angular 2 autocomplete service using rxjs

optimized_autocomplete_service.ts

import {Injectable} from '@angular/core';
import { URLSearchParams, Jsonp } from '@angular/http';
import { Observable } from 'rxjs/Observable';

@Injectable()
export class WikipediaSearchService {

  constructor(private jsonp: Jsonp, private url: string) { }
  search(terms: Observable<string>, debounceMs = 400) {
    return terms.debounceTime(400)
      .distinctUntilChanged()
      .switchMap(term => this.rawSearch(term));
  }

  rawSearch(term: string) {
    let search = new URLSearchParams();
    search.set('action', 'opensearch');
    search.set('search', term);
    search.set('format', 'json');
    return this.jsonp.get(this.url)
      .map(response => response.json()[1]);
  }
}

Pulled directly from https://egghead.io/lessons/angular-2-building-an-instant-search-with-angular-2-building-fully-reactive-apis?series=build-an-angular-2-instant-search-component#/tab-discuss