JSFiddle - React, Tailwind, and code Playground

HTML

<select name="foo">
    <option value="Bar">bar</option>
    <option value="Baz">baz</option>
</select>

CSS

select,option{
    text-transform:capitalize;
}

JavaScript

$('option').each(function() {
    t = $(this).text();
    $(this).text(t.replace(/^(.)|\s(.)/g, function($1){ return $1.toUpperCase( ); }))
});