JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ivaynberg.github.io/select2/select2-3.4.5/select2.css">
<script src="http://ivaynberg.github.io/select2/select2-3.4.5/select2.js"></script>
<!-- подключаем jquery, select2.css, select2.js
(здесь в jsfiddle они подключены как "External Resources") -->

<select id="sel">
    <option value="1" data-flag="al">Alaska</option>
    <option value="2" data-flag="ca">Califronia</option>
    <option value="3" data-flag="vt">Vermont</option>
</select>

CSS

.select2-container{width: 200px;}
img.flag { height: 10px; width: 15px; padding-right: 10px; }

JavaScript

function format(state) {
    if (!state.id) return state.text; // optgroup
    var originalOption = state.element;
    return "<img class='flag' src='http://ivaynberg.github.io/select2/images/flags/" + $(originalOption).data('flag') + ".png'>" + state.text;
}

$("#sel").select2({
    minimumResultsForSearch: -1,
    formatResult: format,
    formatSelection: format,
    escapeMarkup: function(m) { return m; }
});