JSFiddle - React, Tailwind, and code Playground

HTML

<select>
    <option>aaaaa</option>
    <option>bbbbb</option>
    <option>ccccc</option>
</select>

<button>button</button>

JavaScript

$('button').click(function() {
    var e = document.createEvent('MouseEvents');
    e.initMouseEvent('mousedown');
    $('select')[0].dispatchEvent(e);
});