title: Disable dropdown in ng-bootstrap?
body: <p>Is there a way to disable the dropdown in ng-bootstrap? I have my own custom dropdown table that I want to use as the dropdown.</p>
  
  <p>I want something like this, that has the typeahead autofill but without the dropdown.  </p>
  
  <pre><code>&lt;p&gt;This typeahead shows a hint when the input matches because the default values have been customized.&lt;/p&gt;
  
  &lt;label for="typeahead-config"&gt;Search for a state:&lt;/label&gt;
  &lt;input id="typeahead-config" type="text" class="form-control" [(ngModel)]="model" [ngbTypeahead]="search" /&gt;
  
  
  
  import {Component} from '@angular/core';
  import {Observable} from 'rxjs/Observable';
  import {NgbTypeaheadConfig} from '@ng-bootstrap/ng-bootstrap';
  import 'rxjs/add/operator/map';
  import 'rxjs/add/operator/debounceTime';
  import 'rxjs/add/operator/distinctUntilChanged';
  
  const states = ['Alabama', 'Alaska', 'American Samoa', 'Arizona', 'Arkansas', 'California', 'Colorado',
    'Connecticut', 'Delaware', 'District Of Columbia', 'Federated States Of Micronesia', 'Florida', 'Georgia',
    'Guam', 'Hawaii', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky', 'Louisiana', 'Maine',
    'Marshall Islands', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi', 'Missouri', 'Montana',
    'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico', 'New York', 'North Carolina', 'North Dakota',
    'Northern Mariana Islands', 'Ohio', 'Oklahoma', 'Oregon', 'Palau', 'Pennsylvania', 'Puerto Rico', 'Rhode Island',
    'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont', 'Virgin Islands', 'Virginia',
    'Washington', 'West Virginia', 'Wisconsin', 'Wyoming'];
  
  @Component({
    selector: 'ngbd-typeahead-config',
    templateUrl: './typeahead-config.html',
    styles: [`.form-control { width: 300px; }`],
    providers: [NgbTypeaheadConfig] // add NgbTypeaheadConfig to the component providers
  })
  export class NgbdTypeaheadConfig {
    public model: any;
  
    constructor(config: NgbTypeaheadConfig) {
      // customize default values of typeaheads used by this component tree
      config.showHint = true;
    }
  
    search = (text$: Observable&lt;string&gt;) =&gt;
      text$
        .debounceTime(200)
        .distinctUntilChanged()
        .map(term =&gt; term.length &lt; 2 ? []
          : states.filter(v =&gt; v.toLowerCase().startsWith(term.toLocaleLowerCase())).splice(0, 10));
  }
  </code></pre>