<vaadin-combo-box> is a Web Component combining a dropdown list with an input field for filtering the list of items, part of the Vaadin components.
<vaadin-combo-box label="User" placeholder="Please select" item-value-path="email" item-label-path="email"></vaadin-combo-box>
<script>
const comboBox = document.querySelector('vaadin-combo-box');
fetch('https://randomuser.me/api?results=100&inc=name,email')
.then(res => res.json())
.then(json => comboBox.items = json.results);
</script>