Using http with ngBootstrap Typeahead for Angular 4

I'd like to use ngBootstrap for Angular 4 Typeahead for autocomplete. The example they have for remote data retrieval is using Jsonp and not http. I've been trying to find some more info to replace Jsonp with http in that example. I'm not too familiar with Observables yet so I'm trying to learn them and get better understanding about them.

I've seen this example but it looks really simple and maybe(?) leaves out a lot... for the sake of simplicity?

Can someone point in the right direction, I'm trying to find some good examples using http with ngBootstrap Typeahead.

Edit

    {
  "took": 15,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "failed": 0
  },
  "hits": {
    "total": 9,
    "max_score": 4.2456956,
    "hits": [
      {
        "_index": "query-index",
        "_type": "autocomplete",
        "_id": "AVxqBE-3t2o4jx2g0ntb",
        "_score": 4.2456956,
        "_source": {
          "suggestions": "bruce"
        }
      },
      {
        "_index": "query-index",
        "_type": "autocomplete",
        "_id": "AVxqBE-3t2o4jx2g0ntc",
        "_score": 3.064434,
        "_source": {
          "suggestions": "bruce wayne"
        }
      },
      {
        "_index": "query-index",
        "_type": "autocomplete",
        "_id": "AVxqBE-3t2o4jx2g0ntd",
        "_score": 3.064434,
        "_source": {
          "suggestions": "bruce willis"
        }
      },

Edit 2

export class AutocompleteComponent {
  model: any;
  searching = false;
  searchFailed = false;

  constructor(private autocompleteService: Elasticsearch) {}

  //formatMatches = (query: any) => query.hits.hits._source.suggestions || '';
  //formatMatches = (query: any) => query.hits.hits || '';
  formatMatches = (query: any) => <any>response.json().hits.hits || '';
  search = (text$: Observable<string>) =>
  //search = (text$: Observable<Suggestion[]>) =>
    text$
      .debounceTime(300)
      .distinctUntilChanged()
      //.switchMap(term =>
      //Observable.fromPromise(this.autocompleteService.search(term)
      .switchMap(term =>
      this.autocompleteService.search(term)
      .do( () => this.searchFailed = false)
      .catch( () => {
        this.searchFailed = true;
        return Observable.of([]);
      }))
      .do( () => this.searching = false);
}