Implementing Custom dropdown in Angular 2/4 - html

Question

I have been working on a custom dropdown functionality with a horizontal divider seperating two sets of values and have general select dropdown functionalities like using up and down arrow to navigate through the values, as well as go to specific values on press of a alphabet.
Code:
<div class="btn-group d-flex dropdown" dropdown>
<div class="floatLabelContainer w-100">
<button id="button-basic" dropdownToggle type="button" float-label [addLabel]="false" [hasFloat]="true" class="mb-2" aria-controls="dropdown-basic">
{{selectedCountry}}
<span class="caret" id="country-caret"></span>
</button>
<label for="button-basic" class="label-class" id="label-class">Country</label>
</div>
<ul id="dropdown-basic" slimScroll width="100%" height="250px" size="3px" alwaysVisible="true" wheelStep="20" *dropdownMenu
class="dropdown-menu d-block" role="menu" aria-labelledby="button-basic">
<li role="menuitem">
<a class="dropdown-item" tabindex="0" (click)="selectedCountry = country.name" *ngFor="let country of restOfCountries | orderBy : 'name'">{{country.name}}</a>
</li>
<li class="divider dropdown-divider"></li>
<li role="menuitem">
<a class="dropdown-item" tabindex="0" (click)="selectedCountry = country.name" *ngFor="let country of asianCountries | orderBy : 'name'">{{country.name}}</a>
</li>
</ul>
</div>
I have been able to achieve the divider part with the above code,
but is there away to implement arrows and alphabet press functionality also.
I would prefer to have angular specific implementation or a plugin, rather than js or jQuery

Answer 1

There is the possibility of evaluating keydown and keyup events:
https://alligator.io/angular/binding-keyup-keydown-events/
According to this you should be able to achieve this functionality by implementing click listeners such as:
<div class="btn-group d-flex dropdown"
(keydown.arrowup)="select(items[i-1])"
(keydown.arrowdown)="select(items[i+1])"
dropdown>
EDIT: so I tried this and turns out this does not work on any item on default. It works on inputs, how the example shows but I could not get i ti to work on a list by now.