies = movies)
  }
  search($event) {
      let q = $event.target.value
      this.startAt.next(q)
      this.endAt.next(q+"\uf8ff")
  }
}